the purpose of dreams essay

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Why Your Brain Needs to Dream

We often hear stories of people who’ve learned from their dreams or been inspired by them. Think of Paul McCartney’s story of how his hit song “Yesterday” came to him in a dream or of Mendeleev’s dream-inspired construction of the periodic table of elements.

But, while many of us may feel that our dreams have special meaning or a useful purpose, science has been more skeptical of that claim. Instead of being harbingers of creativity or some kind of message from our unconscious, some scientists have considered dreaming to be an unintended consequence of sleep—a byproduct of evolution without benefit.

Sleep itself is a different story. Scientists have known for a while now that shorter sleep is tied to dangerous diseases, like heart disease and stroke . There is mounting evidence that sleep deprivation leads to a higher risk of obesity and Alzheimer’s disease . Large population studies reflect a saddening truth—the shorter your sleep, the shorter your life . Not only that, sleep helps us to hold onto our memories and to learn facts and skills faster, making it important for everyone including infants, students, athletes, pilots, and doctors.

Much of this I outline in my new book, Why We Sleep: Unlocking the Power of Sleep and Dreams , which summarizes the many findings we have about sleep and its function in our lives.

But what about dreaming? Does it also have a purpose?

Recent work in my neuroscience lab and the work of other scientists has shown that dreams may have a very particular function important to our well-being. Here are the two main ways dreams help us.

Dreaming is like overnight therapy

It’s said that time heals all wounds, but my research suggests that time spent in dream sleep is what heals. REM-sleep dreaming appears to take the painful sting out of difficult, even traumatic, emotional episodes experienced during the day, offering emotional resolution when you awake the next morning.

REM sleep is the only time when our brain is completely devoid of the anxiety-triggering molecule noradrenaline. At the same time, key emotional and memory-related structures of the brain are reactivated during REM sleep as we dream. This means that emotional memory reactivation is occurring in a brain free of a key stress chemical, which allows us to re-process upsetting memories in a safer, calmer environment.

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How do we know this is so? In one study in my sleep center, healthy young adult participants were divided into two groups to watch a set of emotion-inducing images while inside an MRI scanner. Twelve hours later, they were shown the same emotional images—but for half the participants, the twelve hours were in the same day, while for the other half the twelve hours were separated by an evening of sleep.

Those who slept in between the two sessions reported a significant decrease in how emotional they felt in response to seeing those images again, and their MRI scans showed a significant reduction in reactivity in the amygdala, the emotional center of the brain that creates painful feelings. Moreover, there was a reengagement of the rational prefrontal cortex of the brain after sleep that helped maintain a dampening influence on emotional reactivity. In contrast, those who remained awake across the day showed no such dissolving of emotional reactivity over time.

That in itself doesn’t say anything about the role of dreaming. But we had recorded each participant’s sleep during the intervening night between the two test sessions, and we found that specific brain activity that reflected a drop in stress-related brain chemistry during the dream state determined the success of overnight therapy from one individual to the next.

Dreaming has the potential to help people de-escalate emotional reactivity, probably because the emotional content of dreams is paired with a decrease in brain noradrenaline. Support for this idea came from a study done by Murray Raskind on vets with PTSD, who often suffer debilitating nightmares. When given the drug Prazosin—a medication that lowers blood pressure and also acts as a blocker of the brain stress chemical noradrenaline—the vets in his study had fewer nightmares and fewer PTSD symptoms than those given a placebo. Newer studies suggest this effect can be shown in children and adolescents with nightmares, as well, though the research on this is still in its infancy.

The evidence points toward an important function of dreams: to help us take the sting out of our painful emotional experiences during the hours we are asleep, so that we can learn from them and carry on with our lives.

Dreaming enhances creativity and problem-solving

It’s been shown that deep non-REM sleep strengthens individual memories. But REM sleep is when those memories can be fused and blended together in abstract and highly novel ways. During the dreaming state, your brain will cogitate vast swaths of acquired knowledge and then extract overarching rules and commonalties, creating a mindset that can help us divine solutions to previously impenetrable problems.

How do we know dreaming and not just sleep is important to this process?

In one study , we tested this by waking up participants during the night—during both non-REM sleep and dreaming sleep—and gave them very short tests: solving anagram puzzles, where you try to unscramble letters to form a word (e.g., OSEOG = GOOSE). First, participants were tested beforehand, just to familiarize them with the test. Then, we monitored their sleep and woke them up at different points of the night to perform the test. When woken during non-REM sleep, they were not particularly creative—they could solve very few puzzles. But, when we woke up participants during REM sleep, they were able to solve 15-35 percent more puzzles than when they were awake. Not only that, participants woken while dreaming reported that the solution just “popped” into their heads, as if it were effortless.

In another study , I and my colleagues taught participants a series of relational facts—such as, A>B, B>C, C>D, and so on—and tested their understanding by asking them questions (e.g., Is B>D or not? ). Afterwards, we compared their performance on this test before and after a full night’s sleep, and also after they’d had a 60- to 90-minute nap that included REM sleep. Those who’d slept or had a long nap performed much better on this test than when they were awake, as if they’d put together disparate pieces of a jigsaw puzzle in their sleep.

Some may consider this trivial, but it is one of the key operations differentiating your brain from your computer. It also underlies the difference between knowledge (retention of individual facts) and wisdom (knowing what they all mean when you fit them together). The latter seems to be the work of REM-sleep dreaming.

“It’s said that time heals all wounds, but my research suggests that time spent in dream sleep is what heals”

Dreaming improves creative problem solving, too, according to another study . Participants learned to navigate a virtual maze using trial and error and aided by the placement of unique objects—like Christmas trees—at certain junctions in the maze. After this learning session, the group was split in two, with half napping and half watching a video for 90 minutes. Nappers were occasionally awoken to ask about the content of their dreams; those watching a video were also asked about thoughts going through their minds.

Afterwards, the participants again tried to solve the maze, and those who napped were significantly better at it than those who didn’t, as expected. But the nappers who reported dreaming about the maze were 10 times better at the task than those who napped and didn’t dream about the maze. There’s a reason you’ve never been told to stay awake on a problem.

Looking at the content of these dreams, it was clear that the participants didn’t dream a precise replay of the learning experience while awake. Instead, they were cherry-picking salient fragments of the learning experience and attempting to place them within the catalog of preexisting knowledge. This is how dreaming helps us be more creative.

While the benefits of dreaming are real, too many of us have problems getting a full eight hours of sleep and lose out on these advantages. Alternatively, we may think we’re the exception to the rule—that we’re one of those people who doesn’t happen to need a lot of sleep. But nothing could be further from the truth. Research clearly shows that people who overestimate their ability to get by on less sleep are sadly wrong.

Five ways to enhance your sleep

So how can we be sure to get enough sleep and experience a dream state? While we may be tempted to use sleeping pills to get to sleep, this has been shown to be detrimental to dreaming. Instead of taking pills, here are some simple ways to enhance your sleep:

1. Make sure your room is dark and that you are not looking at bright light sources—i.e., computer screens and cell phones—in the last hour or two before going to bed. You may even want to start dimming lights in your house in the earlier parts of the evening, which helps to stimulate sleepiness.

2. Go to bed and wake up at approximately the same time every day. This helps signal to your body a regular time for sleeping. It’s no use trying to sleep in a lot on weekends. There is no way to make up for regular sleep loss during the week.

3. Keep the temperature in your house cool at night—maybe even cooler than you think it should be, like around 65 degrees. Your body temperature needs to drop at night for sleep, and a lower room temperature helps signal your brain that it’s time to sleep.

4. If you have trouble falling asleep, or wake in the night feeling restless, don’t stay in bed awake. That trains the brain that your bed is not a place for sleeping. Instead, get up and read a book under dim light in a different room. Don’t look at your computer or cell phone. When sleepiness returns, then go back to bed. Or if you don’t want to get out of bed, try meditating. Studies suggest it helps individuals fall asleep faster, and also improves sleep quality.

5. Don’t have caffeine late in the day or an alcohol-infused nightcap. Both of these interfere with sleep—either keeping you awake or stimulating frequent wake-ups during the night.

Sleep is the single most effective thing we can do to rest our brain and physical health each day. Atop of sleep, dreaming provides essential emotional first aid and a unique form of informational alchemy. If we wish to be as healthy, happy, and creative as possible, these are facts well worth waking up to.

About the Author

Matthew Walker

Matthew Walker is a professor of psychology and neuroscience at the University of California, Berkeley, and the director of the university’s Center for Human Sleep Science .

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Essays About Dreams In Life: 14 Examples And Topic Ideas

Dreams in life are necessary; if you are writing essays about dreams in life, you can read these essay examples and topic ideas to get started.

Everyone has a dream – a big one or even a small one. Even the most successful people had dreams before becoming who they are today. Having a dream is like having a purpose in life; you will start working hard to reach your dream and never lose interest in life.

Without hard work, you can never turn a dream into a reality; it will only remain a desire. Level up your essay writing skills by reading our essays about dreams in life examples and prompts and start writing an inspiring essay today!

Writing About Dreams: A Guide

Essays about dreams in life: example essays, 1. chase your dreams: the best advice i ever got by michelle colon-johnson, 2. my dream, my future by deborah massey, 3. the pursuit of dreams by christine nishiyama, 4. my dreams and ambitions by kathy benson, 5. turning big dreams into reality by shyam gokarn, 6. my hopes and dreams by celia robinson, 7. always pursue your dreams – no matter what happens by steve bloom, 8. why do we dream by james roland, 9. bad dreams by eli goldstone, 10. why your brain needs to dream by matthew walker, 11. dreams by hedy marks, 12. do dreams really mean anything by david b. feldman, 13. how to control your dreams by serena alagappan, 14. the sunday essay: my dreams on antidepressants by ashleigh young, essays about dreams in life essay topics, 1. what is a dream, 2. what are your dreams in life, 3. why are dreams important in life, 4. what are the reasons for a person to dream big, 5. what do you think about dreams in life vs. short-term sacrifice, 6. what is the purpose of dreaming, 7. why are dreams so strange and vivid, 8. why do dreams feel so real, 9. why are dreams so hard to remember, 10. do dreams mean anything, what is a dream short essay, how can i write my dream in life.

Writing about dreams is an excellent topic for essays, brainstorming new topic ideas for fiction stories, or just as a creative outlet. We all have dreams, whether in our sleep, during the day, or even while walking on a sunny day. Some of the best ways to begin writing about a topic are by reading examples and using a helpful prompt to get started. Check out our guide to writing about dreams and begin mastering the art of writing today!

“Everyone has the ability to dream, but not everyone has the willingness to truly chase their dreams. When people aren’t living their dreams they often have limited belief systems. They believe that their current circumstances and/or surroundings are keeping them from achieving the things they want to do in life.”

In her essay, author Michelle Colon-Johnson encourages her readers to develop a mindset that will let them chase their dreams. So, you have to visualize your dream, manifest it, and start your journey towards it! Check out these essays about dreams and sleep .

“At the time when I have my job and something to make them feel so proud of me, I would like to give them the best life. I would like to make them feel comfortable and see sweet smiles on their faces. This is really the one I like to achieve in my life; mountains of words can’t explain how much I love and appreciate them.”

Author Deborah Massey’s essay talks about her dreams and everything she wanted to achieve and accomplish in her life. She also tells us that we must live our values, pursue our dreams, and follow our passions for the best future.

“Fast-forward 5+ years, and my first published book is coming out this May with Scholastic. And now, let me tell you the truth: I don’t feel any different. I’m extremely grateful for the opportunity, proud of the work I’ve done, and excited for the book’s release. But on a fundamental level, I feel the same.”

In her essay, author Christine Nishiyama shares what she felt when she first achieved one of her goals in life. She says that with this mindset, you will never feel the satisfaction of achieving your goal or the fulfillment of reaching your dream. Instead, she believes that what fulfills people is the pursuit of their dreams in life.

“My dream is to become a good plastic surgeon and day after day it has transformed into an ambition which I want to move towards. I do not want to be famous, but just good enough to have my own clinic and work for a very successful hospital. Many people think that becoming a doctor is difficult, and I know that takes many years of preparation, but anyone can achieve it if they have determination.”

Author Kathy Benson’s essay narrates her life – all the things and struggles she has been through in pursuing her dreams in life. Yet, no matter how hard the situation gets, she always convinces herself not to give up, hoping her dreams will come true one day. She believes that with determination and commitment, anyone can achieve their dreams and goals in life. 

“I have always been a big dreamer and involved in acting upon it. Though, many times I failed, I continued to dream big and act. As long as I recollect, I always had such wild visions and fantasies of thinking, planning, and acting to achieve great things in life. But, as anyone can observe, there are many people, who think and work in that aspect.”

In his essay, author Shyam Gokarn explains why having a big dream is very important in a person’s life. However, he believes that the problem with some people is that they never hold tight to their dreams, even if they can turn them into reality. As a result, they tend to easily give up on their dreams and even stop trying instead of persevering through the pain and anguish of another failure.

“When I was younger, I’ve always had a fairytale-like dream about my future. To marry my prince, have a Fairy Godmother, be a princess… But now, all of that has changed. I’ve realized how hard life is now; that life cannot be like a fairy tale. What you want can’t happen just like that.”

Celia Robinson’s essay talks about her dream since she was a child. Unfortunately, as we grow old, there’s no “Fairy Godmother” that would help us when things get tough. Everyone wants to succeed in the future, but we have to work hard to achieve our dreams and goals.

“Take writing for example. I’ve wanted to be a professional writer since I was a little boy, but I was too scared that I wouldn’t be any good at it. But several years ago I started pursuing this dream despite knowing how difficult it might be. I fully realize I may not make it, but I’m completely fine with that. At least I tried which is more than most people can say.”

In his essay, author Steve Bloom encourages his readers always to pursue their dreams no matter what happens. He asks, “Would you rather pursue them and fail or never try?”. He believes that it’s always better to try and fail than look back and wonder what might have been. Stop thinking that failure or success is the only end goal for pursuing your dreams. Instead, think of it as a long journey where all the experiences you get along the way are just as important as reaching the end goal.

“Dreams are hallucinations that occur during certain stages of sleep. They’re strongest during REM sleep, or the rapid eye movement stage, when you may be less likely to recall your dream. Much is known about the role of sleep in regulating our metabolism, blood pressure, brain function, and other aspects of health. But it’s been harder for researchers to explain the role of dreams. When you’re awake, your thoughts have a certain logic to them. When you sleep, your brain is still active, but your thoughts or dreams often make little or no sense.”

Author James Roland’s essay explains the purpose of having dreams and the factors that can influence our dreams. He also mentioned some of the reasons that cause nightmares. Debra Sullivan, a nurse educator, medically reviews his essay. Sullivan’s expertise includes cardiology, psoriasis/dermatology, pediatrics, and alternative medicine. For more, you can also see these articles about sleep .

“The first time I experienced sleep paralysis and recognised it for what it was I was a student. I had been taking MDMA and listening to Django Reinhardt. My memories of that time are mainly of taking drugs and listening to Django Reinhardt. When I woke up I was in my paralysed body. I was there, inside it. I was inside my leaden wrists, my ribcage, the thick dead roots of my hair, the bandages of skin. This time the hallucinations were auditory. I could hear someone being beaten outside my door. They were screaming for help. And I could do nothing but lie there, locked inside my body . . . whatever bit of me is not my body. That is the bit that exists, by itself, at night.”

In her essay, Author Eli Goldstone talks about her suffering from bad dreams ever since childhood. She also talks about what she feels every time she has sleep paralysis – a feeling of being conscious but unable to move.

“We often hear stories of people who’ve learned from their dreams or been inspired by them. Think of Paul McCartney’s story of how his hit song “Yesterday” came to him in a dream or of Mendeleev’s dream-inspired construction of the periodic table of elements. But, while many of us may feel that our dreams have special meaning or a useful purpose, science has been more skeptical of that claim. Instead of being harbingers of creativity or some kind of message from our unconscious, some scientists have considered dreaming to being an unintended consequence of sleep—a byproduct of evolution without benefit.”

Author Matthew Walker, a professor of psychology and neuroscience, shares some interesting facts about dreams in his essay. According to research, dreaming is more than just a byproduct of sleep; it also serves essential functions in our well-being. 

“Dreams are basically stories and images that our mind creates while we sleep. They can be vivid. They can make you feel happy, sad, or scared. And they may seem confusing or perfectly rational. Dreams can happen at any time during sleep. But you have your most vivid dreams during a phase called REM (rapid eye movement) sleep, when your brain is most active. Some experts say we dream at least four to six times a night.”

In his essay, Author Hedy Marks discusses everything we need to know about dreams in detail – from defining a dream to tips that may help us remember our dreams. Hedy Marks is an Assistant Managing Editor at WebMD , and Carol DerSarkissian, a board-certified emergency physician, medically reviews his essay.

“Regardless of whether dreams foretell the future, allow us to commune with the divine, or simply provide a better understanding of ourselves, the process of analyzing them has always been highly symbolic. To understand the meaning of dreams, we must interpret them as if they were written in a secret code. A quick search of an online dream dictionary will tell you that haunted houses symbolize “unfinished emotional business,” dimly lit lamps mean you’re “feeling overwhelmed by emotional issues,” a feast indicates “a lack of balance in your life,” and garages symbolize a feeling of “lacking direction or guidance in achieving your goals.” 

Author David B. Feldman, an author, speaker, and professor of counseling psychology, believes that dreams may not mean anything, but they tell us something about our emotions. In other words, if you’ve been suffering from a series of bad dreams, it could be worth checking in with yourself to see how you’ve been feeling and perhaps consider whether there’s anything you can do to improve your mood.

“Ever wish you could ice skate across a winter sky, catching crumbs of gingerbread, like flakes of snow, on your tongue? How about conquering a monster in a nightmare, bouncing between mountain peaks, walking through walls, or reading minds? Have you ever longed to hold the hand of someone you loved and lost? If you want to fulfill your fantasies, or even face your fears, you might want to try taking some control of your dreams (try being the operative). People practiced in lucid dreaming—the phenomenon of being aware that you are dreaming while you are asleep—claim that the experience allows adventure, self-discovery, and euphoric joy.”

In her essay, Author Serena Alagappan talks about lucid dreams – a type of dream where a person becomes conscious during a dream. She also talked about ways to control our dreams, such as keeping a journal, reciting mantras before bed, and believing we can. However, not everyone will be able to control their dreams because the levels of lucidity and control differ significantly between individuals.

“There was a period of six months when I tried to go off my medication – a slowly unfolding disaster – and I’d thought my dreams might settle down. Instead, they grew more deranged. Even now I think of the dream in which I was using a cigarette lighter to melt my own father, who had assumed the form of a large candle. I’ve since learned that, apart from more research being needed, this was probably a case of “REM rebound”. When you stop taking the medication, you’ll likely get a lot more REM sleep than you were getting before. In simple terms, your brain goes on a dreaming frenzy, amping up the detail.”

Author Ashleigh Young’s essay informs us how some medications, such as antidepressants, affect our dreams based on her own life experience. She said, “I’ve tried not to dwell too much on my dreams. Yes, they are vivid and sometimes truly gruesome, full of chaotic, unfathomable violence, but weird nights seemed a reasonable price to pay for the bearable days that SSRIs have helped me to have.” 

In simple terms, a dream is a cherished aspiration, ambition, or ideal; is it the same as your goal in life? In your essay, explore this topic and state your opinion about what the word “dream” means to you.

This is an excellent topic for your statement or “about me” essay. Where do you see yourself in the next ten years? Do you have a career plan? If you still haven’t thought about it, maybe it’s time to start thinking about your future.

Having dreams is very important in a person’s life; it motivates, inspires, and helps you achieve any goal that you have in mind. Without dreams, we would feel lost – having no purpose in life. Therefore, in your essay, you should be able to explain to your readers how important it is to have a dream or ambition in life. 

Dreaming big sounds great; however, it’s easier said than done. First, you’ve got to have reasons to dream big, which will motivate you to achieve your goals in life. If you’re writing an essay about dreams in life, mention why most people dare to dream big and achieve more in life. Is it about freedom, money, praise from other people, satisfaction, or something else entirely?

For example, you could watch movies, play video games, relax every night, or give up all of them to learn a complex skill – what would you choose, and why? In your essay about dreams in life, answer the question and include other examples about this topic so your readers can relate.

There are many answers to this question – one is that dreams may have an evolutionary function, testing us in scenarios crucial to our survival. Dreams may also reduce the severity of emotional trauma. On the other hand, some researchers say dreams have no purpose or meaning, while some say we need dreams for physical and mental health. Take a closer look at this topic, and include what you find in your essay.

Weird dreams could result from anxiety, stress, or sleep deprivation. So, manage your stress levels, and stick to a sleep routine to stop having weird dreams. If you wake up from a weird dream, you can fall back asleep using deep breaths or any relaxing activity. You can research other causes of weird dreams and ways to stop yourself from having them for your essay about dreams and sleep.

The same areas of the brain that are active when we learn and process information in the actual world are active when we dream, and they replay the information as we sleep. Many things we see, hear, and feel in our everyday lives appear in our dreams. If you want to write an informative essay about dreams and sleep, look into more details about this topic.

Tip: When editing for grammar, we also recommend taking the time to improve the readability score of a piece of writing before publishing or submitting it.

People may not remember what happened in their dreams. Studies show that people tend to forget their dreams due to the changing levels of acetylcholine and norepinephrine during sleep. This will be quite an exciting topic for your readers because many people can relate. That being said, research more information about this topic, and discuss it in detail in your essay. 

Although some people believe that dreams don’t mean anything, many psychologists and other experts have theorized about the deeper meaning of dreams. Therefore, your essay about dreams and sleep should delve deeper into this topic. If you’re stuck picking your next essay topic, check out our round-up of essay topics about education .

FAQS on Essays About Dreams in Life

There are many great short essays about dreams; you can write your own too! Some great examples include Do Dreams Really Mean Anything? by David B. Feldman and  Dreams by Hedy Marks.

Writing about your dreams in life is a fantastic creative outlet and can even help you plan your future. Use a prompt to get started, like “What are your dreams in life?” or “What do you aspire to be in ten years?” and begin writing without thinking too much about it. See where the pen takes you and start mapping out your future with this writing exercise.

Meet Rachael, the editor at Become a Writer Today. With years of experience in the field, she is passionate about language and dedicated to producing high-quality content that engages and informs readers. When she's not editing or writing, you can find her exploring the great outdoors, finding inspiration for her next project.

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July 26, 2011

The Science Behind Dreaming

New research sheds light on how and why we remember dreams--and what purpose they are likely to serve

By Sander van der Linden

Getty Images

For centuries people have pondered the meaning of dreams. Early civilizations thought of dreams as a medium between our earthly world and that of the gods. In fact, the Greeks and Romans were convinced that dreams had certain prophetic powers. While there has always been a great interest in the interpretation of human dreams, it wasn’t until the end of the nineteenth century that Sigmund Freud and Carl Jung put forth some of the most widely-known modern theories of dreaming. Freud’s theory centred around the notion of repressed longing -- the idea that dreaming allows us to sort through unresolved, repressed wishes. Carl Jung (who studied under Freud) also believed that dreams had psychological importance, but proposed different theories about their meaning.

Since then, technological advancements have allowed for the development of other theories. One prominent neurobiological theory of dreaming is the “activation-synthesis hypothesis,” which states that dreams don’t actually mean anything: they are merely electrical brain impulses that pull random thoughts and imagery from our memories. Humans, the theory goes, construct dream stories after they wake up, in a natural attempt to make sense of it all. Yet, given the vast documentation of realistic aspects to human dreaming as well as indirect experimental evidence that other mammals such as cats also dream, evolutionary psychologists have theorized that dreaming really does serve a purpose. In particular, the “threat simulation theory” suggests that dreaming should be seen as an ancient biological defence mechanism that provided an evolutionary advantage because of  its capacity to repeatedly simulate potential threatening events – enhancing the neuro-cognitive mechanisms required for efficient threat perception and avoidance.

So, over the years, numerous theories have been put forth in an attempt to illuminate the mystery behind human dreams, but, until recently, strong tangible evidence has remained largely elusive.

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Yet, new research published in the Journal of Neuroscience provides compelling insights into the mechanisms that underlie dreaming and the strong relationship our dreams have with our memories. Cristina Marzano and her colleagues at the University of Rome have succeeded, for the first time, in explaining how humans remember their dreams. The scientists predicted the likelihood of successful dream recall based on a signature pattern of brain waves. In order to do this, the Italian research team invited 65 students to spend two consecutive nights in their research laboratory.

During the first night, the students were left to sleep, allowing them to get used to the sound-proofed and temperature-controlled rooms. During the second night the researchers measured the student’s brain waves while they slept. Our brain experiences four types of electrical brain waves: “delta,” “theta,” “alpha,” and “beta.” Each represents a different speed of oscillating electrical voltages and together they form the electroencephalography (EEG). The Italian research team used this technology to measure the participant’s brain waves during various sleep-stages. (There are five stages of sleep; most dreaming and our most intense dreams occur during the REM stage.) The students were woken at various times and asked to fill out a diary detailing whether or not they dreamt, how often they dreamt and whether they could remember the content of their dreams.

While previous studies have already indicated that people are more likely to remember their dreams when woken directly after REM sleep, the current study explains why. Those participants who exhibited more low frequency theta waves in the frontal lobes were also more likely to remember their dreams.

This finding is interesting because the increased frontal theta activity the researchers observed looks just like the successful encoding and retrieval of autobiographical memories seen while we are awake. That is, it is the same electrical oscillations in the frontal cortex that make the recollection of episodic memories (e.g., things that happened to you) possible. Thus, these findings suggest that the neurophysiological mechanisms that we employ while dreaming (and recalling dreams) are the same as when we construct and retrieve memories while we are awake.

In another recent study conducted by the same research team, the authors used the latest MRI techniques to investigate the relation between dreaming and the role of deep-brain structures. In their study, the researchers found that vivid, bizarre and emotionally intense dreams (the dreams that people usually remember) are linked to parts of the amygdala and hippocampus. While the amygdala plays a primary role in the processing and memory of emotional reactions, the hippocampus has been implicated in important memory functions, such as the consolidation of information from short-term to long-term memory.

The proposed link between our dreams and emotions is also highlighted in another recent study published by Matthew Walker and colleagues at the Sleep and Neuroimaging Lab at UC Berkeley, who found that a reduction in REM sleep (or less “dreaming”) influences our ability to understand complex emotions in daily life – an essential feature of human social functioning.  Scientists have also recently identified where dreaming is likely to occur in the brain.  A very rare clinical condition known as “Charcot-Wilbrand Syndrome” has been known to cause (among other neurological symptoms) loss of the ability to dream.  However, it was not until a few years ago that a patient reported to have lost her ability to dream while having virtually no other permanent neurological symptoms. The patient suffered a lesion in a part of the brain known as the right inferior lingual gyrus (located in the visual cortex). Thus, we know that dreams are generated in, or transmitted through this particular area of the brain, which is associated with visual processing, emotion and visual memories.

Taken together, these recent findings tell an important story about the underlying mechanism and possible purpose of dreaming.

Dreams seem to help us process emotions by encoding and constructing memories of them. What we see and experience in our dreams might not necessarily be real, but the emotions attached to these experiences certainly are. Our dream stories essentially try to strip the emotion out of a certain experience by creating a memory of it. This way, the emotion itself is no longer active.  This mechanism fulfils an important role because when we don’t process our emotions, especially negative ones, this increases personal worry and anxiety. In fact, severe REM sleep-deprivation is increasingly correlated to the development of mental disorders. In short, dreams help regulate traffic on that fragile bridge which connects our experiences with our emotions and memories.

Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter @garethideas .

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Dreaming is influenced by the consolidation of memories during sleep.

Why do we dream?

by Shafaq Zia | August 1, 2022 May 24, 2023

Categories: Cognitive Neuroscience , Ask the Brain

As part of our Ask the Brain series, science writer Shafaq Zia answers the question, “Why do we dream?”

One night, Albert Einstein dreamt that he was walking through a farm where he found a herd of cows against an electric fence. When the farmer switched on the fence, the cows suddenly jumped back, all at the same time. But to the farmer’s eyes, who was standing at the other end of the field, they seemed to have jumped one after another, in a wave formation. Einstein woke up and the Theory of Relativity was born.

Dreaming is one of the oldest biological phenomena; for as long as humans have slept, they’ve dreamt. But through most of our history, dreams have remained mystified, leaving scientists, philosophers, and artists alike searching for meaning.

In many aboriginal cultures, such as the Esa Eja community in Peruvian Amazon, dreaming is a sacred practice for gaining knowledge, or solving a problem, through the dream narrative. But in the last century or so, technological advancements have allowed neuroscientists to take up dreams as a matter of scientific inquiry in order to answer a much-pondered question — what is the purpose of dreaming?

Falling asleep

The human brain is a fascinating place. It is composed of approximately 80 billion neurons and it is their combined electrical chatter that generates oscillations known as brain waves. There are five types of brain waves —  alpha, beta, theta, delta, and gamma — that each indicate a different state between sleep and wakefulness.

Using EEG, a test that records electrical activity in the brain, scientists have identified that when we’re awake, our brain emits beta and gamma waves. These tend to have a stimulating effect and help us remain actively engaged in mental activities.

But during the transition to sleep, the number of beta waves lowers significantly and the brain produces high levels of alpha waves. These waves regulate attention and help filter out distractions. A recent study led by McGovern Institute Director Robert Desimone, showed that people can actually enhance their attention by controlling their own alpha brain waves using neurofeedback training. It’s unknown how long these effects might last and whether this kind of control could be achieved with other types of brain waves, but the researchers are now planning additional studies to explore these questions.

Alpha waves are also produced when we daydream, meditate, or listen to the sound of rain. As our minds wander, many parts of the brain are engaged, including a specialized system called the “default mode network.” Disturbances in this network, explains Susan Whitfield-Gabrieli, a professor of psychology at Northeastern University and a McGovern Institute research affiliate, have been linked to various brain disorders including schizophrenia, depression and ADHD. By identifying the brain circuits associated with mind wandering, she says, we can begin to develop better treatment options for people suffering from these disorders.

Finally, as we enter a dreamlike state, the prefrontal cortex of the brain, responsible for keeping impulses in check, slowly grows less active. This is when there’s a spur in theta waves that leads to an unconstrained window of consciousness; there is little censorship from the mind, allowing for visceral dreams and creative thoughts.

The dreaming brain

“Every time you learn something, it happens so quickly,” said Dheeraj Roy, postdoctoral fellow in Guoping Feng’s lab at the McGovern Institute. “The brain is continuously recording information, but how do you take a break and then make sense of it all?”

This is where dreams come in, says Roy. During sleep, newly-formed memories are gradually stabilized into a more permanent form of long-term storage in the brain. Dreaming, he says, is influenced by the consolidation of these memories during sleep. Most dreams are made up of experiences, thoughts, emotion, places, and people we have already encountered in our lives. But, during dreaming, bits and pieces of these memories seem to be reorganized to create a particularly bizarre scenario: you’re talking to your sister when it suddenly begins to rain roses and you’re dancing at a New Year’s party.

This re-organization may not be so random; as the brain is processing memories, it pulls together the ones that are seemingly related to each other. Perhaps you dreamt of your sister because you were at a store recently where a candle smelt like her rose-scented perfume, which reminded you of the time you made a new year resolution to spend less money on flowers.

Some brain disorders, like Parkinson’s disease, have been associated with vivid, unpleasant dreams and erratic brain wave patterns. Researchers at the McGovern Institute hope that a better understanding of mechanics of the brain – including neural circuits and brain waves – will help people with Parkinson’s and other brain disorders.

So perhaps dreams aren’t instilled with meaning, symbolism, and wisdom in the way we’ve always imagined, and they simply reflect important biological processes taking place in our brain. But with all that science has uncovered about dreaming and the ways in which it links to creativity and memory, the magical essence of this universal human experience remains untainted.

Do you have a question for The Brain? Ask it here .

What is consciousness?

For people who speak many languages, there’s something special about their native tongue

Exposure to different kinds of music influences how the brain interprets rhythm

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Explaining Why Dreams and Goals Are Valuable

Table of contents, fueling aspirations and cultivating potential, guiding lights in the journey of life, building resilience and overcoming challenges, catalysts for societal progress and innovation, conclusion: the heartbeat of human ambition.

• Dweck, C. S. (2006). Mindset: The new psychology of success. Random House Incorporated.
• Latham, G. P., & Locke, E. A. (2007). New developments in and directions for goal-setting research. European Psychologist , 12(4), 290-300.

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“Dreaming is so ubiquitous across mammals and even birds that there must be a good reason for it,” Erik Hoel says. Illustration: iStock

A New Theory for Why We Dream

Tufts researcher Erik Hoel draws on machine learning and evolutionary science in his hypothesis about our nightly visits to dreamland

What’s the point of dreams? We all have them, for hours each day of our lives, even if we don’t remember. Plenty of mammals and birds dream, too. When you see Fido sound asleep with his eyes rapidly moving, his paws twitching, you know for sure that he’s in dreamland.

Lots of theories have been offered: dreams are used to regulate emotion, like dealing with fears; to consolidate memory, replaying things from your day to help remember them; to solve, or on the other hand to forget, real-world problems. Another theory suggests they help the brain predict its own future states.

None of those theories seem quite right to Erik Hoel, a research assistant professor at Tufts’ Allen Discovery Center who studies consciousness, modeling the relationships between experiences and brain states.

In his research, Hoel works with artificial neural networks—machine learning. Think of Deep Mind, the Google artificial intelligence program that beat the best human players at the almost infinitely complex Japanese strategy game Go.  

It turns out that when such machine learning programs do the same task again and again, they can become “overfit”—able to do that one thing really well, but not to learn lessons and create general knowledge that can be applied to different tasks. To prevent that, programmers often introduce random variables, or noise in the data.

In essence, that’s what Hoel thinks our brains are doing when we dream: breaking the cycle of repetitive daily tasks—filling out spreadsheets, delivering mail, tightening pipe fittings—with an infusion of discord, keeping our brains fit.

Have you ever had a problem that just seemed to defy solution? You think and think, but you remain stuck. Then you go to bed, wake up the next morning, and presto, the solution appears. It might well be, Hoel would say, that your thinking was overfitted for the task—just like a machine learning program in need of disruption.

“This fits with anecdotal reports of plateauing in terms of performance on a task, like a video game, only to sleep and have increased performance the next day,” Hoel says. “There is also the long-standing traditional association between dreams and creativity.”

He recently published a paper on what he calls the overfitted brain hypothesis, and it’s been garnering attention in the press—it was the cover story for a recent issue of New Scientist magazine.

The Evolution of a Purpose

How Hoel came to the theory surprisingly begins not with neuroscience, but fiction.

When he was young, he loved reading. His mother ran the bookstore Jabberwocky in Newburyport, Mass., and he spent a lot of time there, like the proverbial kid in a candy store, immersed in fictional worlds. He always wanted to be a writer, but ended up studying cognitive science at Hampshire College, and went on to get a Ph.D. in neuroscience. (He did become a fiction writer, too: his novel The Revelations will be published by the Overlook Press in early April.)

His focus as a student was consciousness, but his love of reading also made him wonder why people are so drawn to reading novels, “which always struck me from a scientific perspective as kind of a very strange activity,” he says. “Fictions are essentially lies—there’s no such thing as Hogwarts. Harry Potter never went there. It’s the opposite of facts.”

Fiction has all sorts of purposes—aesthetic, emotional, even political—but probably also has an evolutionary role, Hoel says. “I think that one could argue that there is a sort of deep biological need for fictions in humans,” he says. Just look at all the TV shows, novels, movies, and video games we consume for an ungodly amount of our waking hours. Those diversions “actually serve deep down some sort of fundamental purpose,” he says.

He soon started seeing links between fiction and dreaming. Take the short stories by Jorge Borges, Hoel says. They are rife with narrative and yet quite otherworldly at the same time—just like dreams. It made him think there must be some evolved purpose of dreaming, a function seen across many species of animals.

He soon started to research sleep and dreaming. But looking closely at the scientific literature about dreaming, he came away with more questions than answers. One prominent recent theory says dreams are created for memory consolidation; but why, Hoel asks, do the dreams so rarely actually mimic those memories? Another says that dreams are for emotion processing, but there’s little empirical evidence for it.

One fact that many dream theories also overlook is that while reptiles and many other animals don’t dream, mammals and birds apparently do. “Dreaming is so ubiquitous across mammals and even birds that there must be a good reason for it,” he says.

It’s widely noted in neuroscience that many traits are highly conserved, meaning that brains seem to operate in much the same way across the animal kingdom, Hoel says. The human brain, while “basically getting more bang for your buck in terms of space and having some more frontal and prefrontal regions, is not significantly different in its neuroanatomy from a canine’s,” he points out.

It’s also true, Erik Hoel says, that “evolution is a great multitasker, so I’d be surprised if there’s just one absolute reason for dreaming and no other reason.”

So what does differentiate mammals from reptiles? “Mothers,” says Hoel. “When an iguana is born, nature’s basically just booting up the iguana program—almost everything is just innate for them.” Reptiles therefore don’t actively learn. On the other hand, young mammals learn from their moms (and dads, too) as they develop and are cared for.

It’s unsurprising, Hoel says, that the creatures that have to learn to survive have the most pronounced dreaming and signs of dreaming. It’s likely a sign of dreaming’s evolutionary importance for learning—and survival.

The Human Secret

While metaphors of brains as computers is a bit overdone, Hoel says, in this case, reversing the metaphor to say that brains are like neural networks is close to the mark. After all, he says, those neural networks were designed by engineers to mimic human circuitry.

The overlap between how humans dream, and how machine learning experts avoid pure memorization and help programs transfer knowledge from one problem to others “lends credence to the idea that the evolved function of dreaming is for precisely these purposes,” he says. “It seems that the most effective way to trigger dreams about something is to have subjects perform repetitively on a novel task like Tetris, likely because the visual system has become overfitted to the task.”

Sleep is widely known to have a restorative effect—just try going without it for a day or two and see how well you function. Precisely how that works is not completely known. Current thinking is that sleep evolved as some sort of metabolic housekeeping activity—at one stage of sleep, the cerebral spinal fluid essentially flushes waste products through the lymphatic system.

But dreaming seems to happen during other parts of sleep, and apparently occurs more than we realize; we tend to remember our dreams only if we wake in their midst. Hoel’s theory is that dreaming is an exaptation, a trait that evolved for one purpose but later takes on others.

In this case, he says, “sleep evolved for molecular housekeeping purposes, and only when brains had to significantly learn during the organism’s lifetime did the goal of avoiding overfitting and increasing generalization become adaptive.”

Another key feature of Hoel’s theory is that it “takes the phenomenology of dreams seriously.” Our nightly hallucinogenic narratives, “containing fabulist and unusual events,” are exactly what dreams would be if they were fulfilling the role Hoel proposes—adding noise to the thinking system.

“The point of dreams is the dreams themselves, since they provide departures away from the statistically-biased input of an animal’s daily life, which can therefore increase performance,” he says. “It may seem paradoxical, but a dream of flying may actually help you keep your balance running.”

Have you ever had a problem that just seemed to defy solution? You think and think, but you remain stuck. Then you go to bed, wake up the next morning, and presto, the solution appears. It might well be, Hoel would say, that your thinking was overfitted for the task.

And what about dreams that seem to be speaking to us—helping us understand our lives, remember loved ones, or even scare us?

Meaning in dreams, he says, is basically a side effect. “I don’t think dogs are imbuing their dreams with meaning, but they still dream,” he says. “Humans can imbue their dreams with meaning, but dreams should still have a purpose for all mammals who regularly do it,” Hoel says.

It’s also true, he says, that “evolution is a great multitasker, so I’d be surprised if there’s just one absolute reason for dreaming and no other reason.”

Hoel comes back to where he started: fiction. “It is worth considering whether fictions, like novels or films, act as artificial dreams, accomplishing at least some of the same function,” he says.  

His theory, he says, “suggests fictions, and perhaps the arts in general, may actually have an underlying cognitive utility in the form of improving generalization and preventing overfitting.”

The tradition of fiction goes back much further than the first novel, he says—maybe to the first storytelling shamans. “Maybe that’s part of the human secret—we export some of our learning finessing outside of the body, so that you don’t have to just do it through dreams,” he says. “You can do it through these artificial dreams that maybe even are more impactful because they’re so well structured.”

Mixing Science and Fiction in a Literary Novel

Tufts Researchers Discover New Function Performed by Nearly Half of Brain Cells

Stem Cells and Silk Make a New Way to Study the Brain

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Dreams and Dreaming

Dreams and dreaming have been discussed in diverse areas of philosophy ranging from epistemology to ethics, ontology, and more recently philosophy of mind and cognitive science. This entry provides an overview of major themes in the philosophy of sleep and dreaming, with a focus on Western analytic philosophy, and discusses relevant scientific findings.

1.1 Cartesian dream skepticism

1.2 earlier discussions of dream skepticism and why descartes’ version is special, 1.3 dreaming and other skeptical scenarios, 1.4 descartes’ solution to the dream problem and real-world dreams, 2.1 are dreams experiences, 2.2 dreams as instantaneous memory insertions, 2.3 empirical evidence on the question of dream experience, 2.4 dreams and hallucinations, 2.5 dreams and illusions, 2.6 dreams as imaginative experiences, 2.7 dreaming and waking mind wandering, 2.8 the problem of dream belief, 3.1 dreaming as a model system and test case for consciousness research, 3.2 dreams, psychosis, and delusions, 3.3 beyond dreams: dreamless sleep experience and the concepts of sleep, waking, and consciousness, 4. dreaming and the self, 5. immorality and moral responsibility in dreams, 6.1 the meaning of dreams, 6.2 the functions of dreaming, 7. conclusions, other internet resources, related entries, 1. dreams and epistemology.

Dream skepticism has traditionally been the most famous and widely discussed philosophical problem raised by dreaming (see Williams 1978; Stroud 1984). In the Meditations , Descartes uses dreams to motivate skepticism about sensory-based beliefs about the external world and his own bodily existence. He notes that sensory experience can also lead us astray in commonplace sensory illusions such as seeing things as too big or small. But he does not think such cases justify general doubts about the reliability of sensory perception: by taking a closer look at an object seen under suboptimal conditions, we can easily avoid deception. By contrast, dreams suggest that even in a seemingly best-case scenario of sensory perception (Stroud 1984), deception is possible. Even the realistic experience of sitting dressed by the fire and looking at a piece of paper in one’s hands (Descartes 1641: I.5) is something that can, and according to Descartes often does, occur in a dream.

There are different ways of construing the dream argument. A strong reading is that Descartes is trapped in a lifelong dream and none of his experiences have ever been caused by external objects (the Always Dreaming Doubt ; see Newman 2019). A weaker reading is that he is just sometimes dreaming but cannot rule out at any given moment that he is dreaming right now (the Now Dreaming Doubt ; see Newman 2019). This is still epistemologically worrisome: even though some of his sensory-based beliefs might be true, he cannot determine which these are unless he can rule out that he is dreaming. Doubt is thus cast on all of his beliefs, making sensory-based knowledge slip out of reach.

Cartesian-style skeptical arguments have the following form (quoted from Klein 2015):

• If I know that p , then there are no genuine grounds for doubting that p .
• U is a genuine ground for doubting that p .
• Therefore, I do not know that p .

If we apply this to the case of dreaming, we get:

• If I know that I am sitting dressed by the fire, then there are no genuine grounds for doubting that I am really sitting dressed by the fire.
• If I were now dreaming, this would be a genuine ground for doubting that I am sitting dressed by the fire: in dreams, I have often had the realistic experience of sitting dressed by the fire when I was actually lying undressed in bed!
• Therefore, I do not know that I am now sitting dressed by the fire.

Importantly, both strong and weak versions of the dream argument cast doubt only on sensory-based beliefs, but leave other beliefs unscathed. According to Descartes, that 2+3=5 or that a square has no more than 4 sides is knowable even if he is now dreaming:

although, in truth, I should be dreaming, the rule still holds that all which is clearly presented to my intellect is indisputably true. (Descartes 1641: V.15)

By Descartes’ lights, dreams do not undermine our ability to engage in the project of pure, rational enquiry (Frankfurt 1970; but see Broughton 2002).

Dream arguments have been a staple of philosophical skepticism since antiquity and were so well known that in his objections to the Meditations , Hobbes (1641) criticized Descartes for not having come up with a more original argument. Yet, Descartes’ version of the problem, more than any other, has left its mark on the philosophical discussion.

Earlier versions tended to touch upon dreams just briefly and discuss them alongside other examples of sensory deception. For example, in the Theaetetus (157e), Plato has Socrates discuss a defect in perception that is common to

dreams and diseases, including insanity, and everything else that is said to cause illusions of sight and hearing and the other senses.

This leads to the conclusion that knowledge cannot be defined through perception.

Dreams also appear in the canon of standard skeptical arguments used by the Pyrrhonists. Again, dreams and sleep are just one of several conditions (including illness, joy, and sorrow) that cast doubt on the trusthworthiness of sensory perception (Diogenes Laertius, Lives of Eminent Philosophers; Sextus Empiricus, Outlines of Pyrrhonism) .

Augustine ( Against the Academics ; Confessions) thought the dream problem could be contained, arguing that in retrospect, we can distinguish both dreams and illusions from actual perception (Matthew 2005: chapter 8). And Montaigne ( The Apology for Raymond Sebond ) noted that wakefulness itself teems with reveries and illusions, which he thought were even more epistemologically worrisome than nocturnal dreams.

Descartes devoted much more space to the discussion of dreaming and cast it as a unique epistemological threat distinct from both waking illusions and evil genius or brain-in-a-vat-style arguments. His claim that he has often been deceived by his dreams implies he also saw dreaming as a real-world (rather than merely hypothetical) threat.

This is further highlighted by the intimate, first-person style of the Meditations . Their narrator is supposed to exemplify everyone’s epistemic situation, illustrating the typical defects of the human mind. Readers are further drawn in by Descartes’ strategy of moving from commonsense examples towards more sophisticated philosophical claims (Frankfurt 1970). For example, Descartes builds up towards dream skepticism by first considering familiar cases of sensory illusions and then deceptively realistic dreams.

Finally, much attention has been devoted to several dreams Descartes reportedly had as a young man. Some believe these dreams embodied theoretical doubts he developed in the Discourse and Meditations (Baillet 1691; Leibniz 1880: IV; Cole 1992; Keefer 1996). Hacking (2001:252) suggests that for Descartes, dream skepticism was not just a philosophical conundrum but a source of genuine doubt. There is also some discussion about the dream reports’ authenticity (Freud 1940; Cole 1992; Clarke 2006; Browne 1977).

In the Meditations , after discussing the dream argument, Descartes raises the possibility of an omnipotent evil genius determined to deceive us even in our most basic beliefs. Contrary to dream deception, Descartes emphasizes that the evil genius hypothesis is a mere fiction. Still, it radicalizes the dream doubt in two respects. One, where the dream argument left the knowability of certain general truths intact, these are cast in doubt by the evil genius hypothesis . Two, where the dream argument, at least on the weaker reading, involves just temporary deception, the evil genius has us permanently deceived.

One modernized version, the brain-in-a-vat thought experiment, says that if evil scientists placed your brain in a vat and stimulated it just right, your conscious experience would be exactly the same as if you were still an ordinary, embodied human being (Putnam 1981). In the Matrix -trilogy (Chalmers 2005), Matrixers live unbeknownst to themselves in a computer simulation. Unlike the brain-in-a-vat , they have bodies that are kept alive in pods, and flaws in the simulation allow some of them to bend its rules to their advantage.

Unlike dream deception, which is often cast as a regularly recurring actuality (cf. Windt 2011), brain-in-a-vat-style arguments are often thought to be merely logically or nomologically possible. However, there might be good reasons for thinking that we actually live in a computer simulation (Bostrom 2003), and if we lend some credence to radical skeptical scenarios, this may have consequences for how we act (Schwitzgebel 2017).

Even purely hypothetical skeptical scenarios may enhance their psychological force by capitalizing on the analogy with dreams. Clark (2005) argues that the Matrix contains elements of “industrial-strength deception” in which both sensory experience and intellectual functioning are exactly the same as in standard wake-states, whereas other aspects are more similar to the compromised reasoning and bizarre shifts that are the hallmark of dreams.

At the end of the Sixth Meditation , Descartes suggests a solution to the dream problem that is tied to a reassessment of what it is like to dream. Contrary to his remarks in the First Meditation , he notes that dreams are only rarely connected to waking memories and are often discontinuous, as when dream characters suddenly appear or disappear. He then introduces the coherence test:

But when I perceive objects with regard to which I can distinctly determine both the place whence they come, and that in which they are, and the time at which they appear to me, and when, without interruption, I can connect the perception I have of them with the whole of the other parts of my life, I am perfectly sure that what I thus perceive occurs while I am awake and not during sleep. (Meditation VI. 24)

For all practical purposes, he has now found a mark by which dreaming and waking can be distinguished (cf. Meditation I.7), and even if the coherence test is not fail-safe, the threat of dream deception has been averted.

Descartes’ remarks about the discontinuous and ad hoc nature of many dreams are backed up by empirical work on dream bizarreness (see Hobson 1988; Revonsuo & Salmivalli 1995). Still, many of his critics were not convinced this helped his case against the skeptic. Even if Descartes’ revised phenomenological description characterizes most dreams, one might occasionally merely dream of successfully performing the test (Hobbes 1641), and in some dreams, one might seem to have a clear and distinct idea but this impression is false (Bourdin 1641). Both the coherence test and the criterion of clarity and distinctness would then be unreliable.

How considerations of empirical plausibility impact the dream argument continues to be a matter of debate. Grundmann (2002) appeals to scientific dream research to introduce an introspective criterion: when we introspectively notice that we are able to engage in critical reflection, we have good reason to think that we are awake and not dreaming. However, this assumes critical reasoning to be uniformly absent in dreams. If attempts at critical reasoning do occur in dreams and if they generally tend to be corrupted, the introspective criterion might again be problematic (Windt 2011, 2015a). There are also cases in which even after awakening, people mistake what was in fact a dream for reality (Wamsley et al. 2014). At least in certain situations and for some people, dream deception might be a genuine cause of concern (Windt 2015a).

2. The ontology of dreams

In what follows, the term “conscious experience” is used as an umbrella term for the occurrence of sensations, thoughts, impressions, emotions etc. in dreams (cf. Dennett 1976). These are all phenomenal states: there is something it is like to be in these states for the subject of experience (cf. Nagel 1974). To ask about dream experience is to ask whether it is like something to dream while dreaming, and whether what it is like is similar to (or relevantly different from) corresponding waking experiences.

Cartesian dream skepticism depends on a seemingly innocent background assumption: that dreams are conscious experiences. If this is false, then dreams are not deceptive experiences during sleep and we cannot be deceived, while dreaming, about anything at all. Whether dreams are experiences is a major question for the ontology of dreams and closely bound up with dream skepticism.

The most famous argument denying that dreams are experiences was formulated by Norman Malcolm (1956, 1959). Today, his position is commonly rejected as implausible. Still, it set the tone for the analysis of dreaming as a target phenomenon for philosophy of mind.

For Malcolm, the denial of dream experience followed from the conceptual analysis of sleep: “if a person is in any state of consciousness it logically follows that he is not sound asleep” (Malcolm 1956: 21). Following some remarks of Wittgenstein’s (1953: 184; see Chihara 1965 for discussion), Malcolm claimed

the concept of dreaming is derived, not from dreaming, but from descriptions of dreams, i.e., from the familiar phenomenon that we call “telling a dream”. (Malcolm 1959:55)

Malcolm argued that retrospective dream reports are the sole criterion for determining whether a dream occurred and there is no independent way of verifying dream reports. While first-person, past-tense psychological statements (such as “I felt afraid”) can at least in principle be verified by independent observations (but see Canfield 1961; Siegler 1967; Schröder 1997), he argued dream reports (such as “in my dream, I felt afraid”) are governed by different grammars and merely superficially resemble waking reports. In particular, he denied dream reports imply the occurrence of experiences (such as thoughts, feelings, or judgements) in sleep:

If a man had certain thoughts and feelings in a dream it no more follows that he had those thoughts and feelings while asleep, than it follows from his having climbed a mountain in a dream that he climbed a mountain while asleep. (Malcolm 1959/1962: 51–52)

What exactly Malcolm means by “conscious experience” is unclear. Sometimes he seems to be saying that conscious experience is conceptually tied to wakefulness (Malcolm 1956); other times he claims that terms such as mental activity or conscious experience are vague and it is senseless to apply them to sleep and dreams (Malcolm 1959: 52).

Malcolm’s analysis of dreaming has been criticized as assuming an overly strict form of verificationism and a naïve view of language and conceptual change. A particularly counterintuitive consequence of his view is that there can be no observational evidence for the occurrence of dreams in sleep aside from dream reports. This includes behavioral evidence such as sleepwalking or sleeptalking, which he thought showed the person was partially awake; as he also thought dreams occur in sound sleep, such sleep behaviors were largely irrelevant to the investigation of dreaming proper. He also claimed adopting a physiological criterion of dreaming (such as EEG measures of brain activity during sleep) would change the concept of dreaming, which he argued was tied exclusively to dream reporting. This claim was particularly radical as it explicitly targeted the discovery of REM sleep and its association with dreaming (Dement & Kleitman 1957), which is commonly regarded as the beginning of the science of sleep and dreaming. Malcolm’s position was that the very project of a science of dreaming was misguided.

Contra Malcolm, most assume that justification does not depend on strict criteria with the help of which the truth of a statement can be determined with absolute certainty, but “on appeals to the simplicity, plausibility, and predictive adequacy of an explanatory system as a whole” (Chihara & Fodor 1965: 197). In this view, behavioral and/or physiological evidence can be used to verify dream reports (Ayer 1960) and the alleged principled difference between dream reports and other first-person, past-tense psychological sentences (Siegler 1967; Schröder 1997) disappears.

Putnam noted that Malcolm’s analysis of the concept of dreaming relies on the dubious idea that philosophers have access to deep conceptual truths that are hidden to laypeople:

the lexicographer would undoubtedly perceive the logical (or semantical) connection between being a pediatrician and being a doctor, but he would miss the allegedly “logical” character of the connection between dreams and waking impressions. […] this “depth grammar” kind of analyticity (or “logical dependence”) does not exist. (Putnam 1962 [1986]: 306)

Nagel argued that even if one accepts Malcolm’s analysis of the concept of dreaming,

it is a mistake to invest the demonstration that it is impossible to have experiences while asleep with more import than it has. It is an observation about our use of the word “experience”, and no more. It does not imply that nothing goes on in our minds while we dream. (Nagel 1959: 114)

Whether dream thoughts, feelings or beliefs should count as real instances of their kind now becomes an open question, and in any case there is no conceptual contradiction involved in saying one has experiences while asleep and dreaming.

To ask about dream experience is also to ask whether there is something it is like to dream during sleep as opposed to there just being something it is like to remember dreaming after awakening. Dennett’s (1976, 1979) cassette theory says dreams are the product of instantaneous memory insertion at the moment of the awakening, as if a cassette with pre-scripted dreams had been inserted into memory, ready for replay. Dennett claims the cassette theory and the view that dreams are experiences can deal equally well with empirical evidence for instance on the relationship between dreaming and REM sleep. The cassette theory is preferable because it is more parsimonious, positing only an unconscious dream composition process rather than an additional conscious presentation process in sleep. For Dennett, the important point is that it is impossible to distinguish between the two rival theories based on dream recall; the question of dream experience should be settled by independent empirical evidence.

While Dennett shares Malcolm’s skepticism about dream experience, this latter claim is diametrically opposed to Malcolm’s rejection of a science of dreaming. For Dennett, the unreliability of dream recall also is not unique, but exemplifies a broader problem with memory reports: we generally cannot use retrospective recall to distinguish conscious experience from memory insertion (Dennett 1991; see also Emmett 1978).

An earlier and much discussed (Binz 1878; Goblot 1896; Freud 1899; Hall 1981; Kramer 2007:22–24) version of Dennett’s cassette theory goes back to Maury’s (1861) description of a long and complex dream about the French revolution that culminated in his execution at the guillotine, at which point Maury suddenly awoke to find that the headboard had fallen on his neck. Because the dream seemed to systematically build up to this dramatic conclusion, which in turn coincided with a sudden external event, he suggested that such cases were best explained as instantaneous memory insertions experienced at the moment of awakening. Similarly, Gregory (1916) described dreams are psychical explosions occurring at the moment of awakening.

The trustworthiness of dream reports continues to be contentious. Rosen (2013) argues that dream reports are often fabricated and fail to accurately describe experiences occurring during sleep. By contrast, Windt (2013, 2015a) argues that dream reports can at least under certain conditions (such as in laboratory studies, when dreams are reported immediately after awakening by trained participants) be regarded as trustworthy sources of evidence with respect to previous experience during sleep.

Unlike Malcolm, many believe that whether dreams are experiences is an empirical question; and unlike Dennett, the predominant view is that the empirical evidence does indeed support this claim (Flanagan 2000; Metzinger 2003; Revonsuo 2006; Rosen 2013; Windt 2013, 2015a).

A first reason for thinking that dreams are experiences during sleep is the relationship between dreaming and REM (rapid eye movement) sleep. Researchers in the 1950s discovered that sleep is not a uniform state of rest and passivity, but there is a sleep architecture involving different stages of sleep that is relatively stable both within and across individuals (Aserinsky & Kleitman 1953, 1955; Dement & Kleitman 1957). Following sleep onset, periods of non-REM (or NREM) sleep including slow wave sleep (so called because of the presence of characteristic slow-wave, high-voltage EEG activity) are followed by periods of high-frequency, low-voltage activity during REM sleep. EEG measures from REM sleep strongly resemble waking EEG. REM sleep is additionally characterized by rapid eye movements and a near-complete loss of muscle tone (Dement 1999: 27–50; Jouvet 1999).

The alignment between conscious experience on the one hand and wake-like brain activity and muscular paralysis on the other hand would seem to support the experiential status of dreams as well as explain the outward passivity that typically accompanies them. Reports of dreaming are in fact much more frequent following REM (81.9%) than NREM sleep awakenings (43%; Nielsen 2000). REM reports tend to be more elaborate, vivid, and emotionally intense, whereas NREM reports tend to be more thought-like, confused, non-progressive, and repetitive (Hobson et al. 2000). These differences led to the idea that REM sleep is an objective marker of dreaming (Dement & Kleitman 1957; Hobson 1988: 154).

Attempts to identify dreaming with mental activity during REM sleep have not, however, been successful, and many now hold that dreams can occur in all stages of sleep (e.g., Antrobus 1990; Foulkes 1993b; Solms 1997, 2000; Domhoff 2003; Nemeth & Fazekas 2018). In recent years there has been renewed interest in NREM sleep for the study of dreaming (Noreika et al. 2009; Siclari et al. 2013, 2017). This suggests the inference from the physiology of REM sleep to the phenomenology of dreaming is not straightforward.

A second line of evidence comes from lucid dreams, or dreams in which one knows one is dreaming and often has some level of dream control (Voss et al. 2013; Voss & Hobson 2015; Baird et al. 2019). The term lucid dreaming was coined by van Eeden (1913), but Aristotle ( On Dreams ) already noted that one can sometimes be aware while dreaming that one is dreaming.

Scientific evidence that lucid dreaming is real and a genuine sleep phenomenon comes from laboratory studies (Hearne 1978; LaBerge et al. 1981) showing lucid dreamers can use specific, pre-arranged patterns of eye movements (e.g., right-left-right-left) to signal in real-time that they are now lucid and engaging in dream experiments. These signals are clearly identifiable on the EOG and suggest a correspondence between dream-eye movements and real-eye movements (as predicted by the so-called scanning hypothesis ; see Dement & Kleitman 1957; Leclair-Visonneau et al. 2010). Retrospective reports confirm that the dreamer really was lucid and signalled lucidity (Dresler et al. 2012; Stumbrys et al. 2014).

Signal-verified lucid dreams have been used to study muscular activity accompanying body movements in dreams (Erlacher et al. 2003; Dresler et al. 2011), for advanced EEG analysis of brain activity during lucid dreaming (Voss et al. 2009), and imaging studies (Dresler et al. 2011, 2012). Eye signals can also be used to measure the duration of different activities performed in lucid dreams; contrary to the cassette theory, lucid dreams have temporal extension and certain dream actions even seem to take slightly longer than in waking (Erlacher et al. 2014). There have also been attempts to induce lucidity through non-invasive electrical stimulation during sleep (Stumbrys et al. 2013; Voss et al. 2014). The combination of signal-verified lucid dreaming with volitional control over dream content, retrospective report, and objective sleep measures has been proposed to provide controlled conditions for the study of conscious experience in sleep and a new methodology for investigating the relationship between conscious experience and neurophysiological processes (Baird et al.2019).

A third line of evidence (Revonsuo 2006: 77) comes from dream-enactment behavior (Nielsen et al. 2009), most prominently in patients with REM-sleep behavior disorder (RBD; Schenck & Mahowald 1996; Schenck 2005; Leclair-Visonneau et al. 2010). Due to a loss of the muscular atonia that accompanies REM sleep in healthy subjects, these patients show complex, seemingly goal-directed outward behaviors such as running or fighting off an attacker during REM sleep. Retrospective dream reports often match these behaviors, suggesting that patients literally act out their dreams during sleep.

While persuasive, these lines of evidence might not satisfy skeptics about dream experience. They might worry that results from lucid dreaming and dream enactment do not generalize to ordinary, non-lucid dreams; they might also construe alternative explanations that do not require conscious experience in sleep. There are also methodological concerns, for instance about how closely sleep-behaviors actually match dream experience. A key issue is that to support the experiential status of dreams, evidence from sleep polysomnography, signal verified lucid dreams, or sleep behavior requires convergence with retrospective dream reports. This means trusting dream reports is built into any attempt to empirically resolve the question of dream experience – which then invites the familiar skeptical concerns. Again, an anti-skeptical strategy may be to appeal to explanatory considerations. In this view, the convergence of dream reports and objective polysomnographic or behavioral observations is best explained by the assumption that dreams are experiences in sleep, and this assumption is strengthened by further incoming findings. This strategy places dream reports at the center of scientific dream research while avoiding the contentious claim that their trustworthiness, and with it the experiential status of dreams, can be demonstrated conclusively by independent empirical means (Windt 2013, 2015a).

Even where philosophers agree dreams are experiences, they often disagree on how exactly to characterize dreaming relative to wake-state psychological terms. Often, questions about the ontology of dreaming intersect with epistemological issues. Increasingly, they also incorporate empirical findings.

The standard view is that dreams have the same phenomenal character as waking perception in that they seemingly put us in contact with mind-independent objects, yet no such object is actually being perceived. This means dreams count as hallucinations in the philosophical sense (Crane & French 2017; Macpherson 2013). Even if, in a particularly realistic dream, my visual experience was exactly as it would be if I were awake (I could see my bedroom, my hands on the bed sheets, etc.), as long as my eyes were closed during the episode, I would not, literally, be seeing anything.

There is some controversy in the psychological literature about whether dreams should be regarded as hallucinations. Some believe the term hallucination should be reserved for clinical contexts and wake-state pathologies (Aleman & Larøi 2008: 17; but see ffytche 2007; ffytche et al. 2010).

The view that dreams involve hallucinations is implicit in Descartes’ assumption that even when dreaming,

it is certain that I seem to see light, hear a noise, and feel heat; this cannot be false, and this is what in me is properly called perceiving ( sentire ). (Descartes 1641: II.9)

It also lies at the heart of Aristotle’s ( On Dreams ) assumption that dreams result from the movements of the sensory organs that continue even after the original stimulus has ceased. He believed that in the silence of sleep, these residual movements result in vivid sensory imagery that is subjectively indistinguishable from genuine perception (see also Dreisbach 2000; Barbera 2008).

The assumption of phenomenological equivalence between dream and waking experience can also be found in Berkeley’s (1710: I.18) idealist claim that the existence of external bodies is not necessary for the production of vivid, wake-like perceptual experience. Similarly, Russell defended sense-data theory by noting that in dreams,

I have all the experiences that I seem to have; it is only things outside my mind that are not as I believe them to be while I am dreaming. (Russell 1948: 149–150)

Elsewhere, he argued dreams and waking life

must be treated with equal respect; it is only by some reality not merely sensible that dreams can be condemned. (Russell 1914: 69)

Hume was less clear on this matter, proposing that dreams occupy an intermediate position between vivid and largely non-voluntary sensory impressions and ideas, or “the faint images of previous impressions in thinking and reasoning” (Hume 1739: 1.1.1.1). On the one hand, as mere creatures of the mind, Hume wanted to categorize dreams as ideas. On the other hand, he acknowledged that in sleep, “our ideas can approach the vivacity of sensory impressions” (Hume 1739: 1.1.1.1). Dreams do not fit comfortably into Hume’s attempt to draw a dichotomous distinction between impressions, including perception, and ideas, including sensory imagination (Ryle 1949; Waxman 1994; Broughton 2006).

Phenomenologists often focus not so much on the quality of dream imagery as on the overall character of experience, noting that dreams are experienced as reality; as in waking perception, we simply feel present in a world. This also sets dreams apart from waking fantasy and daydreams (Husserl 1904/1905; Uslar 1964; Conrad 1968; Globus 1987: 89.

At its strongest, the hallucination view claims that dreaming and waking experience are identical in both the quality of sensory imagery and their overall, self-in-a-world structure (Revonsuo 2006: 84). This claim is central to the virtual reality metaphor , according to which consciousness itself is dreamlike and waking perception a kind of online hallucination modulated by the senses (Llinás & Ribary 1994; Llinás & Paré 1991; Revonsuo 2006; Metzinger 2003, 2009).

This seems to be empirically supported. Neuroimaging studies (Dang-Vu et al. 2007; Nir & Tononi 2010; Desseilles et al. 2011) show that the predominance of visual and motor imagery as well as strong emotions in dreams is paralleled by high activation of the corresponding brain areas in REM sleep, which may exceed waking; at the same time, the cognitive deficits often thought to characterize dreams such as the loss of self-awareness, the absence of critical thinking, delusional reasoning, and mnemonic deficits fit in well with the comparative deactivation of frontal areas (Hobson et al. 2000). Hobson (1988, Hobson et al. 2000) has argued that the vivid, hallucinatory character of dreaming results from the fact that in REM sleep, the visual and motor areas are activated in the same way as in waking perception, the sole difference being dreams’ dependence on internal signal generation. Horikawa and colleagues (2013) used neuroimaging data from sleep onset to predict the types of objects described in mentation reports, which they took to support the perceptual equivalence between dreaming and waking.

Generally, versions of the hallucination view that suggest dreams replicate all aspects of waking perception are too vague to be informative. Especially for subtle perceptual activities (such as visual search), we might not know enough about dream phenomenology to make any strong claims (Nielsen 2010). Specifying points of similarity leads to a more informative and precise, but likely also more nuanced view. Dreams are heterogeneous, and some might be more perception-like while others resemble imagination (Windt 2015a). There might also be differences between or even within specific types of imagery. For example, visual imagery might be quite different from touch sensations, which tend to be rare in dreams (Hobson 1988). Visual dream imagery might overall resemble waking perception but lack color saturation, background detail and focus (Rechtschaffen & Buchignani, 1992). Classifying dreams as either hallucinatory or imaginative is further complicated by the fact that there is strong overlap in cortical activity associated with both visual imagery and perception (Zeidman & Maguire, 2016). This means even a strong overlap in cortical activity between, say, visual dream imagery and visual perception does not necessarily set dreaming apart from waking imagination.

This is also true for evidence on eye movements in dreams. LaBerge and colleagues (2018) recently showed that eye tracking of objects is smooth in lucid dreaming and perceiving, but not in imagining. Drawing from this evidence, Rosen (forthcoming) suggests many dreams mimic the phenomenology of interacting with a stable world, including eye movements and visual search. Others argue we should not analogize dream imagery to mind-independent, scannable objects and that eye movements might instead be implicated in the generation of dream imagery (Windt 2018).

Another way to make sense of the claim that dreaming has the same phenomenal character as waking perception is to say some kinds of dream imagery are illusory: they involve misperception of an external object as having different properties than it actually has (cf. Smith 2002; Crane & French 2017). The illusion view disagrees with the hallucination view on whether dreams have a contemporaneous external stimulus source.

The illusion view has fallen out of favor but has a long history. The Ancients believed dreams have bodily sources. This idea underlies the practice of using dreams to diagnose illness, as practiced in the shrines at Epidaurus (Galen On Diagnosis in Dreams ; van de Castle 1994). Aristotle ( On Dreams ) thought some dreams are caused by indigestion, and Hobbes adopted this view, claiming different kinds of dreams could be traced to different bodily sensations. For instance, “lying cold breedeth Dreams of Feare, and raiseth the thought and Image of some fearfull object” (Hobbes 1651: 91).

Appeals to the bodily sources of dreaming became especially popular in the 19 th and early 20 th centuries. Many believed specific dream themes such as flying were linked to sleeping position (Macnish 1838; Scherner 1861; Vold 1910/1912; Ellis 1911) and realizing, in sleep, that one’s feet are not touching the ground (Bergson 1914).

There were also attempts to explain the phenomenology of dreaming by appealing to the absence of outward movement. The lack of appropriate feedback and of movement and touch sensations was thought to cause dreams of being unable to move (Bradley 1894) or of trying but failing to do something (Gregory 1918).

Some proponents of the “ Leibreiztheorie ” (or somatic-stimulus theory) of dreaming attempted to go beyond anecdotal observations to conduct controlled experiments. Weygandt (1893) investigated the influence of various factors including breathing, blood circulation, temperature changes, urge to urinate, sleeping position, and visual or auditory stimulation during sleep on dream content (see Schredl 2010 for details). Singer (1924) proposed experiments on stimulus incorporation in dreams can inform claims on the ontology of dreaming: If dreams are sensations, a particular auditory stimulus should increase the frequency of dreams in nearby sleepers as well as the frequency of sound in their dreams, and it should decrease the range of quality and intensity of these dreams, making them overall more similar and predictable.

Newer studies provide evidence for the incorporation of external stimuli in dreams, including light flashes, sounds, sprays of water applied to the skin (Dement & Wolpert 1958), thermal (Baldridge 1966), electrical (Koulack 1969), and verbal stimuli (Berger 1963; Breger et al. 1971; Hoelscher et al., 1981), as well as blood pressure cuff stimulation on the leg (Nielsen et al. 1995; Sauvageau et al. 1998).

Muscular activity also often leaves its mark on dreams. It occurs throughout sleep but is especially frequent in REM sleep, mostly in the form of twitching but occasionally also in the form of larger, seemingly goal-directed movements (Blumberg 2010; Blumberg & Plumeau 2016). The relation between outward and dream movements is complex: in some cases, outward movements might mirror dream movements, while in others, sensory feedback might prompt dream imagery (Windt 2018).

Generally, it seems external and bodily stimuli can be related to varying degrees to dream and sleep onset imagery (Nielsen 2017; Windt 2018; Windt et al. 2016). Some of these cases appear to fit the concept of illusion, as in when the sound of the alarm clock is experienced, in a dream, as a siren, or when blood pressure cuff inflation on the leg leads to dreams of wearing strange shoes (Windt 2018; for these and other examples, see Nielsen et al. 1995). In other cases, such as when blood pressure cuff stimulation on the leg prompts a dream of seeing someone else’s leg being run over, describing this as illusory misperception might be less straightforward.

Saying that dreams can be prompted by external stimuli and that in some cases these are best described as illusions is different from the stronger claim, sometimes advanced by historical proponents of somatic-stimulus theory, that dreams generally are caused by external or bodily stimuli. As an example of the stronger claim, consider Wundt’s proposal that the

ideas which arise in dreams come, at least to a great extent, from sensations, especially from those of the general sense, and are therefore mostly illusions of fancy, probably only seldom pure memory ideas which hence become hallucinations. (Wundt 1896: 179)

This claim is likely too strong. It is also likely that appeals to external or bodily stimuli on their own cannot fully explain dream imagery, including when and how external stimuli are incorporated in dreams. Sensory incorporation in dreams is often hard to predict and indirect; associated imagery seems related not just to stimulus intensity, but also to short- and long term memories. A full explanation of dream content additionally has to take the cognitive and memory sources of dreaming into account (Windt 2018; Nielsen 2017; cf. Silberer 1919).

The most important rival to the hallucination view is that dreams are imaginative experiences (Liao & Gendler 2019; Thomas 2014). This can mean dream imagery involves imaginings rather than percepts (including hallucinations or illusions; McGinn 2004), that dream beliefs are imaginative and not real beliefs (Sosa 2007), or both (Ichikawa 2008, 2009). An important advantage is that by assimilating dreams to commonplace mental states such as waking fantasy and daydreaming, rather than a rare and often pathological occurrence such as hallucinations, it provides a more unified account of mental life (Stone 1984). However, the reasons for adopting the imagination view are diverse, and dreams have been proposed to resemble imaginings and differ from perception along a number of dimensions (e.g. McGinn 2004, 2005a,b; Thomas 2014). This issue is complicated by the fact that there is little agreement on the definition of imagination and its relation to perception (Kind 2013).

One way is to deny dreams involve presence or the feeling of being in a world, which many believe is central to waking perception. Imagination theorists compare the sense in which we feel present in our dreams to cognitive absorption, as when we are lost in a novel, film, or vivid daydream (Sartre 1940; McGinn 2004; but see Hering 1947; Globus 1987). Some argue that reflexive consciousness or meta-awareness (as in lucid dreams) interrupts cognitive absorption and terminates the ongoing dream (Sartre 1940), essentially denying lucid dreams are possible.

Another issue is whether dreams are subject to the will (Ichikawa 2009). Imagination is often characterized as active and under our control (Wittgenstein 1967: 621, 633), involving “a special effort of the mind” (Descartes 1641: VI, 2), whereas perception is passive. Because dreams just seem to happen to us without being under voluntary control, they present an important challenge for the imagination view. Ichikawa (2009) argues lucid control dreams show dreams are generally subject to the will even where they are not under deliberate control.

Dreams are widely described as more indeterminate than waking perception (James 1890: 47; Stone 1984). In scientific dream research, vagueness is regarded as one of three main subtypes of bizarreness (Hobson 1988; Revonsuo & Salmivalli 1995). An example are dream characters who are identified not by their behavior or looks, but by just knowing (Kahn et al. 2000, 2002; Revonsuo & Tarkko 2002). Dreams are also attention-dependent and lack foreground-background structure (Thompson 2014); while it is tempting to construe the dream world as rich in detail, there is no more to dreams than meets the eye, and many think dream experience is exhausted by what is the focus of selective attention (Hunter 1983; Thompson 2014).

Indeterminacy is also related to the question of whether we dream in color or in black and white. Based on a review of historical and recent studies, Schwitzgebel (2002, 2011) argues there has been a shift in theories on dream color that coincides with the rise first of black-and-white and then color television. He argues it is unlikely that dreams themselves changed from colored to black and white and back to colored, proposing that a change in opinion is a more plausible explanation. Maybe dreams were either black and white or colored all along; or maybe they are indeterminate with respect to color, as may be the case for imagined or fictional objects; were this the case, it would strengthen the imagination view (Ichikawa 2009). Schwitzgebel’s main point is that reports of colored dreaming are unreliable and our opinions about dreams can be mistaken (but see Windt 2013, 2015a). This relates to Schwitzgebel’s (2011; Hurlburt & Schwitzgebel 2007) general skepticism about the reliability of introspection.

The issue of dream color has led to a number of follow-up studies (Schwitzgebel 2003; Schwitzgebel et al. 2006; Murzyn 2008; Schredl et al. 2008; Hoss 2010). They suggest most people dream in color and a small percentage describe grayscale or even mixed dreams (Murzyn 2008) or dreams involving moderate color saturation (Rechtschaffen and Buchignani 1992). Indeterminacy is rarely reported.

The imagination view has consequences for Cartesian dream skepticism. If dream pain does not feel like real pain, there is a fail-safe way to determine whether one is now dreaming: one need only pinch oneself (Nelson 1966; Stone 1984; but see Hodges & Carter 1969; Kantor 1970). As Locke put it,

if our dreamer pleases to try, whether the glowing heat of a glass furnace, be barely a wandering imagination in a drowsy man’s fancy, by putting his hand into it, he may perhaps be wakened into a certainty greater than he could wish, that it is something more than bare imagination. (Locke 1689: IV.XI.8)

If dreaming feels different from waking, this raises the question why we tend to describe dreams in the same terms as waking perception. Maybe this is because most people haven’t thought about these matters and they would find the imagination view plausible if they considered it (Ichikawa 2009). Or maybe

it is just because we all know that dreams are throughout un like waking experiences that we can safely use ordinary expressions in the narration of them. (Austin 1962: 42)

Some authors classify dreams as imaginings while acknowledging they feel like perceiving. For example, Hobbes describes dreams as “the imaginations of them that sleep” (Hobbes 1651: 90), and imagination as a “ decaying sense ” (Hobbes 1651: 88). Yet he also uses the concepts of imagination and fancy to describe perception and argues “their appearance to us is Fancy, the same waking, that dreaming” (Hobbes 1651: 86).

In the scientific literature, the imagination view is complemented by cognitive theories. Foulkes (1978: 5) describes dreaming as a form of thinking with its own grammar and syntax, but allows that dream imagery is sufficently perception-like to deceive us. Domhoff’s neurocognitive model of dreaming (2001, 2003) emphasizes the dependence of dreaming on visuospatial skills and on a network including the association areas of the forebrain. The theory draws from findings on the partial or global cessation of dreaming following brain lesions (cf. Solms 1997, 2000), evidence that dreaming develops gradually and in tandem with visuospatial skills in children (Foulkes 1993a, 1999; but see Resnick et al. 1994), and results from dream content analysis supporting the continuity of dreaming with waking concerns and memories (the so-called continuity hypothesis ; see Domhoff 2001, 2003; Schredl & Hofmann 2003; Schredl 2006; see also Nir & Tononi 2010).

A number of researchers have begun to consider dreaming in the context of theories of mind wandering. Mind wandering is frequent in waking and involves spontaneous thoughts that unfold dynamically and are only weakly constrained by ongoing tasks and environmental demands (Schooler et al. 2011; Smallwood & Schooler 2015; Christoff et al. 2016). Based on phenomenological and neurophysiological similarities, dreams have been proposed to be an intensified form of waking mind wandering (Pace-Schott 2007, 2013; Domhoff 2011; Wamsley 2013; Fox et al. 2013). This basic idea seems to have been anticipated by Leibniz, who noted that the spontaneous formation of visions in dreams surpasses the capacity of our waking imagination (Leibniz, Philosophical Papers and Letters , Vol. I, 177–178).

The analogy between dreams and waking mind wandering has been discussed in the context of cognitive agency. Metzinger (2013a,b, 2015) describes dreams and waking mind wandering as involving a cyclically recurring loss of mental autonomy, or the ability to deliberately control one’s conscious thought processes. Dreams and waking mind wandering are not mental actions but unintentional mental behaviors, comparable to subpersonal processes such as breathing or heartbeat. Because dreaming and waking mind wandering make up a the majority of our conscious mental lives, he argues that cognitive agency and mental autonomy are the exception, not the rule.

This raises the question of how to make sense of lucid control dreams, which involve both meta-awareness and agency. Windt and Voss (2018) argue that in such cases, spontaneous processes including imagery formation co-exist alongside more deliberate, top-down control; they also argue metacognitive insight and control themselves can have spontaneous elements. This suggests spontaneity and control are not opposites, but a more complex account is needed. Possibly, certain dreams and instances of waking mind wandering can be both spontaneous and agentive.

The analogy with mind wandering might help move forward the debate on the ontology of dreaming. In this debate, a common assumption is that dreams can be categorized as either hallucinatory or imaginative. Yet the application of these terms to dreams quickly runs into counterexamples and it is unclear they are mutually exclusive. One option is pluralism (Rosen 2018b), in which some aspects of dreaming are hallucinatory, others imaginative, and yet again others illusory. Another is that dreams are sui generis, combining aspects associated with wake states such as hallucinating, imagining, or perceiving in a novel manner without mimicking them completely. Windt (2015a) proposes that mind wandering, which describes a range of mental states loosely characterized by their spontaneous and dynamic character, might be particularly suitable for the characterization of dreaming precisely because that term leaves open more specific questions on the phenomenology of dreaming, allowing for variation in control, determinacy, and so on. This might be a good starting point for describing what is unique about dreaming while also acknowledging continuities across sleep-wake states and capitalizing on the strengths of the hallucination, illusion, imagination, and cognitive views.

The second strand of the imagination view argues that dream beliefs are not real beliefs, but propositional imaginings. This may or may not be combined with the claim that dream imagery is imaginative rather than perceptual (Sosa 2007; Ichikawa 2009).

Denying that dream beliefs have the status of real beliefs only makes sense before the background of a specific account of what beliefs are and how they are distinguished from other mental states such as delusions or propositional imaginings. For instance, Ichikawa (2009) argues that if we follow interpretationist or dispositionalist accounts of belief, dream beliefs fall short of real beliefs. He claims dream beliefs lack connection with perceptual experience and fail to motivate actions; consequently, they do not have the same functional role as real beliefs. Moreover, we cannot ascribe dream beliefs to a person by observing them lying asleep in bed. Dream beliefs are often inconsistent with longstanding waking beliefs and acquired and discarded without any process of belief revision (Ichikawa 2009).

This analysis of dream beliefs has consequences for skepticism. If dream beliefs are propositional imaginings, then we do not falsely believe while dreaming that we are now awake, but only imagine that we do (Sosa 2007). It is not clear though that this protects us from deception. If dream beliefs fall short of real beliefs, this might even make the specter of dream deception more worrisome: in mistaking dream beliefs for the real thing, we would now be deceived about the status of our own mental states (Ichikawa 2008).

It is also not clear whether the same type of argument extends to mental states other than beliefs. As Lewis points out, a person might

in fact believe or realize in the course of a dream that he was dreaming, and even if we said that, in such case, he only dreamt that he was dreaming, this still leaves it possible for someone who is asleep to entertain at the time the thought that he is asleep. (Lewis 1969: 133)

Mental states other than believing such as entertaining, thinking, or minimally appraisive instances of taking for granted might be sufficient for deception (Reed 1979).

The debate about dream beliefs is paralleled by a debate about whether delusions are beliefs or imaginings (see Currie 2000; Currie & Ravenscroft 2002; McGinn 2004; Bayne & Pacherie 2005; Bortolotti 2009; Gendler 2013). Both debates might plausibly inform each other, especially as dreams are sometimes proposed to be delusional (Hobson 1999).

3. Dreaming and theories of consciousness

Dreams are a global state of consciousness in which experience arises under altered behavioral and neurophysiological conditions as compared to standard wakefulness; unlike other altered states of consciousness (such as drug-induced or deep meditative states) and pathological wake states (such as psychosis or neurological syndromes), dreams occur spontaneously and regularly in healthy subjects. For both reasons, many regard dreams as a test case for theories of consciousness or even an ideal model system for consciousness research (Churchland 1988; Revonsuo 2006).

Existing proposals differ on the phenomenology of dreaming: referring to dream bizarreness, Churchland describes dream experience as robustly different from waking, whereas Revonsuo argues dreaming is similar to waking and the purest form of experience:

the dreaming brain brings out the phenomenal level of organization in a clear and distinct form. Dreaming is phenomenality pure and simple, untouched by external physical stimulation or behavioural activity. (Revonsuo 2006: 75)

Revonsuo argues dreaming reveals the basic, state-independent structure of consciousness to be immersive: “dreaming depicts consciousness first and foremost as a subjective world- for-me ” (Revonsuo 2006: 75). This leads him to introduce the “world-simulation metaphor of consciousness”, according to which consciousness itself is essentially simulational and dreamlike. This is taken to support internalism about conscious experience.

This latter claim is also contentious. Noë (2004: 213) argues that phenomenological differences between dreaming and waking (such as greater instability of visual dream imagery) result from the lack of dynamic interaction with the environment in dreams. He proposes this shows that neural states are sufficient for dreaming but denies they are also sufficient for perceptual experience.

A possible problem for both views is their reliance on background assumptions about the phenomenology of dreaming and its disconnection from environmental stimuli and bodily sensations. Windt (2015a, 2018) argues both internalism and externalism mistakenly assume dreams to be isolated from external sensory input and own-body perception; she believes both the phenomenology of dreaming and its correlation with external stimuli are complex and variable. She argues the analysis of dreaming does not clearly support either side in the debate on internalism vs externalism (but see Rosen 2018a). Generally, in the absence of a well worked out theory of dreaming and its sleep-stage and neural correlates, proposals for using dreaming as a model system or test case run the risk of relying on an oversimplified description of the target phenomenon (Windt & Noreika 2011).

Recent accounts appealing to generative models and predictive processing (Clark 2013b; Hohwy 2013) suggest a new, unified account of perception, imagination, and dreaming. In these accounts, different mental states, including perception and action, embody different strategies of hypothesis testing and prediction error minimization. Perception is the attempt to model the hidden external causes of sensory stimuli; action involves keeping the internal model stable while changing the sensory input. Clark argues that on such a model,

systems that know how to perceive an object as a cat are thus systems that, ipso facto , are able to use a top-down cascade to bring about the kinds of activity pattern that would be characteristic of the presence of a cat. […] Perceivers like us, if this is correct, are inevitably potential dreamers and imaginers too. Moreover, they are beings who, in dreaming and imagining, are deploying many of the very same strategies and resources used in ordinary perception. (Clark 2013a: 764)

Predictive processing accounts have also been used to explain specific features of dreaming. Bizarreness has been associated with the comparative lack of external stimulus processing, implying dream imagery is relatively unconstrained by prediction errors (cf. Hobson & Friston 2012; Fletcher & Frith 2008; Bucci & Grasso 2017). Windt (2018) suggests a predictive processing account of dream imagery generation that links bodily self-experience to own-body perception and subtle motor behaviors such as twitching in REM sleep (Blumberg 2010; Blumberg & Plumeau 2016). She argues that movement sensations in dreams, in relation to REM-sleep related muscle twitching, involve a form of bodily self-sampling in which coordinated muscular activity contributes to the generation and maintenance of a body model. This is important because in predictive processing accounts neither the bodily nor the external causes of sensory inputs are known; at the same time, having an accurate body model is a prerequisite for action, requiring the system to disambiguate between self- and other generated changes to sensory inputs. Especially in early development, sleep might provide the ideal conditions for exploring one’s own body via subtle but coordinated muscular activity while processing of visual and auditory stimuli is reduced.

Dreams have also been suggested as a test case for whether phenomenal consciousness can be divorced from cognitive access (e.g., Block 2007; but see Cohen & Dennett 2011). Sebastián (2014a) argues that dreams provide empirical evidence that conscious experience can occur independently of cognitive access. This is because during (non-lucid) REM-sleep dreams, the dorsolateral prefrontal cortex (dlPFC) as the most plausible mechanism underlying cognitive access is selectively deactivated (see also Pantani et al. 2018). This would challenge theories linking conscious experience to access, such as higher-order-thought theory (Sebastián 2014b). However, both the hypoactivation of the dlPCF in REM sleep and its association with cognitive access have been debated. Fazekas and Nemeth (2018) suggest that certain kinds of cognitive access may be independent of dlPFC activation, necessitating a more complex account.

Dreaming has been suggested as a model system not just of waking consciousness in general, but also of psychotic wake states in particular. The analogy between dreaming and madness has a long philosophical history (Plato, Phaedrus ; Kant 1766; Schopenhauer 1847) and finds particularly stark expression in Hobson’s claim that “dreaming is not a model of a psychosis. It is a psychosis. It’s just a healthy one” (Hobson 1999: 44). Gottesmann (2006) proposes dreaming as a neurophysiological model of schizophrenia. There is a rich discussion on the theoretical and methodological implications of dream research for psychiatry (see Scarone et al. 2007; d’Agostino et al. 2013; see Windt & Noreika 2011 as well as the other papers in this special issue) and a number of studies have investigated differences in dream reports from schizophrenic and healthy subjects (Limosani et al. 2011a,b).

Rather than likening dreaming to waking in general or specific wake states such as psychosis, there have also been attempts to compare specific dream phenomena to wake-state delusions. Gerrans (2012, 2013, 2014) focuses on character misidentification in dreams and delusions of hyperfamiliarity (such as the Frégoli delusion, in which strangers are mistakenly identified as family members, and déjà vu ) to argue that anomalous experience and faulty reality testing both play a role in delusion formation. Rosen (2015) analyzes instances of thought insertion and of auditory hallucinations, which are key symptoms of schizophrenia, to raise broader questions about the altered sense of agency in dreams as compared to waking.

Philosophers have focused almost exclusively on dreaming, largely leaving to the side questions about dreamless sleep including whether it is uniformly unconscious. In recent years there has been a surge of interest in the possibility of dreamless sleep experience and foundational issues about the definition of sleep and waking. This has been paralleled by growing interest in dreaming in NREM sleep.

Conceptually, interest in dreamless sleep experience has been facilitated by the precise definition of dreaming offered by simulation views (Revonsuo et al. 2015). If dreams are immersive sleep experiences characterized by their here -and- now structure, it makes sense to ask whether this is true for all or just a subset of sleep-related experiences and whether non-immersive sleep experiences exist. By contrast, if dreaming is broadly identified with any conscious mentation in sleep (Pagel et al. 2001), there is no conceptual space for dreamless sleep experience.

Following Thompson's (2014, 2015) discussion of dreamless sleep in Indian and Buddhist philosophy, Windt and colleagues (2016; see also Windt 2015b) introduce a framework for different kinds of dreamless sleep experience ranging from thinking and isolated imagery, perception, or bodily sensations, where these lack integration into a scene, to minimal kinds of experience lacking imagery or specific thought contents. A possible example of minimal phenomenal experience in sleep are white dreams, where people report having had experiences during sleep but cannot remember any details. Taken at face value, some white dream reports might describe experiences that lack reportable content (Windt 2015b); others might describe forgotten dreams or dreams with degraded content (Fazekas et al. 2018). Another example are reports of witnessing dreamless sleep, as described in certain meditation practices. This state is said to involve non-conceptual awareness of sleep, again in the absence of imagery or specific thought contents, and loss of sense of self (Thompson 2014, 2015). Some schools in Buddhist philosophy explain claims of deep and dreamless sleep by saying we never fully lose consciousness in sleep (Prasad 2000, 66; and Thompson 2014, 2015).

Empirically, interest in dreamless sleep experience is paralleled by increasing interest in experiences in NREM sleep (Fazekas et al. 2018). Most researchers now accept that dreaming is not confined to REM sleep, but also occurs at sleep onset and in NREM sleep. The deeper stages of NREM sleep are particularly interesting as they involve roughly similar proportions of dreaming, unconscious sleep, and white dreams (Noreika et al. 2009: Siclari et al. 2013, 2017). In the search for the neural correlates of dreaming vs unconscious dreamless sleep, this makes comparisons within the same sleep stage possible and avoids confounds involved in comparing presumably dreamful REM sleep with presumably dreamless NREM sleep. Findings suggest that activity in the same parietal hot zone underlies dreaming in both NREM and REM sleep (Siclari et al. 2017).

Where sleep and dream research have traditionally tried to identify the sleep stage correlates of dreaming, newer research suggests local changes occurring independently of sleep stages might in fact be more relevant. Traditionally regarded as global, whole-brain phenomena, there is now increasing evidence that sleep itself is locally driven, and local changes in sleep depth might be associated with changes in sleep-related experience (Siclari & Tononi 2017; Andrillon et al. 2019). While sleep and dream research are often considered as separate fields, changes in how sleep in general and sleep stages in particular are defined appear closely associated with changes in the theoretical conception of dreaming and its empirical investigation.

Historically, discoveries about dreaming have precipitated changing conceptions of sleep (for an excellent history of the study of sleep and dreaming, see Kroker 2007). Following Aristotle ( On Sleeping and Waking ), sleep was traditionally defined in negative terms as the absence of wakefulness and perception. This is still reflected in Malcolm’s assumption that “to a person who is sound asleep, ‘dead to the world’, things cannot even seem” (Malcolm 1956: 26). With the discovery of REM sleep, sleep came to be regarded as a heterogeneous phenomenon characterized by the cyclic alteration of different sleep stages. REM sleep was now considered as “neither sleeping nor waking. It was obviously a third state of the brain, as different from sleep as sleep is from wakefulness” (Jouvet 1999: 5). The folk-psychological dichotomy between sleep and wakefulness now seemed oversimplified and empirically implausible. At the same time dreaming, which had previously been considered as an intermediate state of half-sleeping and half-waking, came to be regarded as a genuine sleep phenomenon, but narrowed to REM sleep. Today, the framework for describing dreams and other sleep-related experiences is more precise, but dreaming has also been cast adrift from REM sleep.

A closely associated issue is how to define waking. Crowther’s (2018) capacitation thesis casts waking consciousness as a state in which the individual is fully switched on to their environment, but also to their own epistemic (cf. O’Shaugnessy 2002) and agentive potential; the waking individual is empowered to act and think in certain ways, though this potential need not be actualized. By contrast, dreaming is an “imagining-of consciousness” (O’Shaughnessy 2002: 430) and consciousness is conceptually tied to wakefulness. Because in lucid dreams, the epistemic and agentive profile of waking is at least partly realized, they might, according to Crowther, be regarded as closer to waking than nonlucid dreams.

This account of waking and sleep may also have consequences for the imagination model of dreaming and dream skepticism (Soteriou 2017). As in the imagination model, dreaming would be passive and action, including cognitive agency, would be tied to waking. If dreaming nonetheless involved passive episodes of imagining oneself to be active, one would be unable to tell that one were dreaming and imagining, as this insight would require the exercise of real agency. The sceptical consequence would be that when dreaming, one would lose agency as well as the capacity to gain insight into one’s current state. Yet our ability to know we are waking when waking would be unscathed; according to Soteriou, waking would thus have an epistemic function connected to the capacity to exercise agency over our mental lives.

Finally, definitions of consciousness themselves are bound up with conceptions of sleep and dreaming. As dreaming went from a state whose experiential status was doubted to being widely recognized as a second global state of consciousness, consciousness sometimes came to be defined contrastively as that which disappears in deep, dreamless sleep and reappears in waking and dreaming (Searle 2000; Tononi 2008). In light of dreamless sleep experience, such definitions are problematic (Thompson 2014, 2015; Windt 2015b; Windt et al. 2016). Dreamless sleep experience has been proposed to be particularly relevant for understanding minimal phenomenal experience, or the conditions under which the simplest kind of conscious experience arises (Windt 2015b). The investigation of dreamless sleep might thus shed light on the transition from unconscious sleep to sleep-related experience.

We almost always have a self in dreams, though this self can sometimes be a slightly different (e.g. older or younger) version of our waking self or even a different person entirely. Dreams therefore raise interesting questions about the identity between the dream and waking self. Locke (1689) invites us to imagine two men alternating in turns between sleep and wakefulness and sharing one continuously thinking soul (Locke 1689: II.I.12). He argues that if one man retained no memory of the soul’s thoughts and perceptions while it was linked to the other man’s body, they would be distinct persons. His position is that personal identity depends on psychological continuity, including recall: in the absence of recall, as illustrated by the toy example of two people sharing one soul, continuous conscious thinking does not suffice for identity. Locke also rejects the possibility of unrecalled dreams and the idea that we dream throughout sleep, remembering only a small proportion of our dreams (Locke 1689: II.I.19).

Valberg distinguishes between the subject of the dream (i.e., the dream self) and the sleeping person who is the dreamer of the dream and recalls it upon awakening (Valberg 2007). He argues that awakening from a dream involves crossing a chasm between discrete worlds with discrete spaces and times; it does not make sense to say that “the ‘I’ at these times [is] a single individual who crosses from one world to the other” (Valberg 2007: 69). According to Valberg, this is relevant to dream skepticism because there is no simple way to make sense of the claims that it is I who emerge from a dream or that I was the victim of dream deception.

Vicarious dreams, or dreams in which the protagonist of the dream seems to be a different person from the dreamer, are particularly puzzling with respect to identity. They may even raise the question of whether the dream self has an independent existence (Rosen & Sutton 2013: 1047). Such dreams are superficially similar to cases in which we imagine being another person, but according to Rosen and Sutton require a different explanation: in the case of dreaming, the imagined person’s thoughts are not framed as diverging from one’s own and one does not retain one’s own perspective in addition to the imagined one; in nonlucid dreams, only the perspective of the dream’s protagonist is retained.

The dream self is also at the center of simulation views of dreaming, which define dreaming via its immersive, here and now character as the experience of a self in a world. This leads to further questions about the phenomenology of self-experience in dreams and how it is different from waking self-experience. Different versions of the simulation view focus on different aspects of self- and world experience in dreams, ranging from social simulation (Revonsuo et al. 2015) to the typical features of selfhood in dreams (Revonsuo 2005, 2006, Metzinger 2003, 2009) to the minimal conditions for experiencing oneself as a self in dreams and what this tells us about minimal phenomenal selfhood in general (Windt 2015a, 2018). Yet these different versions of the simulation view are largely complementary and together have forged unity in a field that was previously hampered by lack of agreement about the definition of dreaming. They also integrate the philosophy of dreaming and scientific dream research.

As so often in debates about dreaming, there is disagreement about basic phenomenological questions. Revonsuo (2005) describes self-experience including bodily experience in dreams as identical to waking, whereas Metzinger (2003, 2009; see also Windt & Metzinger 2007) argues that important layers of waking self-experience (such as autobiographical memory, agency, a stable first-person perspective, metacognitive insight, and self-knowledge) are missing in nonlucid dreams. He argues this is due to the cognitive and mnemonic deficit that characterizes nonlucid dreams (cf. Hobson et al. 2000). Windt (2015a) analyzes the range of cognitive and bodily self-experience in dreams, both of which she describes as variable. She argues that in a majority of cases, dreams are weakly phenomenally embodied states in which bodily experience is largely related to movement sensations but a detailed and integrated body representation is lacking; instead, bodily experience in dreams is largely indeterminate (for an attempt to test this empirically, see Koppehele-Gossel et al. 2016). She proposes this is because dreams are also weakly functionally embodied states, in which the specific pattern of bodily experience reflects altered processing of bodily sensations (as in the illusion view). She also analyzes instances of bodiless dreams, in which dreamers say they experienced themselves as disembodied entities, to argue that self-experience can be reduced to pure spatiotemporal-self-location (Windt 2010); she proposes these cases can help identify the conditions for the emergence of minimal phenomenal selfhood (Blanke & Metzinger 2009; see also Metzinger 2013b).

How the phenomenology of dreaming compares to waking and what to say about how the dream self relates to the waking self bears on questions about the moral status of dreams. For Augustine ( Confessions ) dreams were a cause of moral concern because of their indistinguishability from waking life. What particularly worried him about dreams of sexual acts was their vividness, as well as the feeling of pleasure and seeming acquiescence or consent on the part of the dreamer. He concluded, however, that the transition from sleep to wakefulness involves a radical chasm, enabling the dreamer to awaken with a clear conscience and absolving them from taking responsibility for their dream actions.

What exactly Augustine thought the chasm between dreaming and waking consists in allows for different interpretations (Matthews 1981). Firstly, if the dream and waking self are not identical, then waking Augustine is not morally responsible for dream-Augustine’s actions. Secondly, actions performed in dreams might be morally irrelevant because they did not really happen. And thirdly, assuming that moral responsibility requires the ability to act otherwise, dreams provide no grounds for moral concern because we cannot refrain from having certain types of dreams.

The issue of dream immorality may also present a choice point between different accounts of moral evaluation. Where internalists assume the moral status of a person’s actions is entirely determined by internal factors such as intentions and motives, externalists look beyond these to the effects of actions. Driver (2007) argues that the absurdity of dream immorality itself should count against purely internalist accounts; yet she also acknowledges this absurdity is not a necessary feature of dreams.

Central to the question of dream immorality is the status of dreams as actions rather than mere behaviors. Mullane (1965) argues that while we don’t have full control over our dreams, they are not completely involuntary either; as is the case for blushing, considerable effort is required to attain control over our dreams and in some cases they can even be considered as actions. That lucid dream control is, to some extent, a learnable skill (Stumbrys et al. 2014) lends some support to this claim.

6. The meaning of dreams and the functions of dreaming

Philosophical discussions of dreaming tend to focus on (a) dream deception and (b) questions about the ontology of dreaming, its moral status, etc., that tend to intersect with dream skepticism. By contrast, the main source of interest in dreams outside of philosophy traditionally has been dream interpretation and whether dreams are a source of knowledge and insight. Historically, the epistemic status of dreams and the use of prophetic and diagnostic dreams was not just a theoretical, but a practical problem (Barbera 2008). Different types of dreams were distinguished by their putative epistemic value. Artemidorus, for instance, used the term enhypnion to refer to dreams that merely reflect the sleeper’s current bodily or psychological state and hence do not merit further interpretation, whereas he reserved the term oneiron for meaningful and symbolic dreams of divine origin.

The practice of dream interpretation was famously attacked by Aristotle in On Prophecy in Sleep . He denied that dreams are of divine origin, but allowed that occasionally, small affections of the sensory organs as might stem from distant events that cannot be perceived in waking are perceptible in the quiet of sleep. He also believed such dreams were mostly likely to occur in dullards whose minds resemble an empty desert – an assessment that was not apt to encourage interest in dreams (Kroker 2007: 37). A similarly negative view was held by early modern philosophers who believed dreams were often the source of superstitious beliefs (Hobbes 1651; Kant 1766; Schopenhauer 1847).

In Freudian dream theory, dream interpretation once more assumed a prominent role as the royal road to knowledge of the unconscious. This was associated with claims about the psychic sources of dreaming. Freud (1899) also rejected the influence of external or bodily sources, as championed by contemporary proponents of somatic-stimulus theory.

In the neuroscience of dreaming, Hobson famously argued that dreams are the product of the random, brain-stem driven activation of the brain during sleep (Hobson 1988) and at best enable personal insights in the same way as a Rorschach test (Hobson et al. 2000). Dennett (1991) illustrates the lack of design underlying the production of dream narratives through the “party game of psychoanalysis”, which involves an aimless game of question-and-answer. In the game, players follow simple rules to jointly produce narratives that can seem symbolic and meaningful, even though no intelligent and deliberate process of narration was involved.

Even if we grant that dreams are not messages from a hidden entity in need of decoding, this does not imply that dream interpretation cannot be a personally meaningful source of insight and creativity (Hobson & Wohl 2005). Whether and under which conditions, and following which methods, dream interpretation can lead to personally significant insights is an empirical question that is only beginning to be investigated systematically (see Edwards et al. 2013).

Finally, throughout history, views on the epistemic status of dreams and the type of knowledge to be gained from dream interpretation (e.g., knowledge about the future, diagnosis of physical illness, or insights about one’s current concerns) often changed in tandem with views on the origin and sources of dreaming, which gradually moved from divine origins and external sources, via the body, to the unconscious, and finally to the brain.

Different theories on the functions of dreaming have been proposed and the debate is ongoing. An important distinction is between the functions of sleep stages and the functions of dreaming. Well-documented functions of REM sleep include thermoregulation and the development of cortical structures in birds and mammals, as well as neurotransmitter repletion, the reconstruction and maintenance of little-used brain circuits, the structural development of the brain in early developmental phases, as well as the preparation of a repertoire of reflexive or instinctive behaviors (Hobson 2009). Yet none of these functions are obviously linked to dreaming. An exception is protoconsciousness theory, in which REM sleep plays an important role in foetal development by providing a virtual world model even before the emergence of full-blown consciousness (Hobson 2009: 808) .

Numerous studies have investigated the contribution of sleep to memory consolidation, with different sleep stages promoting different types of memories (Diekelmann et al. 2009; Walker 2009). However, only a few studies have investigated the relationship between dream content and memory consolidation in sleep (for a review, see Nielsen & Stenstrom 2005). Dreams rarely involve episodic replay of waking memories (Fosse et al. 2003). The incorporation of memory sources seems to follow a specific temporal pattern in which recent memories are integrated with older but semantically related memories (Blagrove et al. 2011). Nielsen (2017) presents a model of how external and bodily stimuli on one hand and short- and long-term memories on the other hand form seemingly novel, complex, and dreamlike images at sleep onset; he proposes these microdreams shed light on the formation and sources of more complex dreams. There is also some evidence that dream imagery might be associated with memory consolidation and task performance after sleep, though this is preliminary (Wamsley & Stickgold 2009, 2010; Wamsley et al. 2010).

Prominent theories on the function of dreaming focus on bad dreams and nightmares. It has long been thought that dreaming contributes to emotional processing and that this is particularly obvious in the dreams of nightmare sufferers or in dreams following traumatic experiences (e.g., Hartmann 1998; Nielsen & Lara-Carrasco 2007; Levin & Nielsen 2009; Cartwright 2010; Perogamvros et al. 2013). Based on the high prevalence of negative emotions and threatening dream content, threat simulation theory suggests that the evolutionary function of dreaming lies in the simulation of ancestral threats and the rehearsal of threatening events and avoidance skills in dreams has an adaptive value by enhancing the individual’s chances of survival (see Revonsuo 2000; Valli 2008). A more recent proposal is social simulation theory, in which social imagery in dreams supports social cognition, bonds, and social skills. (Revonsuo et al. 2015).

An evolutionary perspective can also be fruitfully applied to specific aspects of dream phenomenology. According to the vigilance hypothesis , natural selection disfavored the occurrence of those types of sensations during sleep that would compromise vigilance (Symons 1993). Dream sounds, but also smells or pains might distract attention from the potentially dangerous surroundings of the sleeping subject, and the vigilance hypothesis predicts that they only rarely occur in dreams without causing awakening. By contrast, because most mammals sleep with their eyes closed and in an immobile position, vivid visual and movement hallucinations during sleep would not comprise vigilance and thus can occur in dreams without endangering the sleeping subject. Focusing on the stuff dreams are not made of might then be at least as important for understanding the function of dreaming as developing a positive account.

Finally, even if dreaming in general and specific types of dream content in particular were found to be strongly associated with specific cognitive functions, it would still be possible that dreams are mere epiphenomena of brain activity during sleep (Flanagan 1995, 2000). It is also possible that the function of dreams is not knowable (Springett 2019).

A particular problem for any theory on the function of dreaming is to explain why a majority of dreams are forgotten and how dreams can fulfill their putative function independently of recall. Crick and Mitchinson (1983) famously proposed that REM sleep “erases” or deletes surplus information and unnecessary memories, which would suggest that enhanced dream recall is counterproductive. Another problem is that dreaming can be lost selectively and independently of other cognitive deficits (Solms 1997, 2000).

Some of the problems that arise for theories on the functions of dreaming can be avoided if we do not assume that dreaming has a specific function, separate from the function(s) of conscious wakeful states. This depends on the broader taxonomy of dreaming in relation to wakeful states. For example, if dreaming is continuous with waking mind wandering, imagination, and/or own-body perception, we should not expect it to have a unique function, but rather to express a similar function as these wakeful states, perhaps to varying degrees. Nor should we expect dreams to have a single function; the functions of dreaming might be as varied and complex as those of consciousness, and given the complexity of the target phenomenon, the failure to pin down a single function should not be surprising (Windt 2015a).

Questions about dreaming in different areas of philosophy such as epistemology, ontology, philosophy of mind and cognitive science, and ethics are closely intertwined. Scientific evidence from sleep and dream research can meaningfully inform the philosophical discussion and has often done so in the past. The discussion of dreaming has also often functioned as a lens on broader questions about knowledge, morality, consciousness, and self. Long a marginalized area, the philosophy of dreaming and of sleep is central to important philosophical questions and increasingly plays an important role in interdisciplinary consciousness research, for example in the search for the neural correlates of conscious states, in conscious state taxonomies, and in research on the minimal conditions for phenomenal selfhood and conscious experience.

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How to cite this entry . Preview the PDF version of this entry at the Friends of the SEP Society . Look up topics and thinkers related to this entry at the Internet Philosophy Ontology Project (InPhO). Enhanced bibliography for this entry at PhilPapers , with links to its database.

• Philosophy of Dreaming , entry in the Internet Encyclopedia of Philosophy .
• Dreams , PhilPapers collection.
• Dreams and Skepticism , PhilPapers collection.

belief | Berkeley, George | delusion | Descartes, René: epistemology | imagination | Locke, John | perception: the problem of | personal identity | personal identity: and ethics | Plato: on knowledge in the Theaetetus | sense data | skepticism | skepticism: and content externalism

Acknowledgments

I want to thank Regina Fabry and two anonymous reviewers for helpful comments and constructive criticism on an earlier version of this manuscript. And as always, I am greatly indebted to Stefan Pitz for his support.

Copyright © 2019 by Jennifer M. Windt < jennifer . windt @ monash . edu >

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Understanding Dreams

Reviewed by Psychology Today Staff

Dreams are imaginary sequences—some with clear narratives, and some without—that play out in people’s minds as they sleep. Most dreams consist of a series of images, sensations, and emotions, and range from pleasant and exciting to boring or even terrifying.

Dreams have long captured the imagination of humankind; early in recorded history, they were thought to be messages from deities or a means to predict the future. In more recent years, they have drawn the focus of psychologists, neurologists, philosophers, and biologists, all of whom continue to study dreams, what they mean, and why dreaming is necessary for humans and animals alike.

On This Page

• What We Know About Dreaming
• Understanding Common Dreams

Despite the fact that everyone is thought to dream, there remains much that we don’t understand about how dreaming occurs, how long it lasts, and the exact purpose—or purposes—that it serves. What is known, however, is that dreams appear primarily in the Rapid Eye Movement (REM) stage of sleep and are typically accompanied by high levels of brain activity and some physical movement (particularly in the eyes). Even people who never recall dreaming are thought to dream at least occasionally, but the fact that they take place during sleep means that researchers have difficulty confirming whether or not dreams actually occur.

Many researchers believe that dreaming has a purpose , but what exactly that purpose is remains an open question. Some believe it helps the brain consolidate memories and may aid learning; others believe it allows the brain to simulate threats to better protect itself in the future. More philosophical and psychodynamic theories suggest that dreams help us process difficult thoughts, emotions, and experiences in order to boost psychological well-being upon waking.

Forgetting dreams is far from uncommon. Many (if not most) dreams are forgotten, either immediately after waking or later on. Some researchers refer to immediately-forgotten dreams as “white dreams” ; some evidence suggests that as many as one-third of awakenings are associated with white dreams, and may be due to the fact that the brain does not encode memories the same way while dreaming as it does while awake.

Someone who wants to remember their dreams more often can take certain steps to do so, such as keeping a journal by their bed so they can record details from their dreams immediately upon waking.

The National Sleep Foundation estimates that in a typical 8-hour night, approximately 2 hours (at least) is spent dreaming. While dreaming is theorized to be most prevalent during REM sleep (which comprises approximately 20 percent of overall sleep time), some evidence suggests that dreaming can occur to some extent in other stages of sleep as well; if such findings are supported further, they may indicate that people dream all (or most) of the time .

Estimates range from a few seconds to up to 45 minutes; since people typically have several dreams in an evening, it’s highly likely that the length of individual dreams varies over the course of a night. Researchers have no exact way to measure how long dreams last , but they are able to estimate based on sleep stages, dream recall, and physical signs. Early in the night, dreams are thought to be shorter; the longest dreams are theorized to occur right before waking.

Yes; in fact, it’s likely more common than not. As their body and brain cycle through the different sleep stages, people typically go in and out of several different dreams. The dreams that occur right after someone drifts off are typically the shortest; dreams tend to get longer as the night progresses and the individual spends longer amounts of time in each sleep phase.

The phrase “lucid dreaming” refers to dreams in which the person recognizes that they are dreaming and feels as if they can take control of what happens in the dream. Most people are thought to experience lucid dreaming at least once in their lifetime; a smaller percentage report doing so regularly. Some evidence suggests that specific strategies such as self-suggestion (the dreamer saying to himself that he will have a lucid dream before falling asleep) may increase the odds of an individual triggering a lucid dream .

Many dreams are entirely unique. But some dream themes may be universal; indeed, multiple studies have found that people from different locations, cultures, and ethnic groups report several common dream themes. Certain dream themes may be indicative of stress or preoccupation with a particular person or event, but most experts agree that dreams don’t necessarily “mean” anything or indicate the individual’s true nature. Many people are occasionally alarmed by the content of their dreams. But it may give them comfort to know that the vast majority of people have had unpleasant or embarrassing dreams and that such dreams do not indicate any abnormality.

Some of the most common dream themes include being chased, falling, going to school, or engaging in sexual activity. Other research indicates that dreams about flying , trying to do the same thing over and over again, or spending time with someone who is dead in real life may also be common around the globe.

Whether dreams really mean anything—or whether they’re just random images cobbled together by the brain—has been debated by psychologists and neuroscientists for many years. Freud, for instance, theorized that dreams give insight into the unconscious mind and provide clues to one’s deeper self; though many modern researchers disagree with his theories, some continue to speculate that dream imagery is relevant to our day-to-day emotional states and may signal that certain thoughts are preoccupying us. Some neurologists, on the other hand, theorize that dreams are just a side effect of memory consolidation and other brain-based processes, with little to no meaning beyond that. Many lay people, however, instinctively feel as if their dreams are trying to tell them something, and the question remains up for debate in many corners of the scientific community.

Someone who is deeply stressed about work or a personal situation may very well find the same scenario popping up in their dreams. It’s no surprise, then, that some researchers believe that one potential purpose of dreams is to help the brain process stress and other difficult emotions. Stress dreams typically focus on the more mundane aspects of daily life—an upcoming deadline, for instance—but people who live through traumatic events or natural disasters (like earthquakes or the COVID-19 pandemic) also report repetitive stress dreams centering on the event.

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What, to the Writer, Are Dreams?

Lauren acampora on the mythic links between dream life and creativity.

“Dream is the personalized myth, myth the depersonalized dream.” –Joseph Campbell

One morning, when I was younger, I gave a detailed description of my previous night’s dream to my mother. When I finished, she said, “I’m going to tell you something. Don’t ever share your dreams with anyone except your spouse. It’s boring to listen to other people’s dreams.”

I was offended at first. How could anyone, not to mention my own mother, fail to find my dreams as fascinating as I did? But of course she was right; it’s almost always deadly to hear other people talk about their dreams. As a rule, dreams die in the glare of the waking world, their shimmering aura evaporating in the harsh air outside the psyche. And yet, paradoxically, it’s the emotional aura of dreams that makes them feel so urgently worth sharing in the first place.

Needless to say, I didn’t listen to my mother. That is, I still share my dreams promiscuously—just not verbally.

Like so many other writers and artists, I employ dreams in my creative work. They’re an engine, a lending library. It’s a thrill to awake with a strange, arresting image in mind, or still grasping the thread of an allegorical dream story. Sometimes, a vision or scenario arrives as a package deal: the story is encased within the vision, packed up tight with a certain mood. For me, entire short stories have sprung from such vision: a woman alone in a pool, a finger touching a brain, a blindfolded child. A haunting dream of orange curtains in a hotel room has rolled into an entire novel (in which orange hotel curtains do not ever appear). And the power and mystery of dreams themselves inspired my novel The Paper Wasp , in which the narrator illustrates—and ultimately enters—her vivid, seemingly premonitory dreams.

There’s no shortage of literature and art that we know to have sprung from dreams. As legend has it, the poet Samuel Taylor Coleridge transcribed the first lines of “Kubla Khan” from a dream; the idea for Frankenstein came to Mary Shelley in her sleep; Robert Louis Stevenson conceived of Dr. Jekyll and Mr. Hyde in a consumptive fever dream; Stephen King came up with the idea for Misery while napping on a plane ; William Styron had a dream that inspired Sophie’s Choice . One of the most prolific dream miners of all was Edgar Allen Poe, who used his frequent nightmares in much of his work. And famously, Paul McCartney dreamed the tune for the song “Yesterday.” Upon waking, he asked his friends if they knew it. “It’s a good little tune,” he said, “but I couldn’t have written it because I dreamt it.”

Dreams can feel like messages from another place, so it’s no surprise that many ancient cultures believed dreams to be transmissions of divine knowledge. The Ancient Egyptians considered dreams to be oracular and held vivid dreamers in high regard. They practiced dream incubation and lucid dreaming, and employed dream guides called the “Masters of Secret Things” who lived in dream temples. The Greeks, too, incubated dreams, and thought that gods came to dreamers through a keyhole to deliver messages. The Aboriginal Australians and the Iroquois started their day by sharing dreams, which were considered a source of guidance for both the individual and the community. The Hindu religion, too, believes that in dreams one is given a glimpse of Vishnu, whose own dreaming mind creates our reality. It isn’t difficult to understand where such beliefs come from if you’ve ever dreamed of reading a book, sentence after lucid, elaborate sentence. “I couldn’t have written it,” you might think, “because I dreamt it.”

Brain science validates this phenomenon. Dreaming occurs during REM sleep, when the frontal lobe, the executive area of the brain, is shut down. Dreams are the mysterious activity of another part of the brain, beneath the scrutiny of the frontal lobe. Neurologically speaking, we really are receiving transmissions from a foreign entity; the unconscious, unobserved self slips through the keyhole when the guard is off duty.

Even during waking hours, the human brain is divided: the executive-desk frontal lobe and the inscrutable, intuitive limbic system are strangers to each other. In sleep, they are incommunicado. Because of this deep rift, the great majority of our dreams go unremembered, except on a buried emotional level. It’s difficult, even paradoxical, to try to bear total witness to them, akin to pinning down the present moment, halting the slippage of time. Just as the present can only be considered in retrospect, the unconscious mind can only be discerned via the remembered scraps of dreams. Any glimmers of awareness that may come during sleep, when a dream is fleetingly apprehended, are instances of the conscious half of the brain briefly observing and translating the activity of the submerged half: interpreting the enigmatic message of a stranger. These glimmers are rare and fleeting, occurring only during the hypnogogic and hypnopompic states, the liminal states between wakefulness and sleep.

In siphoning dreams for their work, writers and artists are tapping a valuable well. Dream logic and imagery carries an uncanny, allegorical quality that resonates deeply with readers and audiences. And it’s possible that dream recall actually enhances artistic output during waking hours. Scientific studies have confirmed a correlation between dream recall and creativity; those who recall dreams actually perform better on creativity evaluations. This may be because creative people are naturally better at recalling their dreams. It’s a chicken or egg situation: do creative people have more vivid and memorable dreams because they are innately creative, or can a brain become more creative through strengthening dream recall? Whatever the case, making use of dreams in art is a powerful way to reflect our foreign selves back to ourselves, while projecting that mystery self out to the world as archetypal image and story—dream as personalized myth, myth as depersonalized dream.

For writers, plugging into the unconscious provides a direct line to the human imagination in all its splendor and darkness. Indeed, in the midst of composing, it’s often unclear where the words are coming from. Sentences and imagery sometimes bubble up from a hidden well that surprises the conscious, transcribing mind. Some writers will tell you that they write in order to exorcise their demons, cleanse their psyches, to bring their fears and darkness into the light. Some will tell you that it’s better than therapy.

Writing at full tilt can be a euphoric state, tantamount to lucid dreaming. It’s half-awareness—one foot in, one foot out—a balance on the brink of consciousness. It’s not just in dreams that we can experience the ecstasy of flight and the exhilaration of omnipotence, but also when writing, when the words are flowing, the images appearing. Just as in a lucid dream, this exhilaration is paired with the knowledge that it can’t last, that it’s a temporary spell. Soon, we’ll become too aware of flying, and the spell will break and drop us to the ground. Still, we endeavor to capture and recapture this ecstasy of creative freedom, the ability to travel lightly anywhere at will, the bliss of floating to the treetops.

If writing fiction is analogous to dreaming, the experience of reading fiction can be, too. When we’re reading, another person is able to intrude into our psyches through the use of words alone, remotely projecting imagery onto the screens of our minds, suffusing them with atmosphere and mood. We are, in a way, sharing a dream with a stranger. And fiction, at its best, places a mirror before us, evoking terror and wonder. It affects us on an emotional level beyond language, and brings a frisson of recognition. There’s a momentary astonishment to encounter the familiar within the strange, something of our own inner lives on the page. There’s the eerie sense that the author has somehow entered and seen into us. The best art carries this sense of inevitability, of allegory, myth, dream—a truth that has always been there, that we already know in some deep part of ourselves.

This flare of astonishment is arguably the purpose of art. It’s the sudden thinning of the distance between us, the erosion of barriers that have been built and propped up by our conscious, waking lives. Like a flash of lightning, great art illuminates the human landscape in its breathtaking entirety and shows that the barriers are flimsy, false, only temporarily there. All at once, we are taken outside ourselves and given a glimpse of the Jungian collective unconscious, the subliminal wholeness of life, the enveloping dream of Vishnu. What is the purpose of all art, if not to puncture the illusion of fragmentation, to reveal the commonality of human experience, to return us—if briefly—to those collective waters?

__________________________________

The Paper Wasp   by Lauren Acampora is out now via Grove Atlantic.

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How to Interpret Dreams

Here are four main theories about what dreams might mean

Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

Amy Morin, LCSW, is a psychotherapist and international bestselling author. Her books, including "13 Things Mentally Strong People Don't Do," have been translated into more than 40 languages. Her TEDx talk,  "The Secret of Becoming Mentally Strong," is one of the most viewed talks of all time.

Verywell / Jessica Olah

• Freud's Unconscious Mind Theory
• Jung's Archetypes Theory
• Hall's Cognitive Process Theory
• Domhoff's Waking Life Theory

Popularizing Dream Interpretation

• The Effect of Biases

Dreams can be mysterious, exhilarating, or even terrifying, but understanding the meaning of our dreams can be downright baffling. While many theories exist to explain why we dream , no one yet fully understands their purpose, let alone how to interpret the meaning of dreams. However, psychologists have developed theories that might explain what dreams mean.

Here are four theories that can help you figure out what your dreams mean:

• Dreams as the Road to the Unconscious Mind : Developed by Sigmund Freud, this theory stated that dreams signified what people desire.
• Archetypes and the Collective Unconscious : Carl Jung also believed that dreams represented repressed wishes but also noted that dreams explored the underdeveloped parts of the mind.
• Dreams as a Cognitive Process : Calvin S. Hall theorized that what people do and think in their waking lives are what they see in their dreams.
• Dreams as a Reflection of Waking Life : G. William Domhoff, who worked with Hall, theorized a similar explanation for dreams.

Read ahead to learn more about each theory and how you can use them to interpret your dreams.

Freud: Dreams as the Road to the Unconscious Mind

In his book "The Interpretation of Dreams,"  Sigmund Freud suggested that the content of dreams is related to wish fulfillment.

Dream Are Our Wishes

Freud believed that the manifest content of a dream or the actual imagery and events served to disguise the latent content or the unconscious wishes of the dreamer. In other words, Freud believed that the content of your dreams shows what you desire in life.

Freud also described four elements of this process that he referred to as "dream work:"

• Condensation : Many different ideas and concepts are represented within a single dream. Information is condensed into a single thought or image.
• Displacement : This element of dream work disguises the latent content's emotional meaning by confusing the dream's important and insignificant parts.
• Symbolization : This operation also censors the repressed ideas in the dream by including objects meant to symbolize the latent content of the dream.
• Secondary revision : During this final stage of the dreaming process, Freud suggested that the bizarre elements of the dream are reorganized to make the dream comprehensible, thus generating the dream's manifest content.

Jung: Archetypes and the Collective Unconscious

While Carl Jung shared some commonalities with Freud, he felt that dreams were more than an expression of repressed wishes.

Dreams Explore the Underdeveloped Mind

Jung suggested that dreams revealed both the personal and collective unconscious and believed that dreams compensate for parts of the psyche that are underdeveloped in waking life.

Jung's Four Archetypes

Jung also suggested that archetypes such as the anima, the shadow, the animus, and the persona are often represented as symbolic objects or figures in dreams.

These symbols, he believed, represented attitudes that are repressed by the conscious mind .

Unlike Freud, who often suggested that specific symbols represent specific unconscious thoughts, Jung believed that dreams can be highly personal and that interpreting these dreams involved knowing a great deal about the individual dreamer.

Hall: Dreams as a Cognitive Process

Calvin S. Hall looked for themes and patterns by analyzing thousands of dream diaries from participants, eventually creating a quantitative coding system that divided what's in our dreams into several categories.

Dreams Contain Patterns Related to Waking Life

Hall proposed that dreams are part of a cognitive process in which dreams serve as "conceptions" of elements of our personal lives.

According to Hall’s theory, interpreting dreams requires knowing the following:

• The actions of the dreamer within the dream
• The objects and figures in the dream
• The interactions between the dreamer and the characters in the dream
• The dream’s setting, transitions, and outcome

The ultimate goal of this dream interpretation is not to understand the dream, however, but to understand the dreamer. Research by Hall revealed that the traits people exhibit while awake are the same as those expressed in dreams.

Domhoff: Dreams as a Reflection of Waking Life

G. William Domhoff is a prominent dream researcher who studied with Calvin Hall at the University of Miami.

Dreams Represent Daily Life

In large-scale studies on the content of dreams, Domhoff has found that dreams reflect the thoughts and concerns of a dreamer’s waking life.

Domhoff suggests a neurocognitive model of dreams in which the process of dreaming results from neurological processes and a system of schemas . Dream content, he suggests, results from these cognitive processes.

7 Theories on Why We Dream Simplified

Since the 1970s, dream interpretation has grown increasingly popular. Ann Faraday's 1974 book "The Dream Game" outlined techniques and ideas anyone can use to interpret their dreams.

Today, consumers can purchase various books that offer dream dictionaries, symbol guides, and tips for interpreting and understanding dreams.

How Biases Affect Dream Interpretation

Researchers Carey Morewedge and Michael Norton have studied the dreams of over 1,000 individuals from the United States, India, and South Korea.

They discovered that few college students who participated in the research believed that their dreams were simply the brain's response to random stimulation. Instead, most endorsed Freud's notion that dreams reveal unconscious wishes and urges.

What they also discovered, however, is that the weight and importance people attach to their dreams depends largely on their biases. People are more likely to remember negative dreams if they involve people they dislike. They are also more likely to take positive dreams seriously if they involve friends or loved ones.

In other words, people are motivated to interpret their dreams in ways that support their already existing beliefs about themselves, the world, and the people around them.

The researchers found that such things as the confirmation bias and the self-serving bias can impact how people respond to their dreams.

Because people tend to take their dreams seriously, the researchers suggest, they can also become a self-fulfilling prophecy . If you dream that you will fail an exam, you might be less motivated to study or even become so stressed out that you perform poorly.

Dreams may or may not have meaning, but the fact remains that interpreting dreams has become a popular pastime.

Schneider JA. From Freud's dream-work to Bion's work of dreaming: The changing conception of dreaming in psychoanalytic theory . Int J Psychoanal . 2010;91(3):521-40. doi:10.1111/j.1745-8315.2010.00263.x

Jung, CJ. Four Archetypes . Routledge; 2014.

Hall, CS. A cognitive theory of dreams . J Gen Psychol. 1953;49(2):273-282. doi:10.1080/00221309.1953.9710091

Domhoff, GW. A new neurocognitive theory of dreams . Dreaming . 2001;11(1):13-33. doi:10.1023/A:1009464416649

Morewedge CK, Norton MI. When dreaming is believing: The (motivated) interpretation of dreams . J Pers Soc Psychol . 2009;96(2):249-64. doi:10.1037/a0013264

Domhoff GW. Finding Meaning in Dreams: A Quantitative Approach . Springer Science and Business Media, 1996.

Domhoff GW. Toward a Neurocognitive Model of Dreams. In:  The Scientific Study of Dreams: Neural Networks, Cognitive Development, and Content Analysis . American Psychological Association, 2003.

Freud S. The Interpretation of Dreams . 1900.

Jung C. The Practical Use of Dream-analysis. In: The Practice of Psychotherapy: Essays on the Psychology of Transference . 1966.

By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

Essay on Dreams and Aspirations in Life

Students are often asked to write an essay on Dreams and Aspirations in Life in their schools and colleges. And if you’re also looking for the same, we have created 100-word, 250-word, and 500-word essays on the topic.

Let’s take a look…

100 Words Essay on Dreams and Aspirations in Life

Significance of dreams and aspirations.

Dreams and aspirations are vital in life. They give us a sense of purpose and direction. They motivate us to work hard, be persistent, and overcome obstacles.

Types of Dreams and Aspirations

Dreams and aspirations can be personal, like becoming a doctor, or collective, like working for world peace. They can be short-term or long-term, realistic or idealistic.

Realizing Dreams and Aspirations

To realize our dreams and aspirations, we need to plan, set goals, and take action. We also need patience and perseverance, as success may not come immediately.

In conclusion, dreams and aspirations are essential for a fulfilling life. They inspire us to strive for greatness and make a positive impact on the world.

250 Words Essay on Dreams and Aspirations in Life

Introduction.

Dreams and aspirations are the fulcrum of human existence, shaping our lives and paving the path towards success and fulfillment. They serve as a compass, guiding us through life’s labyrinth of opportunities and challenges.

The Power of Dreams

Dreams are not mere figments of our imagination but powerful catalysts for transformation. They propel us to transcend our limitations and foster a sense of purpose. The dream of a better life can instigate revolutions, as seen in the civil rights movements, while the dream of knowledge can lead to groundbreaking scientific discoveries.

Aspirations: The Fuel of Progress

Aspirations, on the other hand, are the tangible targets we set to achieve our dreams. They are the milestones that mark our journey towards our dreams. Aspirations keep us grounded and focused, preventing us from getting lost in the vast sea of dreams. They provide the motivation necessary to overcome obstacles and persist in the face of adversity.

The Interplay of Dreams and Aspirations

The interplay between dreams and aspirations is a dynamic and ongoing process. Dreams provide the vision, and aspirations provide the roadmap. They are interdependent and mutually reinforcing. Without dreams, aspirations lack direction, and without aspirations, dreams remain unfulfilled.

In conclusion, dreams and aspirations are the driving forces of life. They embody our hopes, desires, and ambitions, forming the blueprint of our life’s journey. Embracing them can lead to a life of fulfillment and satisfaction, a life that resonates with our deepest values and ideals.

500 Words Essay on Dreams and Aspirations in Life

The essence of dreams and aspirations.

Dreams and aspirations are the invisible forces that propel us forward on our life’s journey. They are the compass that guides us, the wind that fills our sails, and the beacon that illuminates our path. Dreams are not mere figments of our imagination; they are the blueprints of our future reality. Aspirations, on the other hand, are our desires for the attainment of something higher, something grander, something more profound.

Dreams are the seeds from which our future grows. They are the visions we create in our minds of what we want our life to be. Dreams give us a sense of purpose and direction. They are the catalysts that set us on our journey towards self-fulfillment and self-actualization. Dreams are not bound by the constraints of reality; they are the realm of the infinite, where anything is possible. They are the canvas on which we paint our future, the clay from which we mold our destiny.

Aspirations, however, are the fuel that powers our journey. They are our desires for achievement, our yearning for growth, our longing for self-improvement. Aspirations are the driving force behind our actions, the motivation that pushes us to strive for excellence, the hunger that compels us to reach for the stars. Aspirations are not just about wanting to achieve something; they are about the journey towards achievement, the process of growth and self-improvement.

Dreams and aspirations are interdependent and interconnected. Dreams give birth to aspirations, and aspirations breathe life into dreams. They are two sides of the same coin, two halves of the same whole. Dreams are the destination, and aspirations are the journey. Dreams are the vision, and aspirations are the action. Dreams are the blueprint, and aspirations are the construction.

The Role of Dreams and Aspirations in Life

Dreams and aspirations play a pivotal role in our lives. They shape our thoughts, influence our actions, and define our identity. They give our lives purpose and meaning, drive and direction. They inspire us to rise above our limitations, to transcend our boundaries, to defy the odds. They push us to explore, to innovate, to create. They challenge us to grow, to evolve, to become the best version of ourselves.

In conclusion, dreams and aspirations are the lifeblood of our existence. They are the essence of our being, the core of our identity. They are the wings that enable us to soar, the roots that ground us, the fire that ignites our spirit. Without dreams and aspirations, we are like a ship adrift at sea, a bird without wings, a flame without heat. With dreams and aspirations, we are unstoppable, unbreakable, invincible. They are not just a part of life; they are life itself.

That’s it! I hope the essay helped you.

If you’re looking for more, here are essays on other interesting topics:

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Home — Essay Samples — Life — Purpose — What Is My Biggest Dream

What is My Biggest Dream

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