Revisiting my Undergrad Days: A Defense of Descartes’ Dream Argument

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Part I.  Introduction

Global skepticism is the view that we cannot know if there is an external world or if there are other minds, whether we have souls or if God exists, or even whether we have free will. The global skeptic maintains a universal doubt about everything.  While the theory originated in ancient Greek philosophy with the Academic and Pyrrhonian skeptics, Descartes’s first meditation seems to bring us to ponder the position again and again.  His main questions while writing the Meditations are “How can we claim to know anything? And, if anything at all, what?”  His apprehension as to whether we can know anything at all arises from the fact that we base our supposed knowledge of the external world on what we receive from our senses.  However, our senses can be deceiving, and yet, we use these same senses to uncover what that deception may have been.  Nothing of which we cannot be certain can be considered knowledge, so while we can be reasonably certain at times of our senses, we cannot be absolutely certain because of their ability to deceive us.

With this in mind, Descartes presents a thought experiment, often referred to as The Dream Argument, which is meant to lead us to the skeptical position.  Critics of this argument claim that it is not strong enough to lead us to this skeptical position.  I will detail two of the most pressing objections given by these critics and show how each has failed in refuting that The Dream Argument is successful in leading to this skeptical position.  For the purposes of this paper, when talking about the ‘waking’ world, I will be referring to the reality in which I am writing this paper. Since the objections to Descartes’s argument I will be considering also make reference to being awake versus dreaming, I will allow them to have that distinction and consider these objections to have been made within the same reality in which I am writing this paper.



Part II.  The Dream Argument

Descartes writes:

“How often has it happened to me that in the night I dreamt that I found myself in this particular place, that I was dressed and seated near the fire, whilst in reality I was lying undressed in bed!… I have in sleep been deceived by similar illusions, and in dwelling carefully on this reflection I see so manifestly that there are no certain indications by which we may clearly distinguish wakefulness from sleep that I am lost in astonishment.  And my astonishment is such that it is almost capable of persuading me that I now dream.” -First Meditation.


From this, The Dream Argument can be summarized as follows:

  1.  We often have experiences of sensations and perceptions while we are dreaming that are exactly like the experiences we have of sensations when we are awake.
  2.  There is no qualitative difference between these experiences.


  1.  We are unable to differentiate these experiences, as they are occurring, as being those of dreaming or those of waking times, and it is then possible that the experiences each of us is having right now are within a dream.

This argument is meant to easily lead us to the skeptical position in that if each of us is now dreaming, then all of our beliefs about an external world, etcetera, are based on false perceptions.  If all our beliefs about an external world are based on false perceptions, then we can have no knowledge about an external world.  While on first glance the Dream Argument seems very successful in leading to this conclusion, there are still some critics that assert that this is not enough to defend skepticism.

Part III.  Objections and Responses

  1. The first objection I will explore has to do with premise two of the summarized argument above.  It states that there is no qualitative difference between the experiences we have while we are dreaming and those we have while awake.  The critic who holds that this premise is false will insist that there are qualitative differences between these experiences.  Let me explore this from one such critic’s point of view.
    Waking life certainly seems to have a sort of clarity and distinctness about it that dreams do not.  “At this moment it does indeed seem to me that it is with eyes awake that I am looking at this paper; that this head which I move is not asleep, that it is deliberately and of set purpose that I extend my hand and perceive it.” (Des. First Med.)  It feels as though I am perfectly certain when I am awake because of the clear way in which I perceive the things around me.  With intention, and the ability to reflect on what I am intending, I look around the room in which I sit, and it seems very apparent to me that I am in my living room, surrounded by my books and furniture.  In no way does it seem like I am dreaming, so how could it be possible that I am?  Dreams seem to be more airy or effervescent, less tangible and less distinct.  I don’t feel as though I have as much control over my thoughts when I am dreaming as I do when I am awake, and there is not such a keen intentionality to my reflections as when I am awake.
    The waking world has coherence and consistency, as well.  When I walk outside of my home, I can always expect to see my neighborhood around me as it was the day before.  When I interact with people, they maintain their particular roles in my lives, such my as brothers, sisters, or parents.  Never in the middle of conversation does one suddenly change into the other as sometimes happens in a dream.  The world simply ‘feels real’ to me when I am awake.  Time flows in a forward direction, and one moment coherently leads to the next.  I do not ever have the experience when I am awake that in one instance I am here in my living room, and in the immediate next instance I am in Paris.  Also, the laws of physics also do not always hold true in dreams, which makes them very different from waking life.  How could it ever be claimed that there is no qualitative difference between dreaming and waking life when there seems to be so much evidence to show that they are qualitatively different?To this objection I have a few responses. First, it could be claimed that waking life is not always clear and distinct, coherent and consistent.  Consider someone who has just had their heart broken by a former love.  They may lie in bed for days on end watching reruns of their favorite television show.  At one moment they are aware that it is noon on Friday, and the next moment they are aware that it is six in the evening!  Time has somehow slipped away without that person even being aware that it has passed, but do we want to say that person was then dreaming during those six hours when in fact they were simply watching their favorite show without looking at the clock during the interim?  Certainly not.  Next, consider that during the night an earthquake shook the ground beneath your neighborhood and every home besides your own has crumbled to the ground.  Your home was somehow never affected, and you slept soundly the whole night through until morning.  Wouldn’t you be surprised when you stepped out to get your morning newspaper to see that your whole neighborhood no longer existed as it did yesterday?  Your sense of consistency about the waking world would be tested in those first moments, I’m sure, but we would still not want to say that you had been dreaming because of your experiencing inconsistency in the waking world.
    Another response to this objection could be that, while it is not always the case that dreams are qualitatively indistinguishable from waking life, it only takes one instance of this being so to refute the objection.  We simply cannot deny that there are times when our dreams seem exactly like our waking life!  I have been deceived by dreams in the past.  Even upon my waking, I remained unaware of the deception.  I dreamt extraordinarily vividly that I had had a conversation with someone about a particular topic.  The next time I saw that person, I believed I had that conversation, and even upon their informing me that I was mistaken, I could not comprehend how it could be that the conversation did not take place and that I had dreamt it!  I have even had dreams about waking up in my own bed, walking out to see that I had visitors pulling up in my driveway, and opening the door to greet them.  After greeting them and bringing them into the house to visit with my family, I went back to bed for a few minutes.   I then woke up again in my bed a few moments later.  Upon walking into my living room and expecting to see my company, I stood completely confused about where they had gone, not realizing for quite a few moments that I had dreamt the entire event.
    A final response to this objection is that it could be the case that we are simply wrong about what are in fact the waking world and the dreaming world!  “Once upon a time, I, Chuang Chou, dreamt I was a butterfly, fluttering hither and thither, to all intents and purposes a butterfly. I was conscious only of my happiness as a butterfly, unaware that I was Chou. Soon I awaked, and there I was, veritably myself again. Now I do not know whether I was then a man dreaming I was a butterfly, or whether I am now a butterfly, dreaming I am a man.”(Zhuangzi).  It could just as easily be the case that what we are now calling the dream world is in fact the waking world, and it would then be only in our dreams that we experience things as distinct and clear, coherent and consistent.
    These responses show that this objection is not strong enough to discredit the second premise in the summarized version of Descartes’s Dream Argument, and therefore does not succeed in rejecting the thesis that the Dream Argument leads to a skeptical position.  To claim that waking life has qualities that are different from those experienced during dreaming doesn’t carry this objection far at all.  It is obvious that this can sometimes be the case, but not always.  To assert that waking life is apparent to us on the basis of clarity, distinctness, coherence, and consistency, is not as strong of an assertion as it is intended to be. This objection fails because it is possible that waking life lacks these qualities, and possible that dreams can have these qualities.  They are therefore not sufficient in determining what is an experience of dreaming or what is an experience of waking life.II. The second objection to the thesis that the Dream Argument is enough to lead to a skeptical position is aimed at attacking the third step in the summarized version.  It states that we are often unable to differentiate our experiences, as they are occurring, as being those of dreaming or those of waking times.  An opponent of this would not only lean on the previous objection, claiming that it seems that we know perfectly well when we are awake, but would add to it a very considerable suggestion.  It would be said that it is not out of the ordinary for some people to be able to recognize not only when they are awake, but recognize when they are dreaming, as they are dreaming.  This is referred to as lucid dreaming.  This opponent would then assert that there are no such instances similar to this that anyone experiences while they are awake, so there is no way that any of us is now dreaming.  Let me explore this view further.
    Sometimes it is the case that upon waking, we realize the oddity of what we have just dreamt.  Perhaps it was one of those situations in which outside the front door of our home were the streets of Paris.  Most of the time, while we are dreaming, we don’t recognize anything strange about this and simply go on as though it all makes perfect sense.  However, there are times when our psyche is keen enough to pick up on these occurrences and points out to our awareness that something is not quite right.
    As I have experienced while lucidly dreaming, and as others have also described it, it is as though something tips me off to the fact that something is amiss around me.  My most recent experience was a dream involving walking through the mall.  I was shopping with my spouse, and she stopped at a window to admire something before attempting to catch up with me, as I had continued ahead by a few steps.  I was walking ahead of her by a few paces, which I knew because I had just turned around to see her.  When I turned forward again, I noticed she was walking ahead of me by a few paces!  Now this seemed strange.  I turned around, and there she was!  There were undoubtedly two of her, which is not the case at all (she has no twin sister to cause my mistaking the situation).  It was in this moment that I suddenly felt the oddity of the situation lift as I recognized I must be dreaming.  Shortly after I recognized this, I awoke in my bed, thus confirming to myself that, indeed, I had been dreaming.  Based on this, I immediately see that I have never awakened from my waking life to confirm that I am now dreaming.  It seems then that I am able to differentiate whether my experiences, as they are happening, are within a dream or are part of my waking life.  How could it even be a consideration that it is possible I am now dreaming, when there is no indication that this is so?

    This objection could be refuted in two ways.  First, by showing that there are times during what we are calling waking life in which we experience very odd occurrences that seem a bit out of place in our ordinary conception of things and that make us question reality.  And second, by showing there is a barrier to our knowledge of a true ‘waking’ world, even when we are lucidly dreaming.  I will explain these further.
    First, it is false to say that everything in the waking world makes sense to us.  In fact, there are many instances in which individuals feel confused or disoriented, such as after a traumatic accident or while under the influence of some drug.  While these particular instances may not necessarily lead that individual to believe they are dreaming, these cases are not the only ones in which our intuition about the world around us tells us something is strange.
    Consider the experience of déjà vu.  This is a very common occurrence to some people, and it is perhaps the strongest intuitive evidence an individual could have that there is something uniquely strange about the waking world.  Déjà vu is literally translated as “already been seen”.  During these events, people report having almost psychic like experiences such as being able to predict the next words a person will say, when another person will enter the room, and what that person will be wearing.  Sometimes these experiences last several moments, but they usually are very brief.  To say the least, it is one of the strangest feelings concerning the nature of reality that a person can have without being under the influence of a drug, etcetera.  Wouldn’t this seem to directly correlate to that strange intuition one has during a dream just before they realize they are actually dreaming?  There is something about the experience of déjà vu that is almost unreal, and this could be a very similar to what it is that enables us to recognize our lucidly dreaming.  It follows then that the experience of déjà vu could lead us to think our waking life is actually only a dream.   This brings me to my second response to this objection.
    As was described earlier, when we are dreaming, we more often than not simply accept the strangeness of the events we experience.  We are ignorant to the fact that we are lying in bed in our pajamas when we are dreaming about walking the streets of Paris.  While it is occurring, we don’t find it strange at all to step out our own front door into the streets of Paris, a baguette in hand and a beret atop our head.  It is only upon waking that we see the oddity of the situation.  There exists a barrier to our knowledge of the waking world when we are dreaming.  This shows the instability in the objection that we know perfectly well when we are awake, because it could simply be the case that we are now only accepting what we are calling the waking world as we experience it, and are ignorant to the actual waking world.
    This barrier holds even in the case of lucid dreaming.  While during a lucid dream we become aware that we are dreaming, we are still unable to have knowledge of what the waking world will be like once we awaken!  This shows that if déjà vu does lead an individual to believe they are dreaming, that person cannot claim to have any knowledge about what the actual world may be like.
    This particular response could be objected on the grounds that the content of our dreams is still based on things we have experienced in the waking world.  When I dream of sheep, it is because I have seen sheep in my waking life!  I do not ever dream of new colors, so the colors I see in dreams must be part of the waking world where I have actually seen them. I don’t acquire any new knowledge when I dream, but I seem to acquire knowledge in the waking world, of which I then dream. It follows, then, that if we are now dreaming, our experience will be based on the actual waking world, of which we then have some knowledge, so the dream argument fails to lead to a skeptical position.

This objection would obviously be false for the reasons given in my introduction.  If what we take to be the waking world is in fact part of a dream, it would not matter how similar to the actual waking world it is, because all of our experiences would then be based on false perceptions.  In the case that we have been deceived about the truth of our perceptions, we cannot make any claim to true knowledge.  Just because I see sheep in what we are calling the waking world doesn’t entail my having any knowledge about sheep in the actual waking world.

The objection meant to attack step three of the Dream Argument on the basis of lucid dreaming has failed to show that we can know whether we are now in a waking world. Even if we became aware that we are now dreaming, we could not place any claim to knowledge about the actual waking world.  More likely than this, even, is the fact that during a dream we most often simply accept our surroundings and occurrences as not being anything odd.  It follows that what we take to be the waking world could also simply be our accepting of a dream as nothing odd.  It has then been shown that we cannot distinguish between experiences within the waking world and those of the dreaming world, and the objection meant to refute step three of the summarized argument fails.

Part IV.  Conclusion
In attempting to refute that Descartes’s Dream Argument is strong enough to lead us to a skeptical position, critics have offered some very cogent objections.  Beginning with an attack on the claim that there is no qualitative difference between dreams and waking life, we were faced with the claim that the ‘real’ world is clear and distinct, coherent and consistent, unlike the dreaming world.  This claim, however, fell short of its goal because it has been shown that the dreaming world could be imperceptibly as clear and distinct as the waking world, and that the waking world can sometimes be chaotic and incoherent as some dreams.  It was also shown that we may simply be confused about which may be the dream world and which may be waking life.
After that objection failed, another was presented to show that in lucid dreaming a person becomes aware that he or she is dreaming, and that no such instances such as this happen during waking life.  We are supposed to gather from this that it is then not possible that we are now dreaming.  This was shown to be false with the discussion of déjà vu as a possible instance of this sort, which showed that there are times when the waking world is not as it seems.  This objection was also shown to fail by discussion of the proverbial barrier one is faced with even when dreaming, and that even while lucidly dreaming, an individual has no access to knowledge about the waking world.  With these objections being shown to fail, we can conclude that Descartes’s Dream Argument has succeeded in leading us to the skeptical position that we cannot conclusively claim to have any knowledge of the external world.



Descartes, Rene. Meditations. First Meditation.

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