This Week’s Special: Meditation One, in Rene Descartes’ “Meditations on First Philosophy.”

By Daniel A. Kaufman

On tap this week is the (in)famous first Meditation, from Rene Descartes’ Meditations on First Philosophy.  Specifically, I want to draw attention to the logic at the heart of what is – on its own merits – a critique of our claims to knowledge that is both simple and thought-provoking.

Descartes’ self-described aim in the Meditations is to engage in a systematic examination of his belief system, so as to be assured that it rests upon solid grounds.   He begins by entertaining a series of skeptical considerations, each more far-reaching in its scope than the last, and by the end, he has managed to cast doubt on every possible variety of belief, whether grounded in sensory experience or in deductive reasoning.

Whichever of the skeptical scenarios we choose and whether we are talking about the justifications we offer, either for empirically grounded beliefs or for beliefs based in reason, there is a common underlying logic to the critique that they provide.  So let’s examine each in turn.

  1. Belief: It’s raining outside.
  2. Justification: I am looking out of the window, and I can see that it is raining.

In his famous “Dreaming argument,” Descartes points out that one can have exactly the same experience in a dream that one has while awake and that from within the experience, there is no way to distinguish one from the other.  Thus, I can dream that I am looking out a window and seeing rain and that experience can “feel” identical to the experience I have, when I am actually looking out the window and seeing rain.

Consequently, (2) is not sufficient as a justification for (1).  Indeed, it only provides such a justification, if I can also justify the following:

  1. Belief: I am not currently dreaming, but really looking out of the window and seeing rain.

The trouble, of course, is that this belief cannot itself be justified by appeal to other sensory experiences – since it is the validity of my sensory experiences that is under question – but it also cannot be deduced or otherwise justified via reason: there is no way, after all, to prove that I am not currently dreaming.

1a.  Belief:  2+2=4.

2a.  Justification:  Some deductive proof (involving the Peano axioms).  (1)

In his (equally famous) “Malicious Demon” argument, Descartes maintains that it is possible that our minds are being manipulated by a powerful, malicious being, such that we sometimes – or always – reason incorrectly.  Consequently, (2a) is not sufficient as a justification for (1a).  It only provides such a justification, if I can also justify the following:

3a.  Belief:  I am not reasoning incorrectly.

The trouble, of course, is that this belief cannot itself be justified by appeal to reasoning – since it is the soundness of my reasoning that is under question – and it also cannot be justified empirically, insofar as mathematical statements are not known a posteriori.

Too many, when confronting these arguments, have focused unduly on Descartes’ somewhat exotic examples, but they really are entirely dispensable and serve what is essentially an illustrative function.  What both arguments rest upon is recognition of the inherent fallibility of our faculties and of the problem of trying to verify the sound exercise of those faculties, by employing the very same faculties.

Notice something else.  To the extent that our common belief in the external world and more generally, an objective reality – that is, in a world and reality that exists independently of our minds (and thus, our thoughts and experiences) – is grounded in beliefs that come from sensory experience and reason, we clearly are engaged in a massive exercise in circular reasoning.  After all:

  1. Here is a hand. (Holding out my hand)

only provides evidence for

  1. The external world exists. (2)

if I already presuppose the external world’s existence.

If I am a disembodied consciousness, living in a perpetual dream, then having a hand-experience is no evidence at all that there is an external world.

Precisely the same argument can be made on the “reason” side of the ledger.  And so what we are left with is this – precisely the things that we take as evidence that an objective reality exists, only count as evidence, if one already presupposes that reality’s existence.  (3)

Descartes’ solution to these problems, in which he appeals to the divine and the perfection associated with it and its creation, is for obvious reasons unacceptable.  My own view is that problems such as these have no solutions and that the value in engaging with them is rather to disabuse us of various notions we may hold about what we know, how well we know it, how good our reasons really are for the things we claim to know, and the like.


  1. This example of a “proof” for the external world, comes from G.E. Moore’s “Proof of an External World,” Proceedings of the British Academy, 1939.

  1. This is my paraphrase of Crispin Wright’s “I, II, III” argument, in his “Facts and Certainty,” Proceedings of the British Academy, LXXI.





20 responses to “This Week’s Special: Meditation One, in Rene Descartes’ “Meditations on First Philosophy.””

  1. I wonder if a Descartes of today would agree with his original self?

    Today he would have convincing evidence that he is not dreaming about the reality of his body. For instance, he becomes aware that he has been feeling a little off color: tiredness and shortness of breath has been interfering with his mental faculties. He lacks the will to concentrate. His doctor says to him, your hemoglobin is extremely low resulting in a lack of oxygen to the body, including the brain, making you feel the way you do. Since your serum iron is almost non-existent, take these iron pills while we figure out what is wrong. Rene ultimately recovers and is very grateful that medical science had invested the time and effort in gaining an understanding of reality as it is. He is also very impressed at how a simple ailment of the body could affect his view of his surroundings. The reality of his body chemistry, of which he had no inkling, directly affected his mind.

    Descartes of today would be fully aware of the unpredictable unreliability of the senses, but also that scientific experimentation had opened up innumerable vistas of improved understanding of how things are and how they work. Similarly, Descartes would realize that reason is very dependent on individual perspective, but he would also be extremely impressed at the ability of mathematicians, using formal logic, to describe the world as it is.

    Now, it probably does not impress too many by suggesting that we might all be living in a dream. Does it matter? The ‘dream’ is so content rich and has produced so many artifacts, never before dreamed of, it is not empirically significant whether it is real of not. The dream has all the features of a reality independent of our minds. Rational arguments to the contrary now have the burden of proof.

    Perhaps Rene had put de cart before de horse: I am therefore I think.

  2. I must reread, my recollection was that he didn’t regard these things as problems, merely premises to be noted.

    I can’t imagine why anyone would be bothered about these things. It seems to be only a certain kind of scientist who bristles at the idea that they might not really be describing reality.

  3. This seems a great topic for some articles. There is a lot of talk of Cartesian doubt but largely it seems to be ignored as a method. Perhaps realism is not keen of examining its assumptions.

    Liam – Descartes’ doubts will always be just as possible as ever, regardless of medical progress. Nothing has changed or ever will.

    I like the quote that appears (weirdly) in Dennett’s book on consciousness, “Sometimes I think, sometimes I am’ – Paul Valery.

  4. Hi Liam,

    I am not sure why you think that a Descartes around today would not have considered the evil genius of which he speaks creating a deceptive impression of low haemoglobin affecting his mind. He was onlyh concerned that these things were doubtable.

    Don’t forget, also, that he was one of the people who contributed significantly to the mathematcs that is used to describe our world and so perhaps he would not have been so much impressed as gratified.

    And perhaps, hearing physicist conjecture about infinitely large and infinitely long stochastic processes where everything that is not ruled happens,then he would a huge increased scope for the perceived moment being nothing but a random fluctuation or an infinite array of randomly formed evil geniuses conjuring up every possible perceived moment infinitely many times over.

  5. The elephant in the room in Descartes’ meditation is whether or not we can claim anything to be true.

    For some pragmatists (e.g., codicalists), what is (computes to be) ‘true’ (or ‘false’, etc.) is an expression of a particular (coding) language (with its own rules of judgment) that one is using for some purpose, not some entity that is independently, eternally true. That includes ‘2+2=4’ and ‘It is raining’.

  6. Liam: I don’t see how your first paragraph solves anything. What you describe there could easily be a dream someone has.

    Philip: Of course, pragmatism is one of the ways that one avoids the Cartesian challenges. And yet, I still think the doubts are useful, at a less formal, less “total” level. They challenge us to examine our reasons and to be very clear as to the limits of those reasons.

  7. […] elephant in the room in Descartes’ meditations is whether or not we can claim anything to be […]

  8. Liam Ubert,

    Your comment evidences a basic misconception of what kind of argument Descartes is making and the issues it involves. A loose analogy might be, that at a party a man offers me a beer, and I ask whether I should trust him or not, and you tell me, ‘We’ll have a doctor give him a physical exam.’ This promise doesn’t answered the kind of question I am asking; just as analyzing the beer chemically isn’t going to assure me if its of a quality or taste I prefer.

    The condescension you show to Descartes is misguided. Descartes was quite familiar with the developing sciences of his time including microscopy, astronomy, chemistry; I doubt the former military engineer who founded analytic geometry could quite be as gullible as you seem to believe; perhaps there is some kind of move he’s making here that you’ve missed?

    Your final remarks indicate that you may have also missed Dan’s own conclusion: “My own view is that problems such as these have no solutions and that the value in engaging with them is rather to disabuse us of various notions we may hold about what we know, how well we know it, how good our reasons really are for the things we claim to know, and the like.” What you say is true for most of us aware of the ‘dream/reality’ problem, but this is not news; Poe put it more poignantly:

    Thus much let me avow-
    You are not wrong, who deem
    That my days have been a dream;
    Yet if hope has flown away
    In a night, or in a day,
    In a vision, or in none,
    Is it therefore the less gone?
    All that we see or seem
    Is but a dream within a dream.

    I stand amid the roar
    Of a surf-tormented shore,
    And I hold within my hand
    Grains of the golden sand-
    How few! yet how they creep
    Through my fingers to the deep,
    While I weep- while I weep!
    O God! can I not grasp
    Them with a tighter clasp?
    O God! can I not save
    One from the pitiless wave?
    Is all that we see or seem
    But a dream within a dream?

    There’s a difference between saying, ‘I see something wrong with this argument,’ and simply dismissing it as irrelevant, which you seem to be doing here. Descartes’ argument may be irrelevant to a great many matters; but it has had profound usefulness in the fields of epistemology and metaphysics, if only as break-wall to push against. Or is the whole history of Modern philosophy to be dismissed as well? Then we should need to dismiss a great deal of cultural history along with it – including the faith in science that originated in it.

  9. I think it’s good to pay our respects to the great René Descartes. Sure I liked Socrates as a youngster, but this was the man, not Socrates, who gave me a perfectly basic foundation from which to build. The “I think, therefore I am” premise not only provides an ultimate epistemic humility to moderate my thoughts regarding reality, but it also tells me some undisputable things which concern reality itself. It tells me that there is ultimately some sort of existing reality, which I can be sure of since I’m quite sure that I think (which is to say “consciously process information”). Very instructive.

    Permit me to take this premise slightly further. I believe that qualia is something which the non-conscious mind produces for the conscious mind to process. If the non-conscious mind signals for it, though the conscious mind does not process it, then the qualia doesn’t actually transpire. For example, consider being in great pain, but then undergoing anesthesia. Presumably the non-conscious mind continues to provide the pain signals, though as consciousness ends the signals stop being processed. (“Numbness” would be another way to address pain, though this permits consciousness while interrupting the non-conscious mind’s signals for it.) So given this model, qualia itself becomes an indisputable sign of personal existence. Furthermore we might presume that anything which does not consciously process information, such as a computer, cannot know that it exists (even if it does).

    To then go one step further, I believe that qualia happens to be a necessary aspect of consciousness; the punishment/reward which drives its function. Apparently non-conscious minds were not effectively autonomous enough, and therefore evolution did solve “the hard problem of consciousness” by creating good/bad existence (or the experience of qualia), beyond standard irrelevant existence. Thus I sit here today knowing that I, and reality, does exist in at least some capacity. I presume that I am talking to others out there however, though some questions/comments would help.

  10. PhilosopherEric:

    For Descartes, as for Locke, qualia are secondary qualities that exist only in the mind of the perceiver. That said, they are the result of the primary qualities of objects acting upon our senses.

  11. Well Daniel, I can’t blame them for putting a #2 on the mental stuff, and a #1 on the stuff that the mental perceives, since this is simply natural for us to do. Nevertheless all I can truly know is that the #2 does exist, while the #1 may not exist at all, and it most certainly does not exist in the manner that I perceive it to. Surely there is no “color” or “sound” in nature, for example, though these things do seem to be manufactured in my own head somehow. The tree which falls in the forest that no one’s around to hear may indeed change some things, but shouldn’t produce any sound whatsoever.

  12. I can’t help feeling that I hear a clamour of voices floating up from Hades shouting “Well, Duh!” whenever the question of skeptical doubts is raised. We seem to keep rediscovering the idea rather than just listening to those, more than two thousand years ago, who denied any certain knowledge and advised pragmatism and tranquillity in its place.

    But it raises the question, is there any fact of the matter about whether one person might be considered more rational than another. Reason is constantly recommended to us by those who use it as their catch cry and letterhead. Could Richard Dawkins, Daniel Dennett or Brian Cox be considered more rational than, say, Abu-Bakr Al Baghdadi?

    But don’t the champions of reason today ask us to adopt the axiom that no axiom is better than any other? Everything is to be considered on its merits and fitted into a web of belief? As Lee Smolin says, no axiom can be considered to have existed until some human made it up and so none of the facts based on that axiom could be considered to have been true until then, and it can only be said to be true of a certain set of axioms.

    So Baghdadi adopts different axioms than does, say, Dennett, Krauss etc. But none of them can claim to be more rational than him without implicitly claiming that some axiom, such as “that which has been thoroughly and empirically tested by many independent observers is true”, is better than another or even that it is, a priori, true.

    So when people recommend that we conduct our lives upon rational principles, what they really mean is that we should, arbitrarily, adopt certain axioms over others.

  13. Hello. This is my first comment here at Electric Agora.

    Descartes’ arguments (like the problem of induction) are extreme demonstrations of a more general fact: we can’t have complete justifications. In our ordinary empirical inferences the evidence doesn’t entail the conclusion. Even in our deductive proofs we can’t ultimately prove that the steps of our proof are valid. The best we can do is break those steps down into smaller steps, but that process has to stop somewhere. Descartes’ cases just serve to make the absence of complete justifications particularly obvious. They draw our attention to what we usually ignore. The fact that we can usually give partial justifications has kept us satisfied.

    But who told us that we need justifications? If someone tells us that explicitly, we ought to say, “Justify that!”. Any insistence that we need justifications would be self-defeating. We’ve trained ourselves to demand justifications, and that’s led to us feeling uncomfortable when we find we can’t have one. Animals get by perfectly well without justifications, and so do we most of the time. Yes, it’s useful to look for partial justifications when engaging in careful reflection. But we’ve mistaken a useful tool for a necessity.

    Our knowledge doesn’t arise in the first place from justifications or other discursive reasoning. It arises from the automatic workings of mostly non-conscious cognitive processes. These processes work reasonably well because they’ve been honed by evolution and practice. In the end, we have to trust them to do their job. There are things we can do to improve our chances of getting things right, including careful skeptical scrutiny of our beliefs. But, in the end, if our cognitive processes are failing us, that’s just that. Nothing can give me an ultimate guarantee that I’m thinking straight.

    I think we have traditionally tended to take discursive reasoning and arguments as the model for valid cognition, because that’s the aspect of cognition that we observe ourselves using. We have been largely unaware of the non-conscious cognitive processes beavering away under that surface. We’ve mistaken the tip of the iceberg for the base. So we imagine that we can find a base for our knowledge in arguments, and we’re disappointed when we find we can’t.

    Descartes’ attempt to start from a blank slate was bold, but misguided. I am where I am, with beliefs acquired over a long history, not just my own lifetime, but a longer history of human culture and biological evolution. All I can do is subject my current beliefs to whatever critical scrutiny I can manage. That critical scrutiny cannot and need not consist in justifying my beliefs from scratch. There is no formula to follow. I must make a fallible, non-formulaic judgement, weighing up the pros and cons. By trying to start from scratch, Descartes puts himself in the position of needing a pro (a justification). But if we can find neither pros nor cons, we have no reason to change our current position. If I have no reason to think that I’m dreaming or living in the Matrix (beyond the mere possibility in principle) then why worry about such possibilities?

    I should say that I’ve never had (or don’t recall having had) dreams of anything like the verisimilitude of the dreams Descartes describes. If I try to compare my current state with that of my dreams, I don’t at all have the feeling that this state is like that state. I’ve sometimes had brief doubts as to whether a recollected event was real or dreamed, and I resolved those doubts by judging the plausibility of the event. This seems very different from entertaining the possibility that I am currently experiencing dreaming of the familiar sort, which I find myself unable to do. I can entertain the possibility that I’m in the Matrix, or in some unfamiliar sort of altered state which is stipulated to be indistinguishable from my familiar experiences. But dreaming and being awake don’t seem indistinguishable. Proposing that I’m currently dreaming (in the familiar sense) seems rather like proposing that I’m in pain, when I’m feeling quite comfortable and awake.

  14. What has always struck me about the Meditations is how disappointing the proofs of God are.

    Not that I actually expected God to be proved. But I thought that there might be something intriguing and though provoking, given the brilliance of the man and the quality of the first two Meditations.

    But the proofs of God are a real anti-climax.

  15. Descartes’ goal in this meditation on ‘first philosophy’ is to establish a firm foundation upon which to build knowledge and to defend it against skeptics. His description of the undeniable (to himself) fact that he is a conscious individual resonates with us. One can argue with the details of his argument, especially the parts where he invokes a God that would not deceive us. This was perfectly standard in 17th century Europe; it was, in fact, a politically necessary move. Descartes was acutely aware of the consequences of being too direct: Giordano and Galileo were of his time. His body/mind dualism can be seen as an accommodation for the Holy Spirit.

    Descartes’ ontology then was a world that made sense, thanks to a God that would not deceive us, “that all truths were linked with one another, so that finding a fundamental truth and proceeding with logic would open the way to all science. This basic truth, Descartes found quite soon: his famous “I think therefore I am”. (Wikipedia)

    Descartes concluded in his Discourse on Method that he had an adequate solution: clear and distinct thought. Since then we have considerably expanded on his very initial efforts:

    1. We now have much greater insight on the unreliability of the senses. We now understand that what we hear, see, smell and taste are individually unique, incomplete, indirect representations of reality as it is, both external and internal to our bodies. The world as constructed through the senses is subjective and therefore it is impossible to arrive at an agreed upon version of it. This is now well-known but not widely appreciated. Education regarding the utility of our senses would be important. The world of the senses however is our primary mode of existence and is by far the most meaningful interaction that we have, but it is fraught with misconception. We try to compensate by seeking the opinions of multiple observers and by using instruments by which to get an objective measure of phenomena. The extraordinary success of science seems to be directly due to these two moves.

    2. Are we at the mercy of an evil demon or a loving god? Silly as it sounds, it is still possible that either of these entities could find it worth their while to construct this infinitely elaborate delusion in each one of us – or maybe just one of us, but which one? This would seem to be a perfect example of a meaningless question since a definitive answer could never be found. ALL information and knowledge would derive from this completely hidden source, the existence of which, or non-existence, would then be completely undeterminable and irrelevant to the human condition. (This is in fact the problem that the supporters of Intelligent Design can not overcome.)

  16. Hi Richardwein,

    From your inaugural comment here, I do get the sense that we think about this stuff quite similarly. I’ll make a few observations in this regard, and perhaps you’ll consider some of my own associated musings.

    Like you, I’d love for us all to to quit worrying so much about finding “ultimate justification.” Beyond Descartes’ “I think” bit, we should simply never receive any such justification, nor even need it. Apparently instead we take what we think we know (evidence), and then use this to evaluate models that we aren’t so sure about (theory). When a given model does continue to stay consistent with what we think we know, yes it does tend to become accepted for general use. Note here that I’m not simply describing how science works, or even how the human works, but rather how all conscious life, consciously figures things out.

    I love that you’ve given the non-conscious mind its due credit. Perhaps 95% is a reasonable number, though certainly the vast majority of our “gray matter” should simply be a highly advanced computer, or “the iceberg” upon which a conscious tip rests.

    As far as dreams go, I’m very comfortable with the notion that everything which I think I’ve ever perceived, did not actually occur. All I can truly know to be real, is that I do seem to be perceiving various things at this specific moment. But as for the dreams we have while sleeping, apparently the difference you’ve observed is that they are produced by means of an impaired conscious mind. I refer to sleep as a “sub-conscious” state (spoken with a slight pause to help distinguish it from the standard “subconscious” idea). There are also various substances which seem to impair consciousness in their own associated ways, though sleep seems to be the most normal and necessary variety.

    Any thoughts?

  17. Hi Daniel,

    “Descartes’ solution to these problems, in which he appeals to the divine and the perfection associated with it and its creation, is for obvious reasons unacceptable.”

    Argument based on appeals to the absolute, such as have been with us for millennia, is not so obviously wrong if one couches it in the most up to date terms: life on this planet is a coherent whole that has been created on this planet, and perhaps others, through a process of evolution over a period of about 4b yrs. The cosmos itself has been evolving over about 14b. yrs, from a relatively simple singularity to the almost infinite multiplicity of forms that exist now. Humans are the most complex known structures and have the ability to investigate their own astonishing existence.

    The world thus seems to make sense from a ‘common sense’ perspective. Evolution has an apparent purpose – survival. The how, why and wherefore of this process of survival is still for us to figure out. There is clearly no place in our vast universe, where we now learn everything is connected, for mischievous demons bent on confusing us or gods that bestow peace. To introduce these trickster entities is to violate a cardinal rule of clear thinking: No Miracles, No Myths.

    Many are offended by such oversimplifications with justification. The challenges of society, culture and existence are overwhelming and defy any single, reductionist narrative. However, once one understands that the complexities of life are not magically dissolved by a foundational narrative, the various sides could profit by learning from each other. It would certainly be a great boon for humanity if obviously erroneous narratives could be set aside.

    Positing strange disembodied dream states or evil demons sounds like magical thinking. These assertions are neither verifiable nor falsifiable and these states could therefore not exist in human terms on a priori grounds. They should be viewed as irrelevant in any pursuit of human knowledge.

  18. Positing strange disembodied dream states or evil demons sounds like magical thinking. These assertions are neither verifiable nor falsifiable and these states could therefore not exist in human terms on a priori grounds. They should be viewed as irrelevant in any pursuit of human knowledge.


    As I explained in the essay, the exotic examples Descartes uses are entirely dispensable, and the argument remains as strong as ever.

  19. Hi Daniel,

    You say that you can dispense entirely with Descartes’ illustrations, but you still depend greatly on his arguments:

    “What both arguments rest upon is recognition of the inherent fallibility of our faculties and of the problem of trying to verify the sound exercise of those faculties, by employing the very same faculties.”

    And again:

    “1 Here is a hand. (Holding out my hand)

    only provides evidence for

    2 The external world exists. (2)

    if I already presuppose the external world’s existence.

    If I am a disembodied consciousness, living in a perpetual dream, then having a hand-experience is no evidence at all that there is an external world.”


    There is not much difference here with the Cartesian approach. Even our supposed imprisonment by our presuppositions have a Cartesian ring, reminding me of a mischievous demon controlling our minds and completely preventing us from sensing things as they really are independently of our bodies. (Do I detect a whiff of Platonism?) The fact of progress in knowledge provides prima facie evidence that we can break out of the circular argument trap.

    I just have difficulty in seeing why or how a purely rational analysis, eschewing empirical evidence, would be more reliable than a complete analysis, both rational and empiricist, that incorporates all the ever-increasing mountains of available data – a case of don’t confuse me wth the facts?. The same difficulties in terms of our senses and reasoning abilities apply to either approach anyway.

  20. Hi DanK, Sorry for coming in so late. This was one of the more influential pieces for me (regarding epistemology) when I was a young philosophy student. Deconstruction of knowledge to get to its working parts, and so recognition of its limits is very important. Unfortunately his arguments regarding god were clearly flawed, almost special pleading, which prevented it from being the most influential work I read. Nice start, poor finish.

    Robin, you asked “But it raises the question, is there any fact of the matter about whether one person might be considered more rational than another.”

    I think so.

    Your point is true that two contradictory belief systems may be equally coherent and so rational, and no decision of greater rationality possible between them, only preference for supporting axioms. However, that does not mean all “webs of knowledge” are equally “taut” or well put together.

    I would tend to think Baghdadi might have some internal inconsistencies regarding knowledge or evidentiary claims particularly when it comes to deciding between claims based on faith, compared to someone like Brian Cox or Dan Dennett. Greater internal inconsistency may very well be a sign of less rational thinking or beliefs.

    That said, I tend to think this assessment would be more subject bound than for all possible knowledge/thinking. One can be extremely rational about some things, while incoherent on other topics (particularly where one has not spent much time considering or experiencing).

    One might say my argument conflates coherence with rationality and so becomes an argument about semantics or an assumed axiom regarding rationality, but I am uncertain how a concept of rationality avoids some expectation for internal coherence.