[Topics: Epistemology, Philosophy of Religion, Skepticism]
Meditations on Descartes:

Examining Objections to the Main Argument of René Descartes’ Meditations on First Philosophy


René Descartes Sketch by M.R.P. - Meditations on First Philosophy, Cartesian Circle

Caricature Sketch by M.R.P.


It is likely the case that no other work of philosophy has had an influence which is at the same time so massive and so different from the intended effect of its writer as Meditations on First Philosophy by René Descartes. In setting out to provide the thinking world with certainty about the accuracy of their perceptions, the reliability of their intuitions about the soul, and the existence of God—Descartes instead accidentally cast a spell of doubt over the ensuing centuries of epistemology and metaphysics.

This occurred because, perhaps regrettably, Descartes did a far better job of demonstrating the all-consuming challenge posed by following skepticism to its logical conclusions, than he ever did of overcoming that challenge. As it happens, I agree with the assessment of most philosophers that Descartes succeeds brilliantly in tearing the world down, then fails miserably in building the world back up. But I have found that my reasons for believing that usually differ from theirs . . . and I have also found that this difference sometimes stems from them not having a solid grasp on the logical structure of Descartes’ Meditations. For instance, the most popular objection to his argument is that it is an example of circular reasoning, and hence blatantly fallacious; that objection is a great example of a misguided response that misunderstands the case being made.

So, I decided to write this article, in order to both provide a clear presentation of Descartes’ argument against skepticism, and to also survey and evaluate an array of objections one might make against it. Now, let us explore together how René Descartes unintentionally left us all so mired in doubt:

Descartes’ Proof of God and the External World:

When we join him for the purpose of this article, Descartes has already broken himself down in terms of knowledge as far as he feels able to go. He has set out to establish what can be known beyond doubt, and has found that most things don’t seem to make the cut, due to a variety of possibilities (such as that one may actually be dreaming, or be under the spell of some demonic deity, or may simply misperceive).

As a result, he has dispensed with his knowledge of the external world, of the body, and even of most abstract concepts. All he has left himself is a sort of last resort—that if he is doubting all this stuff, then he must be a thing that can doubt stuff. Thus, there is, at the very least, something that exists—namely, a doubting (and hence thinking) thing. This is the one notion he feels he can be certain about, can know beyond all doubt: he thinks; therefore he is.

But now that he has (at least hypothetically) reduced his knowledge of reality to just this knowledge that he is some kind of thinking thing, it is time for him to try to build everything else back up. And he gives that endeavor his best shot, which I will now present as clearly as possible. In the interest of that clarity, I will render his attempted proof into a series of simple three-step arguments.

Photo of Laos by Basile Morin - Rene Descartes, Meditations on First Philosophy, Cartesian Circle

Photo by Basile Morin

To begin, Descartes argues that:

(1a) If I am certain about anything, then I understand the condition(s) for certainty.

(1b) I am certain that I am a thinking thing.

(1c) Therefore, I understand the condition(s) for certainty.

From there, he then argues what it is that he understands as being that condition:

(2a) I understand the condition(s) for certainty.

(2b) There is nothing that makes me certain that I am a thinking thing other than my clear and distinct perception that I am a thinking thing.

(2c) Therefore, clear and distinct perception is the condition for certainty that I understand.

The next step toward reestablishing knowledge of the external world is the first half of his proof of God, which—if it is to follow from what has been established so far—must start with the humble move of merely establishing that he has the concept:

(3a) Clear and distinct perception is the condition for certainty that I understand.

(3b) I have a clear and distinct perception that one of my innate concepts is the concept of a perfect being.

(3c) Therefore, I am certain that I have an innate concept of a perfect being.

And now for the other half of the proof:

(4a) I am certain that I have an innate concept of a perfect being.

(4b) An innate concept of a perfect being could not come from any imperfect being(s), nor from a merely potential perfect being.

(4c) Therefore, the origin of my innate concept of the perfect being is the actual perfect being, God, and thus the being in question exists.

At this point, Descartes goes on a tangent to argue that he himself could not exist unless he was created and continually sustained in reality by God, but that is a separate second argument for God’s existence (which does not depend on his deduction of the thinking thing across the first two meditations) so we will leave it aside. And finally, his proof of the external world:

(5a) God, the perfect being, exists.

(5b) Deception is an imperfection.

(5c) Therefore, God does not practice deception.

First Edition Title Page of Meditations on First Philosophy by Rene Descartes - Cartesian CircleFrom here, he’s off to the races. If there’s an actual supreme perfect God behind the universe, and that God is not a deceiver, then by using his God-given faculties properly Descartes can become certain of many of the pedestrian perceptions and concepts that he methodologically doubted at the outset. Some fine details remain for Descartes to work out in the later meditations, but as a result of argument (5)—which says that God exists and would definitively not allow the sorts of mystical deceptions which grounded his most profound earlier doubts—the world really exists, and is roughly as it appears to him to be.

So, he ultimately writes in the sixth meditation: “I fail to see why God cannot be understood to be a deceiver, if [the ideas of sensible things] proceeded from a source other than corporeal things. For this reason, corporeal things exist” (440).

My Minor Objections to Descartes’ Meditations:

Before digging into this argument’s big issues (advanced by myself and others), here’s a quick list of minor possible problems that stand out to me when surveying the foregoing premises and conclusions:

Premise (1a) may be false, as it may be overly hasty to declare that one understands the true nature of certainty itself simply because one feels certain of something.

Premise (3b) may be false, as (in a sentiment related to common objections to Anselm’s ontological argument[1]) it may be the case that the ostensible concept of a perfect being possessed by Descartes and the true concept of a perfect being are two separate concepts.

Premise (4b) may be false, as it seems conceivable that perfections and infinities could be theorized by extrapolation from near-perfections and vast quantities. Descartes tries to brush away that objection by saying “there is more reality in an infinite substance than there is in a finite one” (425), but that response relies on a potentially dubious hierarchy of ‘degrees of reality’ among different real beings; a transient thing and a permanent thing, or an imperfect thing and a perfect thing, may actually all be ‘real’ to the same extent.

Premise (5b) may be false, as there could be no connection between our moral intuitions about deception and the true nature of perfection. Many solutions to the problem of evil over the years, in fact, have been advanced by religious philosophers who feel that God may be justified in directly bringing about evil in the short-term—provided that doing so is the only way for God to bring about outweighing good in the long-term. Descartes himself nods in that direction in the fourth meditation when attempting to account for the apparent errors in thought committed by humans.

Now, why do I call these points that stick out to me after a cursory inspection “minor objections?” It is not because they would fail to be disruptive to the argument if successful. Rather, I call them ‘minor’ in this context for two reasons: because they merely point out that certain claims may be false (the relevant claims may yet be true), and because they are all objections with which Descartes was personally familiar. They are all either mentioned within the Meditations, or else number among the objections Descartes received from the group of contemporary philosophers and theologians to whom he distributed the work prior to publication. So, they’re objections that Descartes himself knew about and did not consider to be cause for reworking the project. And at any rate, if it so happens that those premises are true, then these objections fail. Let us turn, then, to objections that make stronger claims.

Others’ Objections to Descartes’ Meditations:

Portrait of Pierre Gassendi by Louis-Édouard Rioult - Rene Descartes, Meditations on First Philosophy, Cartesian Circle

Portrait of Pierre Gassendi by Louis-Édouard Rioult

Among other philosophers, discussion has often centered around possible objections to the core assertion that constitutes (1b), which is basically a restatement of his argument that ‘I think; therefore, I am.’

People have variously argued that Descartes is overstating his case in saying it is ‘him’ doing the thinking (which we could call ‘the ego objection’); that he is justified in saying he is a thinking thing on the relevant grounds, but not certain, as certainty requires something more than justification (‘the uncertainty objection’); and that his use of language to think of and express the argument undercuts the idea that he was ever doubting the external world in the first place (‘the linguistic objection’).

Now, despite their popularity, I don’t personally think these are the best possible objections to the Meditations, and I will now briefly treat why I feel that way.

As to the ego objection, I’m not convinced by those who follow Pierre Gassendi in asserting Descartes shouldn’t say “I,” because they feel it may be something other than him doing the thinking. I feel Descartes would be perfectly happy to respond, “Whatever partial or whole thing is doing the thinking—I am content to refer to that as ‘I.’” Even if someone were to say that perhaps the thoughts are somehow self-sufficient and do not necessarily inhere in a separate something, it would still be possible to say, “Alright, then ‘I’ am, if nothing else, that set of self-thinking thoughts.” The core of the assertion, that thinking entails the existence of something, stands strong.

The uncertainty objection—reminiscent of one of Thomas Hobbes’ responses to the second meditation—is the one that hits nearest to my own major complaint about the argument. As a result, I am receptive to the idea that Descartes confuses justification and certainty (because clear and distinct perception may only provide justification). But with that being said, I share Descartes’ intuition about being certain of something existing as a result of mere thought—so for me there is forcefulness to the claim that he is not only justified in saying it, but also certain of it. Rather, it’s whether clear and distinct perception is truly how he has become certain of it that I will be addressing with emphasis further along. (And I’m not talking about my earlier minor objection regarding Descartes’ understanding of certainty in (1a).)

As for the linguistic objection: even though Descartes does allege that he is truly denying all fallible knowledge, for the purposes of advancing his arguments I don’t think a ‘genuine doubt’ that is troubling to him is actually required. For the philosophical exercise, hypothetical doubt will do. In that sense, for the linguistic objection to succeed, they would have to claim that it is actually impossible to doubt everything due to the involvement of language (which does seem to be Wittgenstein’s position). Yet, even then, it seems to be conceivable that one could experience a sensation of doubt which is ‘primal’ or emotional, metaphysically prior to any expression or understanding of it in language—even if the only way to advance from that feeling to description of that feeling is by way of some form of language.

Print of Thomas Hobbes by unknown artist - Rene Descartes, Meditations on First Philosophy, Cartesian Circle

Print of Thomas Hobbes by unknown artist

But let’s set aside all of this quibbling! Maybe all or some of the issues presented in this and the previous section are genuine problems for Descartes’ argument, and maybe they aren’t. But we should skip to the good stuff.

In the introduction of this article, I alleged that the main complaint lodged against the later chapters of the Meditations is that they employ circular reasoning, and I further claimed that it is actually untrue that they employ circular reasoning in a genuinely problematic way. I also alleged that, although that oft-bandied flaw fails, I nevertheless feel there is a major flaw that derails Descartes’ argument. Let’s take a look at each of those claims in turn, starting with ‘the Cartesian circle.’

The ‘Cartesian Circle’ Objection to Descartes’ Meditations:

There are many across the centuries who have accused the primary argument of René Descartes’ Meditations on First Philosophy of circularity (basing his certainty about God on his clear and distinct perception, and basing his clear and distinct perception on his certainty about God). Like some of the points above, this is a response that Descartes received during his lifetime—from Antoine Arnauld, among others. And although Descartes’ own rebuttal to this accusation of circularity failed to prevent the popularity of the accusation through the ensuing centuries (and even up to today), the accusation is nevertheless faulty.

It is not actually the case, strictly speaking, that Descartes bases his clear and distinct perception on his certainty about God. Clear and distinct perception is introduced into the argument on its own as a freestanding provider of certainty, separate from the later introduction of God. Notice that God does not appear in arguments (1) and (2) above.

Now, in retrospect, further along, toward the end of the fifth meditation, Descartes does proclaim that the relationship between certainty and clear and distinct perception is provided by God: “[. . .] once I have perceived that there is a God—because at the same time I also understood that all other things depend on him—and that he is no deceiver, I then concluded that everything that I clearly and distinctly perceive is necessarily true” (436).

But if he had never applied the concept of God to the entirety of his system in that way, and thus stayed at the earlier stages of the argument—he would forever have remained just as content with clear and distinct perception being both his standard of certainty, and the source of his proof of God.

To be clear: I definitely agree that it’s specious for him to retroactively say God is the guarantor of the connections among clarity, distinctness, and certainty. Even if he claims (in that same portion of the fifth meditation) that God is only needed to guarantee the memory of clear and distinct perceptions, and not to guarantee their accuracy when they are present in the moment—that is still tantamount to him saying that, at each stage of his proof of God, the preceding argumentative stages maintain verification in his head due to God.

Recycling Symbol by Gary Anderson - Rene Descartes, Meditations on First Philosophy, Cartesian Circle

Universal Recycling Symbol originally by Gary Anderson

But that specious reasoning is just one aspect of the later segments of his arguments, branching off and ‘circling back’ problematically. That rounded, rotten branch isn’t actually necessary for his overall project to move from point A (Descartes’ establishment of certainty of the thinking thing) to point B (Descartes’ proof of God based on that certainty) to point C (Descartes’ proof of the external world based on that God).

So, if folks are content to acknowledge that the circular reasoning employed by Descartes is in a minor and ultimately unnecessary logistical quirk retroactively applied to his argument, then by all means they can carry on mocking him for the mistake—and can even carry on calling this smaller problem the Cartesian Circle if they so choose.

Still, I do think folks wielding the Cartesian Circle as an objection to the entire argument Descartes is making, though ultimately mistaken, are in the neighborhood of his biggest error. But they’re mainly taking issue with Descartes’ eventual usage of the concept of God, when it’s the other half of the equation—clear and distinct perception—that I think houses the biggest problem.

My Major Objection to Descartes’ Meditations:

With the exception of the Circle, all of the objections described in the foregoing sections are potentially successful rebuttals to Descartes’ overall argument—in the sense that they at least call into question some important premises. Yet, in my opinion, none of them are obviously fatal to Descartes’ position. For people who share his intuitions as he moves from premise to premise, the argument still seems to succeed.

But in actuality . . . I don’t think the argument succeeds. Not even for that group of like-minded people. I think it straightforwardly fails even for those who dismiss all of the earlier issues detailed here, because argument (2) is unsound within the context of the Meditations.

In (2b), Descartes makes an assertion about the origin of his certainty that he himself has shown to be false through his earlier establishment of that certainty.

That is, Descartes doesn’t actually present his argument that he is certain of being a thinking thing via a description or demonstration of clear and distinct perception, as some kind of bare fact or exclusive origin.

Rather, Descartes’ actual argument is that he can be certain that he is a thinking thing because it is impossible for the situation to be otherwise—that even if he were in doubt in every particular about every last detail of himself and everything else, that there would still have to be something doing the doubting. In fact, in part because of its utter simplicity, I believe it to be the best argument he makes in all of the Meditations: the thinking thing doubtless exists, as there is no consistent way in which to doubt that there is doubting happening. Denying that sentiment, for instance by thinking ‘I do not exist,’ is an immediate self-contradiction. Necessarily, if a being can form or negate any proposition, then in some way, shape, or form that being exists. Thus, he writes toward the end of the second meditation:

[. . .] if I judge that the wax exists from the fact that I see it, certainly it follows much more evidently that I myself exist, from the fact that I see the wax. For it could happen that what I see is not truly wax. It could happen that I have no eyes with which to see anything. But it could not happen that while I see or think I see (I do not now distinguish these two), I who think am not something. (419)

But herein lies a major problem for argument (2). After all, that method of establishing the situation means that the real ‘condition for certainty’ Descartes has demonstrated is not clear and distinct perception, but rather the impossibility of error—or at least the inconceivability of error. The argument’s only premise is the thought “I think,” so negating its only premise is self-contradictory.

Hence, argument (2) should be rewritten in such a way as that it would provide (2c) in the following form: ‘Therefore, the impossibility or inconceivability of error about something is the condition for certainty that I understand.’ This would in fact be very appropriate, as it would match much closer with Descartes’ remarks in the first and sixth meditations about his motivations for employing his method of radical doubt.

Unfortunately for Descartes, this correction kills his attempt to build back up knowledge of the external world as soon as his proof of God begins—because it is not impossible or inconceivable for him to be mistaken about having a true innate concept of a perfect being. Indeed, Descartes repeatedly proclaims that the concept itself falls short of true perfection as a step in his proof (for humans and their ideas are imperfect, and, he argues, the source or cause of the imperfect must eventually be the perfect). If he were to instead say that the thinking thing could perfectly contain the concept of perfection, suddenly it would seem by Descartes’ own later reasoning in argument (4) that the thinking thing simply is God.

Now, don’t get me wrong: he does argue (or at least further assert) that clear and distinct perception is the criterion of certainty more as the sections go by. Thus, in the fifth meditation Descartes writes: “[. . .] indeed, whatever proof I use, it always comes down to the fact that the only things that fully convince me are those that I clearly and distinctly perceive” (435). But by then, he has already admitted back into his mind as objects of such clear and distinct perception many of the concepts he had previously doubted—on the strength of his kernel of certainty regarding the thinking thing, whose forcefulness was derived otherwise.

I am perfectly happy to agree that Descartes does clearly and distinctly perceive the concept he knows as perfection. But unless he’s willing to grant that perfect knowledge of perfection could be extrapolated from imperfect knowledge of perfection (which would be equally devastating for his project), he does not thereby know the concept to truly represent perfection. He ‘clearly and distinctly perceives’ that it does, but he does not ‘know with the impossibility or inconceivability of error’ that it does.

Here’s an example of him affirming that this is the case, when he points out that humans are fundamentally incapable of truly comprehending infinitude:

[The idea of God is] an idea that is clear and distinct in the highest degree; for whatever I clearly and distinctly perceive that is real and true and that contains some perfection is wholly contained in that idea. It is not inconsistent to say that I do not comprehend the infinite or that there are countless other things in God that I can in no way either comprehend or perhaps even touch with thought. For the nature of the infinite is such that it is not comprehended by me, who am finite. (425)

Descartes lacks the certainty about the concept which was supposed to provide the power of the entire exercise.


Venus, as seen by NASA's Mariner 10 - Rene Descartes, Meditations on First Philosophy, Cartesian CircleThe argument covered here is not the only dubious portion of Descartes’ Meditations on First Philosophy. For instance, in the sixth meditation Descartes famously argues that two things that can be clearly and distinctly perceived as independent of each other by a careful and rational person are therefore separable or even separate. This forms a part of his set of arguments for mind-body dualism.

Yet other philosophers have been quick to point out that it is perfectly straightforward for someone to “clearly and distinctly perceive” two things as separable and conceptually independent, when in fact the two are simply different aspects of the same entity. The classic example is a pair of distinct conceptions of the planet Venus as ‘the morning star’ and ‘the evening star.’ Those conceptions are consistently separable in imagination, just as Descartes observes the mind and the body to be; but the idea of either ‘star’ actually surviving the destruction of the other due to that imagined separability is obvious nonsense.

What sets the primary argument covered throughout this article apart from such others is that it is of paramount importance to the entire structure of the project. Chiefly residing within Descartes’ third meditation, it holds the special distinction of being the central argument of the work; it is the crucial link that ties the skeptical deduction in the first two meditations to the anti-skeptical proofs and clarifications in the last three meditations. Thus, considering possible flaws of that argument is vital when attempting to understand and evaluate the work as a whole. In the end, the weaknesses of this argument in particular (especially in comparison to the compelling strength of the skepticism that precedes it) can account for the ironic legacy of René Descartes’ epistemological project—namely, the cloud of doubt which the faithful rationalist cast over the ensuing generations.


[1] In fact, Descartes does present his own version of the classic ontological argument further along, in the fifth meditation, with his version involving the claim that ‘existence’ is one of the perfections that must constitute the idea (and thus the reality) of the supreme perfect being. Thus, existence, Descartes argues, is inseparable from God’s essence. The usual set of replies to the ontological argument remain valid in confronting Descartes on this point.

Work Cited:

Descartes, René. “Meditations on First Philosophy in which the Existence of God and the Distinction of the Soul from the Body are Demonstrated.” Translated by Donald A. Cress. Classics of Western Philosophy 3rd Ed, pgs. 405-445. Edited by Steven M. Cahn. Hackett, 1990. Print.

[Topics: Epistemology, Philosophy of Religion, Skepticism]
Meditations on Descartes:

Examining Objections to the Main Argument of René Descartes’ Meditations on First Philosophy

was last modified: April 13th, 2023 by Daniel Podgorski
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