我的奮鬥

The Epistemological Meaning of Descartes’ Ontological Argument

The famous Cartesian Circle has long been regarded as a scandal for Descartes’ philosophical project of establishing the foundation of knowledge. As a matter of fact, there are passages right in the Meditations where the lamentable effect of that circle can be easily apprehended. One example is the fourth paragraph in the Third Meditation, where one finds it extremely difficult to settle the question whether or not it is necessary to know that God exists and is veracious before the truth of any clear and distinctive perception can be accepted. Another example that reveals this predicament even more succinctly is Descartes’ claim, in the Fifth Meditation, that

And so I very clearly recognize that the certainty and truth of all knowledge depends alone on the knowledge of the true God, in so much that, before I knew Him, I could not have a perfect knowledge of any other thing.

Here, Descartes seems to be denying the validity of his prior knowledge which serves to lead him eventually to the recognition of God, and thus be susceptible of a certain kind of self-contradiction.

Despite the formidable difficulties involved, however, philosophers sometimes tend to be inadvertent in formulating the Cartesian Circle. For example, here is a most barren version of the alleged circularity of Descartes’ reasoning. According to this kind of reading, Descartes first claims that we clearly and distinctly perceive that God exists and therefore know that God exists, and then, he in turn claims that only the very existence of God guarantees that our clear and distinct perception is knowledge. A circle is thus easily formed, and it is blatantly vicious. And as for this kind of interpretation of Descartes, I have no other response but to suggest that it is highly incredible for, as Keith DeRose would say, an eminently smart person such as Descartes to commit himself to a silly mistake like that.

Moreover, it is not sufficient to merely rid Descartes out of the circular form of his reasoning, if one is trying to appreciate the true value of the Cartesian enterprise of epistemology, and what is required is a serious consideration upon the content of that reasoning, i.e. the appeal to God as one of the ultimate sources of our knowledge, which never seems so untimely until the present days. The question is basically this: Does any significance of this part of Descartes’ project still remain in a secularized world such as the one we are living in here and now, and if so, how are we to understand that? To be sure, this greater concern is what genuinely motivates the present discussion.

 Hence, in what follows, I shall first attempt to explicate what seems to me to be the most promising proposal for a resolution to the problem of Cartesian Circle. The proposal under consideration is that of Ernest Sosa’s, presented in his paper “How to Resolve the Pyrrhonian Problematic: A Lesson from Descartes”. Then, I shall approach that proposal in terms of Laurence BonJour’s coherence theory of justification with regard to empirical knowledge. The reason to adopt this line of thought is that, so far as I can see, the latter theory indeed suffices to bring the tenor of Sosa’s interpretation to the fore, and, more importantly, to illuminate the problem to be expected in this interpretation of Descartes. And this would lead directly to, at last, my own way of understanding Descartes’ ontological argument, especially the proper role it plays in his whole project. There, I shall try to make as clear as I possibly can the reason why “God” is needed in an epistemology still intriguing and fascinating even nowadays.

I.

 Sosa’s proposal is based on a criticism of what he labels as a “rationalist foundationalist” interpretation of Descartes, which is best defended by James Van Cleve in his paper “Foundationlism, Epistemic Principles, and the Cartesian Circle”. According to this interpretation, to begin with, a standard statement of the Cartesian Circle is that Descartes seems to be committed to each of the two following propositions:

(1)  I can know for certain that (p) whatever I perceive clearly and distinctly is true only if I first know for certain that (q) there is a veracious God.

(2)  I can know for certain that (q) there is a veracious God only if I first know for certain that (q) whatever I perceive clearly and distinctly is true.

Put this way, the Circle implies that nothing turns out to be really known, for the knowledge of (p) presupposes that of (q), and vice versa. In a footnote, Van Cleve also offers a more general formulation of the Circle so that we can see the problem more straightforwardly: how can I know any epistemic principles unless I first know some other propositions from which to derive them? But how can I know those other propositions unless I first know some epistemic principles?

 Now, Van Cleve’s way out of the Circle is to distinguish the two senses of the ambiguous expression “I am certain of the truth of clear and distinct perceptions”. Indeed, that phrase can be used to express either of the two propositions:

(A)  For all P, if I clearly and distinctly perceive that P, then I am certain that P.

(B)  I am certain that (for all P, if I clearly and distinctly perceive that P, then P).

And the point of this distinction is that (A) could be true even though (B) were false. This is because obviously (B) requires more than (A) in that the former presupposes the possession of the concept of clear and distinct perception while the latter does not.

 Once the distinction is made, we shall notice immediately that (B) need not be true at the outset of Descartes’ project. It is not necessary at all for me to be certain that all clear and distinct perceptions are true in order to know the existence of a veracious God. To do that, it suffices for me to actually possess some clear and distinct perceptions, whether these being endorsed by any general principle such as (B) or not. Therefore, if (A) is true, my clear and distinct perceptions would provide me with the premises I should need to prove the existence of a veracious God, and so far as that proof is accomplished, the knowledge of the existence of a veracious God must in turn guarantee the general principle of (B), so that we can be even more confident of trusting our initial clear and distinct perceptions.

 Back to our (1) and (2), how then are we to deal with the original Circle? Based on the distinction above, if (B) need not be true at the outset, and, as Sosa suggests, “knowing for certain” here could be viewed as referring to the highest grade of knowledge, then we may simply deny (2) as false while recognizing the truth of (1). Thus the Circle evaporates. And this is how the rationalist foundationalist interpretation resolves the problem.

  Unfortunately, this interpretation remains unsatisfactory. One thing to be first noticed is that it does not really go in accord with Descartes’ own writing very well. As indicated by Keith DeRose in his “Descartes, Epistemic Principles, Epistemic Circularity, and Scientia”, if Van Cleve were right, Descartes never had  to cast doubts on any particular proposition, e.g. 2+3=5, so long as it is clearly and distinctly perceived. But there is evidence in the First Meditation which shows that even his clearest and most distinct perception could go wrong:

Moreover, I judge that other men sometimes go wrong over what they think they know perfectly well; may not God likewise make me go wrong, whenever I add two and three, or count the sides of a square, or do any simpler thing that might be imagined?

Or, as Sosa observes, in the Third Meditation, Descartes claims that

For if I do not know this [whether there is a god and, if there is, whether he can be a deceiver－according to the context], it seems that I can never be quite certain about anything else.

And this claim appears definitely to call not only (B), but also (A) into doubt. That is why Sosa concludes that not even (A) can be established to provide the premises needed for the further deduction of the existence of a veracious God. The rationalist foundationalist account is therefore rendered at least highly suspicious.

 Moreover, Sosa raises a much more general difficulty that has to be confronted by any such interpretation of Descartes as foundationalist: first, the proposition that there is a veracious God can not be known by means of clear and distinct perception intuitively. But then, if I cannot know anything unless I know that there is a veracious God, how am I supposed to deduce that proposition? It seems that after all the existence of a veracious God must be both one of the premises and the conclusion of the very same inference. And this again involves a circle that is plainly vicious.

 In a word, according to Sosa, failing to realize that for Descartes clear and distinct perception is not sufficient for knowledge of the highest epistemic status, i.e. scientia, the foundationalist interpretation recognizes only one level of knowledge in Descartes’ project, and so runs counter to the passages above mentioned and turns out still enmeshed in the Cartesian Circle.

  In many important aspects, as he acknowledges in a note, Sosa’s own way to overcome this difficulty is anticipated by DeRose, who has offered a so called “Two-Level Solution” to the problem. The idea of the solution is this. If we admit that in his project, Descartes’ goal is to finally attain scientia or perfect knowledge, we see immediately that clear and distinct perception of truth is necessary but not sufficient for scientia. What else is required? DeRose’s answer is that one also has to clearly and distinctly perceive to be true the general principle that whatever one perceives clearly and distinctly is true. Thus, there are in fact two levels of certainty. For the lower level, clear and distinct perception might be enough. But in order to reach the higher level of sicentia, we have to clearly and distinctly perceive the truth of the above general principle. Given such a distinction of the two levels of certainty, Descartes’ misgiving concerning particular clear and distinct perception is rendered comprehensible－the worry is directed against the lower level, not scientia itself.

 In addition, as for the original Circle, DeRose demonstrates that in the above (1) and (2), if we replace “know for certain that” with “have scientia of”, we can deny both of (1) and (2). This is because one need not have scientia of (p) for the sake of (q), and vice versa. So long as one eventually comes to clearly and distinctly perceive that (p) is true, everything else (including (p) and (q)) one has clear and distinct perception of becomes scientia once and for all.

 In light of DeRose’s Two-Level account, we may now well appreciate Sosa’s own solution to problem of the Cartesian Circle. First, Sosa gives the name “cognitio” for knowledge at the lower level, and reserves the term “scientia” for the higher level. Next, he reformulates the above (1) and (2) as the following:

(1’)  I can have certain scientia that (p) only if I first have certain cognitio that (q).

(2’)  I can have certain scientia that (q) only if I first have certain cognitio that (p).

So articulated, (1’) and (2’) are compatible, and can both be affirmed with perfect sense. More importantly, up to this point, not only a vicious circle no longer threatens anymore, but the ambiguity in Descartes’ writing and the perplexity along with it is dispelled. Here, it should be unnecessary to go through all the complexities of the previous discussion again, and I shall restrict myself to a simple remark upon Sosa’s picture of the Cartesian epistemology.

  Sosa’s insight into that epistemology is best illustrated with his placing Descartes’ project in the context of Pyrrhonian problematic. According to Sosa, what Descartes really wants is a defense against skeptical doubts about his intellectual faculties, and only by means of some theological reasoning that yields an epistemic perspective on this world (he himself included) he can finally feel confident of these faculties. So the picture is roughly as follows. It is a quotation of Sosa’s beautifully written paragraph in full length, and there is nothing better I can employ to end this section:

In the barest sketch, here is how I see Descartes’ epistemological project. First he meditates alone, attaining the kind of epistemic justification and even “certainty” that might be found in an atheist mathematician’s reasonings, one deprived of a world view within which the universe may be seen as epistemically propitious. Descartes’ reasoning at that stage can be evaluated, of course, just as can an atheist mathematician’s reasoning. After all, atheist mathematicians will differ in the worth of their mathematical reasnings. Absent an appropriate world view, however, no such reasoning can rise above the level of cognitio. If we persist in such reasoning, nevertheless, enough pieces may eventually come together into a view of ourselves and our place in the universe that is sufficiently comprehensive and coherent to raise us above the level of mere cognitio and into the realm of higher, reflective, enlightened knowledge, or scientia. There is in none of that any circle that vitiates the project.