Descartes, René (1596–1650)

DOI: 10.4324/9780415249126-DA026-1
Version: v1,  Published online: 1998
Retrieved April 21, 2021, from

7. The validation of reason

With the existence of God established, the next stage in Descartes’ programme is the validation of reason. At the beginning of Meditation III, before proving God’s existence, Descartes notes that the uncertainty that remains is due only to the fact that the meditator does not know whether or not there is a God and, if there is, if he can be a deceiver. This suggests that all one must do to restore reason and defeat the third and most general sceptical argument presented in Meditation I is to prove that there is a benevolent God. And at the end of Meditation III, after two proofs for the existence of God, Descartes concludes directly that this God ‘cannot be a deceiver, since it is manifest by the natural light that all fraud and deception depend on some defect’. But this is not enough. In the course of the deceiving-God argument of Meditation I, Descartes notes that if some deception is consistent with divine benevolence, then total deception would be as well. Since it is undeniable that we do make mistakes from time to time, and are thus deceived, this raises a problem for Descartes: what, if anything, does God’s benevolence and veracity guarantee?

Descartes answers this question by way of an account of error in Meditation IV. Roughly speaking, the mistakes I make are due to myself and my (improper) exercise of my free will, while the truths I come to know are because of the way God made me. More exactly, Descartes asserts that judgments depend on two faculties of the mind, ‘namely, on the faculty of knowledge [or intellect] which is in me, and on the faculty of choice or freedom of the will’. A judgment is made when the will assents to an idea that is in the intellect. But the intellect is finite and limited in the sense that it does not have ideas of all possible things. On the other hand, the will is indefinite in its extent, Descartes claims: ‘It is only the will or freedom of choice which I experience within me to be so great that the idea of any greater faculty is beyond my grasp’. It is in our free will that we most resemble God. In certain circumstances, Descartes held, ‘a great light in the intellect is followed by a great inclination in the will’, and in this way the intellect determines the will to assent. This, he thought, is a proper use of the will in judgment. In this situation, where the intellect determines the will to assent, Descartes talks of our having a clear and distinct perception of a truth. In this case, God has made us in such a way that we cannot but assent. (Clear and distinct perceptions are very close to what he calls ‘intuitions’ in the Rules, as discussed above.) But because the will has a greater extent than the intellect, and is not restrained by it, sometimes things outside the intellect move the will to assent. This is where error enters: ‘The scope of the will is wider than that of the intellect; but instead of restricting it within the same limits, I extend its use to matters which I do not understand. Since the will is indifferent in such cases, it easily turns aside from what is true and good, and this is the source of my error and sin.’ In this way, I am responsible for error by extending my will beyond where it belongs. God can in no way be held accountable for my mistakes any more than he can be responsible for my sins. I cannot reproach my maker for not having given me more ideas in the intellect than I have, nor can I fault him for having made me more perfect by giving me a free will. But as a result of a limited intellect and a free will, it is possible for me both to make mistakes and to sin.

As a result of this analysis of error, Descartes is able, in Meditation IV to assert his famous principle of clear and distinct perception, an epistemological principle to replace the principles that were rejected as a result of the sceptical arguments of Meditation I: ‘If I simply refrain from making a judgement in cases where I do not perceive the truth with sufficient clarity and distinctness, then it is clear that I am behaving correctly and avoiding error. But if in such cases I either affirm or deny, then I am not using my free will correctly’. With this, reason is validated, and the deceiving-God argument answered. Yet, this does not end Descartes’ engagement with the sceptical arguments of Meditation I, and in Meditation VI he also addresses the question of the reliability of the senses, presents a limited validation of sensory knowledge, and answers the dream argument.

The validation of reason, central as it is to Descartes’ project in the Meditations, has one apparent flaw: it seems to be circular. The validation of reason in Meditation IV depends on the proof of the existence of God which, in turn, depends on the proof of the existence of the self as a thinking thing. But evidently we must assume that clear and distinct perceptions are trustworthy in order to trust the Cogito and the proofs for the existence of God that ground the validation of reason – the so-called ‘Cartesian Circle’. Two of the objectors to the Meditations noticed this point, and elicited responses from Descartes, in the Second and the Fourth Replies. Descartes’ answer is not altogether clear. In the Second Replies he remarks, in answer to one such objection, that ‘when I said that we can know nothing for certain until we are aware that God exists, I expressly declared that I was speaking only of knowledge of those conclusions’ deduced by long arguments, and not of ‘first principles’, such as the Cogito Argument. This suggests that Descartes would exempt immediately intuitable (self-evident) propositions from the scope of the doubt of Meditation I, and use them as tools for establishing the premises of the argument that leads to the validation of reason in Meditation IV. There are serious problems with this approach. For one, it seems arbitrary to exempt self-evident propositions from the scope of doubt. Such propositions would seem to fall quite naturally among those most obvious of things that Descartes calls into doubt there; if God could create me in such a way that I go wrong when I add two and three, he could create me in such a way that I go wrong with any other self-evident belief. Furthermore, even if those propositions that are immediately evident are outside the scope of doubt, Descartes’ proofs for the existence of God, necessary premises of his validation of reason, are not self-evident. These apparent problems might be either weaknesses in Descartes’ response, or reasons to doubt that we have understood Descartes correctly in his responses.

The problem of circularity and the obvious problems in Descartes’ apparent answer have elicited numerous examinations of the issue in the commentary literature. It is not clear just what Descartes’ own solution was, nor whether or not there is a good response to the Cartesian Circle. But whatever the answer, the problem is not a superficial oversight on Descartes’ part. It is a deep philosophical problem that will arise in some form or another whenever one attempts a rational defence of reason.

Citing this article:
Garber, Daniel. The validation of reason. Descartes, René (1596–1650), 1998, doi:10.4324/9780415249126-DA026-1. Routledge Encyclopedia of Philosophy, Taylor and Francis,
Copyright © 1998-2021 Routledge.

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