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Descartes's Method and the Role of Eternal Truths

  • Author(s): Bruce, Zachary MacKay
  • Advisor(s): Stroud, Barry;
  • Warren, Daniel
  • et al.

I contend that Descartes's infamous commitment to God's free creation of the eternal truths plays an integral role in Descartes's philosophical program. Descartes's primary philosophical goal is to establish a method capable of yielding firm and lasting scientific knowledge. It isn't widely agreed that Descartes has been successful: first, his response to the threat of skepticism appears circular; and second, his account of God's free creation of eternal truths (e.g., mathematical and logical truths) seems to lead to paradox. I argue that neither criticism of Descartes is insuperable. In so arguing, I offer a novel interpretation of Descartes's project that rejects two common refrains of Cartesian scholarship. First, I deny that Descartes is an out-and-out internalist about knowledge and, in so doing, demonstrate that Descartes's epistemic program is not guilty of circularity. Second, I contend that Descartes's commitment to God's creation of the eternal truths is neither an embarrassment for Descartes nor a stand-alone curiosity, but is central to Descartes's epistemic program, modal theory, and scientific method.

In the Meditations, Descartes uses a method of doubt to reveal unshakable foundations upon which one can build scientific knowledge. Descartes's anti-skeptical procedure is commonly thought to be vulnerable to the charge that it is viciously circular. Descartes is accused of relying on a general epistemic principle (viz., the "truth rule": whatever I clearly and distinctly perceive is true) in his argument for the existence of a non-deceptive God, who in turn secures this very principle. In the first section of my dissertation, I explain that Descartes avoids circularity since he is able to achieve certainty and knowledge (cognitio) even before he becomes aware of the foundations of this knowledge. By attaining cognitio of God's existence and non-deceptive nature, Descartes can then make use of the "truth rule" and thereby ascend to perfect certainty and scientific understanding (scientia). In this way, Descartes can be seen to be an epistemic externalist. While Descartes's account thereby avoids circularity, it makes the epistemic advantage of the Cartesian scientist over the "atheist geometer" (an expert who does not believe in God but nonetheless achieves cognitio by using God-guaranteed clear and distinct perception) look quite thin. To fully appreciate the epistemic advantage of the Cartesian scientist - and thus the value of Descartes's epistemic program - one must recognize that God is not only the guarantor of one's cognitive faculties, but also the metaphysical foundation of scientific truths.

A second major objection to Descartes's anti-skeptical and scientific programs focuses on his infamous Creation Doctrine: the doctrine that God freely wills and creates the eternal truths. The Creation Doctrine seems to lead to a paradox: Descartes's claim that God freely wills necessary truths seems to entail that these truths are both necessary (since God willed them to be necessary) and non-necessary (since God could have refrained from willing them). I argue that the sense in which the eternal truths could have been otherwise in no way threatens our certainty and knowledge of that which we clearly and distinctly perceive to be necessarily true.

In the final section of the dissertation, I further examine Descartes's Creation Doctrine. Descartes's goal of scientia involves not merely recognizing what is true, which is sufficient for cognitio, but also having full understanding of the foundations of knowledge and the relationships between truths. Descartes's scientific method thus requires intuitive foundations from which we can deductively arrive at further knowledge. According to this method, by understanding the way in which eternal truths have their origin in God's will and creation, we gain an appreciation of the connections between various truths and arrive at a systematic understanding of the world. Descartes denies that truths in various domains can be fully understood independent of a background of knowledge of simple and evident natures. He hopes to attain a "universal wisdom" and be able to deduce effects from their causes. I provide a demonstration of this method by considering Descartes's deduction of the laws of nature (inertia, collision, and rectilinear motion) from our knowledge of God's nature as immutable, the nature of matter as extension, and the fact that God has created a physical world with variation in its parts.

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