Descartes on Mathematical Reasoning and the Truth Principle

The main purpose of this paper is to examine and assess the plausibility of Descartes’ thesis that it is by mathematical reasoning that we ultimately justify the Truth Principle, which is a metaphysical claim. Drawing upon contemporary logic and philosophy of mathematics, the paper argues that Descartes’ understanding of mathematical reasoning, especially concerning infinity, enables him to justifiably conclude that the Truth Principle is indubitable.