Themes & patterns

The systematic questioning of all beliefs to establish a firm foundation for knowledge, as Descartes proposes doubting everything that can be doubted, including sensory perceptions and mathematical truths, to find indubitable certainty.

The foundational certainty that one's own existence is proven by the very act of thinking or doubting, serving as the first principle from which all other knowledge is built.

The proof of God's existence through rational argument, including the idea of a supremely perfect being and the necessity of a first cause, which Descartes argues is essential for grounding the reliability of human knowledge.

The distinction between the thinking substance (mind) and the extended substance (body), arguing that the mind is immaterial, distinct from the body, and more clearly known than any physical object.

The emphasis on using reason correctly through a clear, step-by-step method to distinguish truth from error, as Descartes outlines rules for conducting one's thoughts and seeking truth in the sciences.

The tension between radical doubt and the pursuit of absolute certainty, where Descartes uses skepticism as a tool to overcome uncertainty and establish a secure foundation for philosophy and science.

The idea that true virtue arises from knowledge and the firm resolution to use reason correctly, with wisdom being the supreme good that guides moral conduct and distinguishes real from apparent virtues.

A rejection of Aristotelian and scholastic philosophy as unreliable, criticizing their reliance on unclear principles and the tendency to follow authority rather than reason and evidence.