What were the four rules of reasoning in Descartes’s method?

In his Discourse on Method (1637), René Descartes outlined four fundamental rules of reasoning intended to guide the search for truth in the sciences and ensure that knowledge is grounded in absolute certainty:

• Evidence: Never accept anything as true unless it is recognized clearly and distinctly as such, carefully avoiding precipitation and prejudice.
• Analysis: Divide each of the difficulties under examination into as many parts as possible, or as may be required for their better solution.
• Synthesis: Conduct thoughts in a specific order, beginning with the simplest and most easily known objects and ascending little by little to the knowledge of the most complex.
• Review: Make enumerations so complete and reviews so general that one is certain nothing has been omitted.

These rules reflect Descartes’s commitment to a mathematical approach to philosophy, prioritizing reason over sensory experience to establish a firm foundation for knowledge.12