Descartes' Rationalist Method and Cartesian Doubt

The Cartesian Method

In his search for a method, Descartes emphasizes the need to first understand the structure of reason so it can be properly applied to objects of study.

Reason is exercised through two fundamental operations: intuition and deduction. Descartes defines intuition as a "natural light" or instinct—a concept that allows one to know with total clarity, distinction, and absolute certainty. Deduction is the chain of connections established based on concepts known with certainty.

The Four Rules of the Method

The method consists of a series of rules that ensure the correct use of these two mental operations. There are four:

• Evidence: Do not fall into precipitation and only admit as true what is presented to reason as obvious. Clarity and distinction are the hallmarks of evidence: an idea is clear when the mind perceives it without barriers, and distinct when it is separated from any other idea.
• Analysis: Divide each of the difficulties to be examined into as many parts as possible to resolve them better. This breaks knowledge down into the simplest elements to achieve clear perceptions or intuitions.
• Synthesis: Starting from simple and obvious ideas perceived by intuition, use a process of deduction through a chain of intuitions to reconstruct the complex.
• Enumeration: Review and verify the entire process of analysis and synthesis: "By making enumerations so complete and reviews so general, we are sure not to miss anything."

The rules of the method proposed by Descartes require questioning everything and accepting traditional wisdom only if it can withstand criticism. This makes doubt the starting point of his philosophy.

Methodical Doubt

Doubt is a requirement of the method during the analysis phase. Descartes calls into question all commonly accepted knowledge—whether from tradition, faith, or authority—trusting only the reason of the knowing subject. Cartesian doubt has its own specific characteristics:

• It is universal and radical, questioning all certainties, no matter how obvious they may seem.
• It is methodical rather than skeptical. While skeptical doubt is an ongoing state, Cartesian doubt is a tentative and constructive starting point for finding certainty. It is a tool for achieving truth and building philosophy.
• It is theoretical, meaning it should only affect the level of philosophical reflection, not personal beliefs or behavior.

To justify the need for this universal doubt, Descartes puts forward a number of reasons: