Descartes' Methodical Doubt and Philosophical Principles

Cartesian Methodical Doubt

The Nature of Methodical Doubt

Methodical doubt is an essential method of Cartesian philosophy, aiming at the radical foundation of knowledge by rejecting all beliefs that may arise in doubt. The practice of methodical doubt calls into question not only the value of the senses but also that of deductive reason. The physical world, including the external body, does not resist the actual methodical doubt.

Only the Cogito resists the ravages of methodical doubt. This method was used by Descartes for the discovery of the Cogito, a concept that expresses, on the one hand, the first, whole, and absolutely true truth ("I think, therefore I am"), and secondly, the fact that this truth specifically concerns the self-conscious mind.

Methodical doubt, especially Descartes' criticism of the senses, served to defend the intangible nature of the mind. If all bodies are doubtful, including one's own, but one's mind is not, then the mind must consist of something different from physical reality. Minds are thinking substances (res cogitans), distinct from extended body substances (res extensa).

Descartes' Rules of Method

Descartes' method outlines four fundamental rules:

1. Rule of Evidence

   This is the first and most important rule of the method. It consists of accepting as true only what is presented with "clarity and distinction," that is, with evidence. It involves the exercise of intuition. This rule leads to systematic doubt, and after its application, to strict science or knowledge.

2. Analysis Rule (Resolution)

   This research method consists of dividing each difficulty encountered into as many parts as possible, down to the simplest elements, whose truth can be established by an act of intuition. In the Discourse on Method, Descartes presents this as the second rule. Its assertion is to break down the complex into its constituent elements.

3. Synthesis Rule (Method of Composition)

   This rule involves proceeding with an order in our thoughts, ranging from simple and easy-to-learn objects to the knowledge of the most complex and obscure. In the Discourse on Method, Descartes presents this as the third rule of method. It recommends starting with first principles or intuitively perceived simple propositions (which are reached by analysis) and inferring other propositions in an orderly manner, ensuring not to skip any steps and that each new proposition truly follows the precedent.

4. Enumeration Rule (Review Rule)

   Descartes lists this as the fourth rule in the Discourse on Method. It involves carefully reviewing each step of our research to ensure nothing has been missed and no error has been committed in the derivation.