Descartes’ Method: Rules, Doubt, and ‘I Think, Therefore I Am’

The Method

Rules guaranteeing the acquisition of clear knowledge.

The fundamental rules of the method are:

1. Rule of Evidence: Accept as true only what is presented with evidence (intuition). This leads to methodical doubt and establishes knowledge as a strict science. In “Principles of Philosophy,” Descartes states we never mislead if we only describe judgments based on clear and distinct knowledge. Error arises from judging before having accurate knowledge; the will can go beyond clarity and distinction, leading to error. Descartes believed errors stem from the misuse of our will.

2. Rule of Analysis: Divide difficulties into the simplest elements to reach “simple natures.” Complex propositions become understandable by observing their dependence on simpler ones. In “Meditations,” Descartes notes this is also a good teaching method, showing how something was discovered and proving complex propositions’ truth. The elementary proposition arrived at by analysis, from which the truth of complex propositions is proven through synthesis, is the cogito, whose truth is shown by intuition.

3. Rule of Synthesis: Order thoughts from the simplest to the most complex. Start with intuitively simple principles and deduce other proposals in an orderly manner, ensuring no steps are skipped. While analysis is the method of discovery (used in “Metaphysical Meditations” and “Discourse on Method”), synthesis demonstrates what is already known (employed in “Principles of Philosophy”).

4. Rule of Review: Carefully review each step of the research to ensure nothing is missed and no errors in deduction have been made (mentioned in “Discourse on Method”).

Methodical Doubt

Descartes’ method to prove the truth of beliefs and discover a truism.

Basic features of methodical doubt:

1. Methodical: Not to be confused with skepticism as a philosophical movement.

2. Universal: Questions absolutely all knowledge, including common sense, perception, scientific research, and mathematics.

3. Hyperbolic/Exaggerated: Radical; question what seems true if any doubt exists.

4. Consequence of the First Rule: Accept as true only what is presented with absolute clarity and distinction.

5. Valid at the Time: A moment of doubt (e.g., questioning if we are awake or dreaming, even doubting mathematics). After discovering the cogito and proving God’s existence, these doubts are overcome.

6. Does Not Discover New Truths: It validates existing beliefs, transforming them into knowledge through rigorous examination.

7. Theoretical, Not Practical: Questions knowledge to find firm foundations; in practical life, probable views are followed.

8. Not Applicable to All Beliefs at Once: Focus on the foundations of belief rather than every single belief.

Key Steps in Methodical Doubt (“Metaphysical Meditations”)

1. First Moment (The Doubt Itself): “Lost world”

a) Doubt the senses
b) Doubt reason
c) Completion of doubt

2. Second Stage: Discovery of the Cogito

a) “I think, therefore I exist” is indubitable
b) We exist as thinking beings

3. Third Time: “Recovery of the World”

a) Demonstration of God’s existence
b) Proof of the legitimacy and objectivity of our cognitive faculties

4. Overall Conclusion: My body, other bodies, other people, and God exist. Discovery of an unquestionable truth (“I think, therefore I am”) and an objective criterion of truth (clarity and distinction).

Cogito, Ergo Sum: I Think, Therefore I Am

Descartes believed sensory information is unreliable. The undeniable fact is thought, which implies existence. Any thinking person must exist. This bridges the spiritual and material worlds, with the pineal gland as the communication point. Thinking allows us to influence the material world. “I think, therefore I am” is an attempt to explain human existence, not necessarily implying absolute freedom.

Error Theory

Doubts, disagreements, and conflicting opinions arise not from an inability to know the truth (skepticism) or the soul’s imperfection, but from the misuse of reason – using reason without a method.