Descartes’ Method and the Search for Truth: A Philosophical Inquiry
Descartes’ Method and the Search for Certain Truths
Descartes proposes a new method to discover certain and demonstrable truths in philosophy. This method requires some preconditions: adopting the rigor of the mathematical method, setting aside faith-based beliefs, and rejecting previous philosophical accounts.
Four Rules to Guide Reason
Descartes offers four simple rules to guide the proper use of reason:
- Evidence
- Analysis
- Synthesis
- Verification
There are two types of knowledge:
- Intuition: Immediate knowledge derived from reason, involving clear and distinct ideas.
- Deduction: Connecting and linking simple concepts derived from intuition.
Knowledge begins with intuition. To discover philosophical truths, Descartes adopts the mathematical method, which has two key components:
- Analysis: Separating key elements to reach a first principle or axiom, known through intuition.
- Synthesis: Deductively reconstructing the problem based on axioms intuited in the analysis.
Methodical Doubt and the Search for a First Principle
Descartes begins by analyzing, using methodical doubt to search for the axiom of his problem—the first truth. From this, he will deduce the nature of our knowledge. Descartes uses doubt to eliminate anything not entirely certain. He employs three types of doubt:
- The fallacy of the senses
- The inability to distinguish waking from sleep
- The hypothesis of an evil genius deceiving us
By doubting everything, including mathematics and logic, Descartes eliminates all realities except the primary axiom: “I think, therefore I am.” This absolute truth, free from doubt, is discovered through intuition. Its criterion of certainty is that everything known with equal clarity and distinctness is true.
Synthesis and the Structure of Reality
In the next step, synthesis, Descartes establishes an absolute truth: the thinking substance (res cogitans). Immediately present to one’s thinking are ideas, classified into three groups:
- Adventitious ideas: Derived from external experience and thus discarded.
- Factitious ideas: Combinations of adventitious ideas, also rejected.
- Innate ideas: Not from outside but possessed within thought itself, including logical, mathematical, and physical principles, and the idea of God as infinite.
God and the World
Descartes demonstrates the existence of God and, simultaneously, the world. He uses the principle of causality and the ontological argument. Given the idea of God as infinite, Descartes argues that this idea must have a cause. He dismisses his own thinking as the cause since it is finite and imperfect. The cause of the infinite must be more real than its effect. Therefore, the cause of the idea of infinity is God. Using Anselm’s ontological argument, Descartes argues that God, a perfect being, must exist because without existence, God would not be perfect. The world’s existence is demonstrated because God, being good and true, would not deceive us into believing in a non-existent world. God guarantees a world of primary, quantifiable qualities.
The Three Substances
Descartes distinguishes three levels of reality:
- God as the infinite substance
- The self as a thinking substance
- The world of bodies as an extended substance
Each substance can be conceived independently. While Descartes initially defined substance as existing without needing anything else, he acknowledges this applies only to God. His metaphysics focuses on these three substances.
Mechanism and Anthropological Dualism
In Cartesian physics, influenced by Galileo, the focus shifts from final causes to efficient causes (how things work). The objective, primary qualities of bodies are mathematically quantifiable, while secondary qualities are subjective impressions. The universe is a perfectly designed machine created by God. Humans are composed of two distinct substances: thinking (mind) and extended (body). Descartes proposes the pineal gland as the point of interaction between these substances. Since the soul is independent of the body, Descartes concludes it is immortal.