Descartes’ Foundational Philosophy: Cogito and God
Topics
Item 1: The Cogito and the Criterion of Certainty
In this issue, we explore the constructive part of Cartesian thought, focusing on rebuilding knowledge on solid foundations. The cogito and methodical doubt are crucial phases in this task.
Descartes argued that philosophy and science were in crisis. He proposed that the solution lies in reason, the innate human ability to judge and distinguish truth from falsehood. However, if all reason is equal, why are there differing views? Descartes sought to find the correct method for using reason.
The proper method involves two tasks: setting aside tradition to allow reason to manifest freely, and analyzing reason to determine its method. Reason operates through intuition and deduction. Intuition is the immediate grasp of clear and distinct ideas. Deduction connects intuited simple natures to form composite ones. Intuition is fundamental, so understanding how to intuit an idea is essential. An idea is intuited when it is clear, distinct, and well-known.
Descartes established rules to distinguish good reasoning. The first is evidence: accept only what is known with certainty. The second is analysis: break down difficulties to enable intuition. The third is synthesis: move from simple to complex ideas. Finally, listing ensures completeness.
Descartes applied methodical doubt, rejecting anything not clearly evident. This skepticism aims to find an indubitable truth. Doubt operates on three levels: sensory knowledge, the external world, and rational knowledge (using the evil genius metaphor).
Extreme doubt leads to the cogito: “I think, therefore I am.” This is the foundational truth.
The cogito establishes the criterion of certainty: anything thought clearly and distinctly is true. However, the evil genius hypothesis challenges this. To overcome it, Descartes demonstrates God’s existence.
Item 2: Evidence of God’s Existence
Descartes argues for God’s existence to validate the criterion of certainty. He rejects theological realism, favoring an a priori demonstration, similar to St. Anselm’s argument.
Descartes discusses the origin of ideas: innate, adventitious, or factitious. Ideas represent accidents, finite things, or infinite substances (God).
The first proof uses the principle of causality: there must be as much reality in the cause as in the effect. The idea of God as an infinite substance can only originate from God.
The second proof reformulates St. Anselm’s argument. The idea of God includes all perfections, and existence is a perfection, so God exists. Objections are addressed: we distinguish essence and existence in other things, but not in God.
God’s existence guarantees the criterion of certainty, overcoming solipsism and validating science. A perfect God cannot be deceptive, eliminating the evil genius. Errors arise from misusing our judgment.