Descartes’ Philosophy and Scientific Revolution
Descartes’ Method and the Pursuit of Certain Knowledge
René Descartes aimed to establish a foundation of certain knowledge, beyond reasonable doubt. He believed that all knowledge should be governed by the axiomatic principles of mathematics. In his Discourse on Method, he outlined four key rules:
- Rule of Evidence: Accept only what appears clearly and distinctly to the mind.
- Rule of Analysis: Divide complex problems into simpler parts.
- Rule of Synthesis: Reconstruct knowledge from these simpler parts.
- Rule of Enumeration: Review thoroughly to ensure completeness.
Methodic Doubt and the Cogito
Descartes employed methodical doubt, not as pure skepticism, but as a tool to arrive at truth. He questioned the reliability of the senses and even the possibility of a deceiving God. Amidst this doubt, he discovered the undeniable truth of his own existence: Cogito, ergo sum (I think, therefore I am).
Substance and its Attributes
Descartes defined substance as something that exists independently. He identified God as the infinite substance and extended the term to res cogitans (thinking substance) and res extensa (extended substance). Each substance has an attribute (its essence) and modes (the ways the essence appears). The res cogitans has thought as its attribute, while the res extensa, corresponding to the physical world, has extension.
The Problem of Solipsism
Methodic doubt raises the issue of subjective solipsism—the difficulty of proving the existence of other minds or the external world. Descartes attempted to address this by suggesting the pineal gland as the point of interaction between mind and body.
The Necessary Existence of God
Descartes categorized ideas as innate, adventitious, or factitious. He argued that the idea of God as an infinite substance is innate. Since humans are finite beings, they could not have produced this idea, therefore, God must exist as its source. This guarantees the truth of clear and distinct ideas and affirms the reality of the external world.
Descartes’ Scientific Ideal and a New Ontology
Descartes sought to replace Aristotelian philosophy and science with a comprehensive system of knowledge. He envisioned a mechanistic universe where nature is res extensa, characterized by matter and motion.
Matter and Motion
Descartes identified matter with three-dimensional space, a plenum excluding the void. Matter exists as divisible particles with figure and extension. Motion, set in motion by God, remains constant in quantity.
Laws of Motion
Descartes formulated laws of motion, including the law of inertia (a body remains in its state of rest or uniform motion unless acted upon by a force), the principle of rectilinear motion, and the law of conservation of momentum in collisions.
Cosmology of Vortices
Descartes proposed a universe composed of vortices, or whirlpools of matter, around central stars. This heliocentric system operates like a clockwork mechanism, set in motion by God but continuing autonomously under the laws of motion.