Key Concepts in René Descartes’ Philosophy
René Descartes: Core Philosophical Concepts
René Descartes, born in France in the sixteenth century, studied with the Jesuits and was familiar with atomistic philosophy (Scholasticism).
Descartes’ Method of Rules
Following the collapse of Aristotelian-Thomistic philosophy, Descartes’ fundamental objective was to find a method with clear rules to ensure concrete reasoning and the reconstruction of all human knowledge. His method is based on four rules:
- Rule of Evidence: To accept only what is clear and distinct, derived from intuition or intellectual vision of a truth, or through deduction.
- Rule of Analysis: To reduce complex problems to their simplest, intuitively knowable elements.
- Rule of Synthesis: To begin with simple elements and progressively build up to complex arguments.
- Rule of Enumeration/Review: To review all previous steps thoroughly to ensure no flaws in reasoning have been overlooked.
Methodical Doubt and the Cogito
Descartes applied methodical doubt to metaphysics to ascertain what could be known as truly certain, thereby establishing a firm foundation for knowledge. This process involves systematically questioning all our beliefs to determine their certainty and security. It proceeds through several levels:
- Distrust of Sensory Knowledge: Our senses can deceive us; therefore, sensory information cannot be fully trusted.
- Confusion Between Sleep and Wakefulness: Dreams can be so vivid that they are indistinguishable from reality, leading to the possibility that our entire life could be a dream.
- The Deceiving God Hypothesis: Even mathematical truths might be questionable if we consider the possibility that a powerful, deceptive God created us in such a way that we are inherently mistaken about everything, even seemingly certain facts.
- The Evil Genius Hypothesis: Even if God is benevolent and would not deceive us, there could be an evil genius or demon of supreme power and cunning who constantly works to deceive us.
Although methodical doubt initially casts doubt on all our knowledge, including mathematics, Descartes found an undeniable truth within the act of doubting itself: “I doubt, therefore I think; I think, therefore I am” (Cogito, ergo sum). The very act of doubting proves the existence of a thinking self.
Demonstrations of God’s Existence
Descartes defines humans as thinking substances containing ideas, volitions (wishes), and judgments. While volitions and judgments can lead to error, ideas are divided into three classes:
- Adventitious Ideas: These come from external objects through the senses (e.g., the idea of a tree).
- Factitious Ideas: These are created by our imagination (e.g., the idea of a unicorn).
- Innate Ideas: These are natural to us and are present from birth (e.g., the idea of God, or mathematical axioms).
Descartes argues that the idea of an infinitely perfect being (God) cannot originate from us, because as finite and imperfect beings, we cannot conceive of something greater than ourselves. Therefore, this idea must have been implanted in us by an infinite and perfect being. Thus, God exists.
Descartes also presented two other arguments for God’s existence:
The Ontological Argument
Since we possess the idea of an infinitely perfect being, and existence is a perfection, it necessarily follows that such a being must exist. A perfect being that lacked existence would be less than perfect, which is a contradiction.
The Cosmological Argument (from Contingency)
If I possessed all perfections, I would be self-sufficient and would not need to be created. However, we know that we are finite and contingent beings, meaning we did not create ourselves. Therefore, we must have been brought into existence by another being. This chain of contingent beings cannot extend infinitely, as there must be a first cause or a necessary being that brought everything into existence and sustains it. This necessary being is God.
Descartes’ Anthropology: Mind-Body Dualism
Descartes’ anthropology is dualistic, positing a distinct soul (an immortal, thinking substance) and body (a material, extended substance). The body is viewed as a complex machine. The problem of how the immaterial soul interacts with the material body was a significant challenge for Descartes, which he attempted to resolve by proposing the pineal gland in the brain as the primary point of interaction between the two substances.