Descartes’ Philosophy: Doubt, Substances, and Ethics
Methodical Doubt
To achieve certain knowledge and eliminate error, Descartes employed methodical doubt. This involved questioning all existing beliefs. His method dictates challenging every idea, accepting nothing as true unless it’s beyond doubt. This applies specifically to scientific and philosophical knowledge.
Reasons to Doubt
- False Testimony of the Senses: Our senses can deceive us, leading to errors in perception.
- Distinguishing Wakefulness and Sleep: It’s difficult to differentiate between waking and dreaming states, although mathematical truths hold in both.
- The Evil Genius Hypothesis: A powerful, malevolent being might deceive us, even about mathematical truths.
Descartes’ doubt wasn’t skeptical; it aimed to find absolute truth. Doubt itself leads to the first certainty: I think, therefore I am.
The Three Substances
Descartes defines substance as something that exists independently. Strictly applied to God, it also extends to created realities needing no other created elements to exist. We perceive a substance’s attributes, not the substance itself. Each substance has a defining attribute. Substances also have modes, which are changes in their presentation.
Besides God (res divina) with the attribute of perfection/infinity, Descartes identifies two other substances:
- I (res cogitans): Characterized by thought.
- Bodies (res extensa): Characterized by extension.
Man
Humans have a dual nature, composed of two substances: extended substance (body) and thinking substance (soul). These are independent, with only the soul’s existence being clear. Descartes affirms the soul’s immortality, as its existence doesn’t depend on the body. Physical laws govern the body, not the soul. Descartes believed the soul and body interact through the pineal gland.
Ethics
Descartes distinguishes between actions and passions. Actions are will-dependent decisions and behaviors. Passions, like feelings and emotions, are involuntary bodily responses, not always aligned with reason. Reason reveals the good, and the will should follow it. Passions, arising from bodily forces, can be controlled by reason through the will. Descartes’ ethics emphasizes submitting the will to understanding.