Descartes’ Substance, Method, and Ideas: A Philosophical Analysis

Posted on Jan 11, 2025 in Philosophy and ethics

Descartes’ Concept of Substance

First Definition: Descartes used ‘substance’ and ‘thing’ as synonyms. A substance is a concrete existing entity that is independent for its existence. It does not need anything else to exist. Only God is a true substance, as creatures depend on God for their existence. However, the concept of substance applies differently to God and creatures.

  • Infinite Substance: God, who is absolutely self-defined.
  • Finite Substances: Souls and bodies, which depend on God but not on other finite substances.

Second Definition: Each substance has an attribute, which is its essence. The soul’s attribute is thought, and the body’s attribute is extension.

Third Definition: Modes are the various ways in which substances exist. For example, a body (substance) has extension (attribute) and a specific figure (mode).

Aristotle’s Theory of Knowledge

Aristotle’s theory of knowledge is empirical. Our senses provide data about the material world, which is essential for knowledge. Aristotle believed that reality is intelligible. He argued that all things are composed of matter and form, allowing for universal knowledge. Unlike Plato, Aristotle valued the senses as the starting point of knowledge, which is then continued by thinking. Senses are a potential for knowledge, updated by the sensitive subject.

Descartes’ Method

Four Phases:

  1. Evidence: Accept only what is evident and indubitable as true.
  2. Analysis: Break down complex problems into simpler parts until you reach evident truths.
  3. Synthesis: Reconstruct knowledge by logically deducing consequences from evident truths.
  4. Enumeration: Review the analysis and synthesis to ensure no steps were missed.

Methodical Doubt

Descartes’ method begins with doubt, questioning everything:

  • Reliability of the Senses: Senses can deceive us, so they cannot be a source of absolute truth.
  • Existence of the World: The world might be an illusion or a dream.
  • Reliability of Mathematics: Even mathematical truths could be manipulated by an evil genius.

Overcoming Doubt

Descartes overcomes doubt with the statement, “I think, therefore I am.” The act of thinking proves one’s existence. The soul is a thinking thing, distinct from the body, which could be an illusion. The ‘I’ that thinks is a subject, and even if thoughts are wrong, the thinking subject exists.

Descartes’ Theory of Ideas

Ideas are produced by a thinking subject. They are mental products, and everyone has their own ideas. Descartes classifies ideas based on their origin:

  • Adventitious Ideas: Derived from experience.
  • Factitious Ideas: Created by the imagination.
  • Innate Ideas: Inherent to the mind, such as the idea of God.

The idea of God is innate, representing a perfect and infinite being. It is not factitious because we are imperfect and finite.