Descartes' Philosophy: Rationalism, Metaphysics, and Dualism

Descartes' Philosophy: Rationalism and the Cartesian Method

Rationalism

Descartes was the founder of rationalism, which posits that reason is the superior source of knowledge and provides us with truths.

Cartesian Method

Descartes' conception advocated for the unity of knowledge, meaning all knowledge is based on reason. However, it is necessary to understand its structure to achieve it. To do this, he took mathematics as a model and used the appropriate method. Reason is based on intuition, which enables simple concepts without error, and deduction, which is deriving knowledge from several intuitions. The discourse of the method consists of:

• **Evidence:** Nothing can be taken as true without knowing what it is.
• **Analysis:** Divide complex problems into simpler parts.
• **Synthesis:** Order thoughts from the simplest to the most complex.
• **Enumeration:** Review all parts to ensure correctness.

With this method, Descartes believed that any problem could be solved through thought and reason.

The Existence of the Self

For Descartes, the first objective was to find a first evident truth. To achieve this, he employed "methodical doubt," which means doubting everything to find the real thing. There are different levels of doubt:

• **Empirical knowledge:** The senses often deceive us.
• **Rational knowledge:** Reason can also fail.
• **The impossibility of distinguishing between dreams and wakefulness:** Doubting the existence of things and the world.
• **The hypothesis of the evil genius:** A hypothetical genius controlling us, leading us into error.

This might seem to lead to radical skepticism, but there is one thing we cannot doubt: our own existence. Since we doubt, we think, and if we think, we exist. Therefore: "I think, therefore I am."

Ideas

Having found the first truth, Descartes tried to reach other truths to escape solipsism. Thinking is embodied in ideas, which are psychic evidence. These are classified according to their origin:

• **Adventitious:** Coming from outside, based on external experience.
• **Factitious:** Created by the imagination based on empirical experience.
• **Innate:** Not learned, part of understanding, and the only truly evident ones.

Only innate ideas allow us to escape solipsism and justify the existence of God.

Descartes' Metaphysics and Anthropology

New Science and Mechanistic Interpretation of the Universe

In Descartes' time, scientific developments led to a new image of the universe, a mechanistic vision that explained how physical phenomena occur but not why. Metaphysics deals with the why, not reason. In other words, mechanism addresses efficient causes, not final causes. Descartes mixed science with metaphysics and religion to give a mechanistic vision of nature and explain the existence of God. The first cause of motion is God, who produces the movement of matter, resulting in various substances.

Theory of Substance

Descartes defined substance as that which exists and does not need anything else to exist. Thinking beings are finite, and God is the ultimate substance. In other words, bodies are derived from God. God is the first ontologically infinite substance, having created the rest. The soul is thought, the essential attribute of the soul. Bodies are the third order of reality, and their essential attribute is extension.

Existence of God

The idea of God is innate. Descartes proved its existence by stating, "The idea of God has more objective reality than the rest. Since God is the most perfect, He cannot come from something less perfect, like man. Therefore, the idea of God comes from God Himself, and thus, God exists." The idea of God is so inherent in our nature that its objective reality could not have originated from us. Analyzing His idea, He is the creator, omnipotent, and perfect, so these features demonstrate the existence of the world.

Cartesian Anthropology

Descartes defended ontological dualism, meaning the independent existence of body and soul. The soul is an eternal spiritual substance whose essential attribute is thought, possessing two qualities: understanding and freedom. The body is a finite, non-eternal material substance whose essential attribute is extension. For Descartes, the body is insensitive, acting according to the laws of mechanics. Passions are feelings that affect the soul and must be controlled by reason. Thus, freedom underlies the ability to choose the good by subjecting it to understanding, which discovers the real order preferentially through the deductive mathematical method.