Substance, God's Existence, and the Human Soul: A Cartesian View

Concept and Types of Substance

Three realms have discovered reality: God, or the infinite and true; I, or the thinking thing; and material things. Infinite substance, thoughtful and extensive. "Substance" is only applicable to God, but it can be applied to other beings that we perceive clearly and distinctly and that do not need anything else, except God, to exist. How do we perceive substance? By perceiving attributes, qualities of the substance that cannot exist by themselves, and each substance has its own essence. Res cogitans (thinking substance): thought; Res extensa (extended substance): extension.

Demonstration of the Existence of God

Causation argument applied to the idea of Infinite God:

1. Theory of the objective reality of ideas.
2. From nothing, nothing comes; there can be no more reality in the effect than in the cause.

The idea of an infinite being must have been caused by a being proportional to the idea, meaning that an infinite being exists.

Argument of God as the cause of my being: In my mind, there is an idea of infinite perfection; my reality or formal act should be proportional to the idea. I cannot be the cause of that idea; therefore, God exists.

The ontological argument: The idea of a perfect being includes existence.

God exists and is perfect, infinite, eternal, immutable, absolute power, and a benevolent, not a malignant, genius. In the first method, clear and distinct ideas are true if we do not doubt them. If God has willed it, and if we make mistakes, it is because we loved and took clear, imperfect, and confused ideas as true.

God created the universe of inert matter and has given it motion. The quantity of motion in matter is constant and unchanging; God is immutable and requires no further intervention in his extensive creation. Matter is infinitely divisible, giving rise to all kinds of beings. There is no indivisible matter. Shock and friction create filings. There is no void; motion occurs through contact.

Anthropological Dualism

The human being is composed of two substances: thinking and extended matter, independent and mutually irreducible, yet closely united as body and soul. The soul is a thinking substance, totally independent of the body; despite the union, the soul can exist without the body. This serves to shield compliance with the necessary laws of the mechanistic universe, except to allow for freedom. The body is subject to material laws, has no freedom, and is a simple machine that answers to the laws of physics. Problem: This is an even more radical separation than two distinct substances, yet we are aware of the close relationship between them. To explain this relationship, the problem uses a physiological explanation: in the center, the lower part of the brain, is the pineal gland, where the soul resides, serving as the point of interaction between soul and body.

Passions of the Soul

Passions are perceptions, feelings, or emotions that are given to us and affect the soul, originating in the body. They are involuntary, meaning they do not depend on the rational soul, and irrational, as they are inconsistent with the dictates of reason. The soul tries to control and direct the passions. Reason is tasked with providing knowledge and judgments so that the will can adequately lead the activities of life; liberty is involved.

Two Functions of the Soul

Understanding: the ability to think, to have intuitions of clear and distinct truths. Will: the power to affirm or deny; the will derives from freedom. From this derives the theory of error: asserting by precipitation or denying by prevention. The possibility of error derives from freedom. Freedom consists ultimately in the will directly choosing what understanding clearly and distinctly presents as good and true.