Rene Descartes and the Substantive Structure of Nature, What is Substance?June 27, 2021
Descartes defined substance as “something that needs nothing but itself in order to exist”. However, this definition really fits the substance of God, which he describes as eternal substance. Because the substance of God owes its existence to itself alone, it does not need the help and contribution of anything else.
In other words, God exists by himself, eternally. Everything outside of God was created by his will and by him. However, since God is outside of the universe he created, we can leave that aside and state that in this universe, which is God’s creation, two substances with different structures, also created by God, prevail. In terms of the universe we live in, these substances formed the main subject of Descartes’ study.
These two substances do not need each other in order to exist or to continue their existence, and they are separate from each other. The only thing they have in common is that they are finite substances according to God because they were created by God, and they are equal as substances.
According to Descartes, “substance is that which needs nothing but itself to exist”.
These substances are “spirit-mind” and “matter” substances, as we have already become acquainted with largely because of what has been said above. They bring themselves into existence by their essential qualities: The essential nature of the spirit substance is to think, to constantly produce thoughts, ideas. In other words, consciousness is to reveal acts.
Since it is convenient for Descartes to express the substance with its essence, Descartes calls this substance “the thing that thinks” (res cogitans). The essence of the substance of matter is to be extended. For this reason, Descartes calls this substance the “extended thing” (res extensa). The essential qualities of substances are reserved for them; exists only in themselves, it can never be found in the other substance. This determination has made these two substances ruling in the universe irreconcilable with each other: Thinking substance is not extended, and extended substance is incapable of thinking.
According to Descartes, God is infinite substance, and besides, there are two finite substances, spirit and matter. The essence of spirit substance is to think, and the essence of matter substance is to occupy space.
All other predicates of substances are determined by these essential qualities. However, without the essence of substance, substance could not gain existence; therefore these essential predicates cannot be separated from substance. For example, although thinking is indispensable for the soul, the different variants of thinking call each other.
Some important secondary predicates of the spirit substance on the basis of thinking are mental acts such as perceiving, remembering, imagining, doubting, reasoning, drawing conclusions, willing, feeling, and their products. Since the primary, the essential predicate or quality, determines the substance, the soul or mind is constantly thinking; According to this, the individual thinks in deep sleep and in a state of unconsciousness or coma or even in the womb, because if he did not think, his existence as a spirit substance would disappear. Undoubtedly, this point has always been the subject of debate during and after Descartes’ time.
It was stated above that the essential quality of matter-body substance is extension: According to this, material substances cannot exist without extension; space is the essential quality of material substances, it is indispensable. As Descartes says, “Therefore, in length, breadth, and depth, spatiality forms the nature of substance,” attributes such as form, size, dimensions, and mobility are the primary predicates of the object. They are necessarily and objectively present in corporeal substance; material substance cannot be without extension, and space cannot be without them; These are the qualities that make the object really exist. Yet they are mutable or mutable states of space.
But there are also qualities such as color, sound, taste, warmth and coldness that we perceive in corporeal substances. Do these also exist objectively, like spatial changes in corporeal substances, or do they not? Descartes calls these secondary qualities. Therefore, it is obvious that they differ from the first. According to Descartes, they do not actually take place objectively in corporeal substances. They are the situations that occur in the presence of the subject who perceives them as a result of the ability of objects to move our nerves in different ways. To put it briefly, external things, moving extended things, cause in us sensations such as color, sound, taste, smell. Therefore, according to Descartes, corporeal substances are not exactly as they appear.
As a result, Descartes states that the perception of objects through the senses is in many cases rather blurry and obscure. Space is what we clearly and distinctly perceive as belonging to the essence or nature of corporeal substance. But our ideas of colors and sounds are not clear and distinct. According to the conclusion from what has been said, what has been said about the truth conditions of the sense-based information of external beings, one of the types of knowledge we have evaluated above by Descartes, is better justified at this stage.