Descartes’ Philosophy: Cogito, God, and Certainty
To understand Descartes’ philosophy, one must grasp a fundamental truth: doubting everything leads to the realization that there is someone who doubts, and therefore, a thinking intelligence exists. From this, Descartes concludes the existence of thought, famously stated in Latin as “Cogito, ergo sum” (I think, therefore I am), which he considers the first certainty. It is the only knowledge that can assert its own existence.
An analysis of this first certainty reveals that existence is recognized through thought (which no other knowledge can recognize its own existence), and that existence is a condition for the possibility of thought.
It’s important to recognize that this understanding occurs in terms of thought, conscience, and mind, rather than on the plane of physical reality.
The entirety of Descartes’ philosophy stems from this initial point.
This thought can be referred to as “I” or “soul,” because it is initially unknown if it is accompanied by a body. Therefore, this “I” is something immaterial, pure thought, a capacity unique to humans. Descartes’ thought does not concern itself with the physical hardware of the brain.
But why is this certainty clear and distinct? It is clear because it is understood accurately, and it is distinct because it is well-defined and not confused with other concepts.
Descartes interprets the notion of thought as mental contents, which is different from Plato’s concept of an “idea.” He distinguishes between the ideas themselves and the things they represent, and he identifies three levels of reality: the self (I), my thoughts, and external reality.
Regarding the characteristics of ideas, not all ideas are equal. There are three types:
- Adventitious Ideas: These are ideas derived from external sources. They do not, in themselves, prove the existence of the external world.
- Factitious Ideas: These are ideas that are the product of imagination, created by the individual.
- Innate Ideas: These ideas do not originate from external sources, nor are they created by the individual. They are potential ideas, present from birth, though not immediately known.
This line of reasoning leads to the problem of solipsism: the acceptance that only one’s own mind is sure to exist.
To escape solipsism, Descartes relies on innate ideas, as the other two types are either derived from the external world or created by the individual. Descartes focuses on two innate ideas: infinity and perfection.
From these innate ideas, Descartes attempts to prove God’s existence. He argues that God serves as the guarantee for the validity of adventitious ideas, ensuring the certainty of human knowledge.
Descartes cannot use St. Thomas Aquinas’ arguments for God’s existence because those arguments are based on empirical experience, and Descartes distrusts the senses.
These innate ideas, Descartes argues, can only originate from God, because they could not have been caused by the individual, who is finite and imperfect. They must have been placed within the individual by a being possessing those qualities, an infinite and perfect being. From this, Descartes demonstrates the existence of God. And from God’s existence, Descartes draws several conclusions:
- If God exists, then there is no evil genius deceiving us. Although the problem of why evil exists if God is good remains a question (a concern that preoccupied St. Augustine), it is not Descartes’ primary focus.
- Clear and distinct ideas are true, restoring confidence in reason. God guarantees the certainty of knowledge.
- With renewed trust in reason, one can investigate any area of knowledge and verify it using the proper method.