Descartes' Method: Doubt, the Self, God, and the World

Descartes: The Method

Descartes' problem was the worry about the merits of the many mistakes regarding knowledge. He recognized that over the centuries, many mistakes had been presented and defended as unquestionable truths. If human reason was a valuable and effective tool, why could science and the philosophy of science not advance? Descartes thought that a method had enabled him to find safety in knowledge, but philosophy lacked a proper method. The mathematical method introduced here gives human reason a definitive criterion of truth. According to Galileo, mathematics is seen as a rational science that brings order to the chaos of data. Descartes was convinced that, just as geometers could make things easier from the more complex without any human error, it could also be perfect for any area of knowledge with that method. He established the four fundamental rules of his method: intuition, analysis, synthesis, and enumeration.

The Doubt and the First Truth

According to Descartes, the most sensible thing to do is to question all knowledge and go for undoubted truths, hence the famous universal doubt:

• The uncertainty of sensory data (Descartes doubted all data originating in the senses; he doubted his hand, body, and all material reality).
• The errors of reasoning (Man often commits errors. A part of traditional knowledge is based on reason and its discursive power, but at the time of Descartes, that knowledge was confusing and uncertain).
• The difficulty in distinguishing sleep from waking (According to Descartes, all thoughts of waking can exist in dreams; we cannot really recognize them).
• The hypothesis of the evil genius (For his universal doubt, he supposed the existence of an evil genius that leads you to consider obvious things that are not).

But doubt is certainly a step toward finding the truth. When I doubt, and I think, the action implies the existence of a being that thinks (I think, therefore I am) "Cogito, ergo sum".

The Three Substances

The Thinking Self

Universal doubt leads us to an undeniable reality: the existence of a thinking self, a substance that thinks (a soul). Descartes thinks that he can doubt the existence of his body but cannot doubt the existence of subjectivity. Subjectivity is the set of thoughts and ideas that influence me. I do not have the security that these subjective representations correspond to facts in the external world, but they come from the senses, and Descartes decides to doubt them.

Ideas of Descartes

• Adventitious or acquired (ideas from outside, of sensible experience, my perception of the world, or teaching).
• Artificial (Ideas that we invent or manufacture ourselves).
• Natural (ideas that emerge from the very power of thinking. These are ideas that our mind grasps and has the power to accept without changing anything).

God

Consider the thinking self, which is not perfect. The thinking self has the idea of perfection. If we are aware of our imperfect nature, it is because we know what perfect nature is. The idea of perfection is innate in us; it is the idea of a perfect God. Descartes thinks that the idea of perfection cannot be outside of us (imperfect beings); it must have been left by a divine reality that entered our minds. God overcomes my subjectivity. Outside of me, there is another reality, a being that cannot allow my clear and distinct ideas to be a deception. God becomes a guarantee of knowledge.

The World

My self is fully aware of the difference between the idea of the thinking self and the idea of the extended body. I cannot doubt the thinking self, but I can doubt the body. In addition to the thinking substance, there is another type of finite and created substance: the bodies, all attributed to the field of extension. This is the third substance of Cartesian metaphysics. The thinking self and matter belong to different orders; thought has nothing to do with material reality.