Rene Descartes: Philosophy and the Foundations of Modern Thought
Rationalism: Faith and Reason
Rationalism addresses the tension between faith and reason. According to St. Augustine, they were completely united: faith is necessary to achieve truth, which is God. We can define Rationalism as the self-sufficiency of reason as a source of knowledge. Rationalism is the philosophical doctrine that explains:
- Origin of knowledge:
- Empiricism: knowledge comes from the senses.
- Rationalism: valid and true knowledge about reality comes from reason.
- The science of ideas and principles of science come from:
- Empiricism: knowledge comes from sensitive experience.
- Rationalism: innate ideas are in the understanding, possessed independently of any possible experience.
We have full trust in rational knowledge, the only valid knowledge that comes from reason. The senses deceive us and lead us to error. Sensitive knowledge is limited: it cannot be universal. Descartes affirms the existence of innate ideas in the mind that are independent of experience.
Descartes’ Method: Doubt and Certainty
The first step in Descartes’ philosophy was the disappointment in the studies he had undertaken. It was necessary for a truly unique philosophy, namely a rating of life outside the chancellor, to be set in the human method. Descartes looked to mathematics; if it is a way of knowing, there is progress, pluralism does not fit, and solutions are universally accepted. This method consists of intuitions and deductions. Intuition is the search for evident truths, indubitable, that cannot be denied in any way, such as 2 + 2 = 4. These are axioms that are not demonstrable. Deduction is the necessary conclusion derived from other things known with certainty.
The starting point of Descartes is doubt. He wants to distinguish truth from falsehood and thus power the solid foundation of certainty. Doubt can be universal (everything can be doubted), methodical (it is a constructive purpose and aims to achieve a truly firm truth that cannot be doubted), and theoretical (rethinking philosophy from the foundations).
But what does Descartes doubt? Descartes doubts everything that surrounds him. He doubts the senses, the outside world, his own reasoning, and even himself.
With doubt, Descartes sweeps away all reviews and leaves in abeyance any certainty, all but the truths of faith and moral standards.
Cogito, Ergo Sum: The Foundation of Knowledge
The truth of the Cogito is the first in the order of knowledge. It is the truth as soon as the gathering of faith you can, from this basis, doubt methodically. It is the basic axiom that develops philosophy as a whole system of knowledge, absolutely fundamental. The Cogito serves to prepare our minds and in such a way to strip it so that it can perceive immediately so clear and true saying. In “Cogito, ergo sum” there are two clear items: “I think” (not a pure mental act, but a set of things) and “I exist” (Descartes starts from his own interiority, the thinking self discovers itself, and reaches existence).
Descartes’ Classification of Ideas
- Adventitious ideas: those that seem to come from outside our experience.
- Factitious ideas: those that come from our imagination and will.
- Innate ideas: the understanding possesses these ideas by its very nature. This is the fundamental affirmation of rationalism.
From the Cogito, Descartes deduced the substance of God as infinite. He formulates three arguments to demonstrate the existence of God:
- The idea of infinity, being more perfect than myself, can only proceed from an infinite being; therefore, God exists.
- From the fact that I exist and possess the idea of a perfect being, the existence of God is clearly inferred.
- Descartes says it is impossible to conceive of God without His existence, that is, to conceive of an extremely perfect being without one of the perfections.
Anthropological Dualism: Mind and Body
The “I” that thinks is a reality distinct from the body, and the body must be understood as matter constituted by extension, space. The soul must be understood as spirit, formed by thought, as something completely distinct from the body. The coordination of these two realities is carried out by the pineal gland, where the soul feels especially its effectiveness in all parts of the body.
The problem of dualism is completely related to freedom. It is necessary to defend the distinct nature of the soul and body and its total independence to subtract the soul from compliance with the necessary laws of the universe.
Relationship Between Descartes and Other Authors
Descartes is usually considered the initiator of modern philosophy, due to the fact that he definitively abandoned the naive vision of reality that had dominated Greek philosophy, from scholasticism to the knowledge of ideas and not of things. Just as Platonic ideas were unique and immutable realities separate from sensitive things, with modern ideas, they are conceived as an object of thought.
The authenticity of the ideal world and the consequent falsity of the sensitive world did not constitute a problem. With Descartes, the problem appears when trying to relate thought to external reality and subjective reality.
Spinoza’s philosophy re-elaborates the concept of Cartesian substance and applies it only to God. According to this, thought and extension are two of the attributes that we know among the infinite attributes of the only substance.
All three authors share the same project of the unification of science and the importance of the mathematical method.