Rationalism and Descartes’ Philosophy: A Comprehensive Overview
The Problem of Knowledge: Epistemology
Descartes and Rationalism
René Descartes, a prominent figure in 17th-century philosophy, is considered the founder of modern philosophy and a leading thinker of Rationalism. Rationalism is a philosophical school of thought that emphasizes reason, as opposed to the senses, as the sole source of true knowledge.
Descartes’ Method for Certain Knowledge
For Descartes, the primary objective was to establish a foundation of sure and certain knowledge—a theory that could be considered true beyond any doubt. To achieve this, he prioritized the development of a method for reasoning, a guide for philosophical inquiry. This method needed to be compatible with human reason to be effective. Descartes began by analyzing the act of reasoning itself and concluded that human reason, which is universal, possesses two distinct types of knowledge:
- Intuition or Natural Light: This refers to the immediate apprehension of simple ideas that arise directly from reason. These ideas are clear and distinct, their truth self-evident and undeniable.
- Deduction: This involves understanding a series of interconnected simple ideas, insights, and connections that reason uncovers to arrive at complex truths, propositions, or laws.
According to Descartes, these two modes of knowledge necessitate a specific method and process for acquiring knowledge. This process involves two key steps:
- Analysis: Complex ideas are broken down into simpler, clearer components that can be grasped through intuition.
- Synthesis: Through deduction, a conclusion is reached that explains the complex idea, and laws are formulated to elucidate it.
Methodical Doubt and the Search for an Indubitable Truth
Descartes employed this method to uncover an indubitable truth through analysis and subsequently build upon it through synthesis to arrive at a certain metaphysical foundation. To discover this self-evident truth, he utilized the method of methodical doubt. This involved several stages:
- First Doubt: Descartes questioned the reliability of knowledge derived from the senses, as they can be deceptive.
- Second Doubt: He doubted the existence of extra-mental reality, as it is impossible to definitively distinguish between wakefulness and dreaming.
- Third Doubt: Descartes even doubted knowledge originating from reason itself, including ideas of reason and reasoning processes. He entertained the possibility of an evil genius who systematically deceives us into believing falsehoods.
However, Descartes argued that even in the midst of doubt, one cannot doubt the act of doubting itself. Since doubting is a form of thinking, we cannot doubt that we are thinking, and therefore, we must exist. This led him to the first indubitable truth: Cogito, ergo sum—I think, therefore I am. This affirms the existence of a thinking substance (the cogito) as the first self-evident principle.
Building a Synthesis from the Cogito
From this foundation, Descartes sought to construct a synthesis that would lead to certain knowledge. He examined the cogito’s capacity to think hypothetically about ideas, which he categorized into three types:
- Adventitious Ideas: These appear to originate from external sources.
- Factitious Ideas: These are constructed by the mind from other ideas.
- Innate Ideas: These are inherent to reason itself and are neither adventitious nor factitious.
The Problem of God: Metaphysics
The Idea of Infinity and the Existence of God
Among the innate ideas, Descartes identified the idea of Infinity, which he equated with the idea of God. He argued that the idea of the Infinite (God) present in our minds is neither adventitious nor factitious; therefore, it must be innate. Descartes then applied the principle of causality to establish God’s existence. Since the innate idea of Infinity could not have been caused by a finite being (as there must be a proportionate relationship between cause and effect), it must have been caused by an infinite being. Thus, he concluded that God exists.
Descartes characterized God as the infinite substance, possessing attributes of infinity, omniscience, perfection, and goodness. This affirmation of God’s existence served as a guarantee, a foundation, for the reliability of our ideas about the external world. God’s goodness ensures that these ideas correspond to an extra-mental reality, as God would not deceive us.
The Problem of Reality: Metaphysics
Three Substances: Cogito, God, and Extended Reality
Descartes posited the existence of three distinct substances:
- Cogito (Thinking Substance): The thinking self.
- God (Infinite Substance): The ultimate and independent being.
- External Reality (Extended Substance): The physical world.
Descartes defined substance as anything that exists independently of any other being. In the strictest sense, only God qualifies as a substance because God alone does not require a cause beyond itself to exist. However, since the extended substance (external reality) and the thinking substance (the cogito) are independent of each other (as the soul can exist without the body and reality without the self), they are also considered substances.
The Problem of Man: Anthropology
Dualism of Soul and Body
Descartes viewed the human being as a thinking substance (the cogito), independent of the extended substance (in this case, the body). The body, like any physical entity, operates as a machine (as asserted by mechanism) and lacks free will. However, the soul (cogito), which is immortal, possesses free will and should govern the body. This establishes a dualism in which the soul and body are engaged in a constant struggle.
The interaction between these two substances occurs through the pineal gland, which allows the soul to control the body.
The Problem of Moral: Ethics
Freedom, Perfection, and Happiness
Descartes believed that the development of the soul’s perfection leads to happiness. He equated the development of the soul’s perfection with the development of freedom. Freedom is achieved through the control and guidance of desires and passions that arise from the body. This occurs when the individual is not dominated by the extended substance but instead governs through their cogito.
Freedom, in this context, is understood as the realization of the proposals of the understanding—what is good and true—by the will.