Descartes' Philosophy: Doubt, Mind, God, and Reality

Descartes' Methodic Doubt and the Cogito

This text introduces the doubts René Descartes systematically applied to everything surrounding him. He questioned everything derived from our senses, the pronouncements of the wise, and even mathematical certainties. Descartes initially suspected that everything he had ever believed might be deceptive. He pondered: if God is infinitely good and powerful, why would He allow us to be deceived? Or perhaps, he speculated, we are deceived by some malicious entity or for some unknown reason.

However, Descartes explained that one thing cannot be doubted: the act of thinking itself. He famously concluded, "Cogito ergo sum" – if he thinks, then he must exist. From this certainty arises the correspondence between thought and reality; Descartes concluded that if the rational soul exists, then reality, as perceived through clear and distinct ideas, must also have a foundation.

He questioned whether bodies external to his mind truly exist or are merely imaginary constructs. He also affirmed the existence of God, characterized as infinitely good, infinitely powerful, infinitely wise, and the creator of all things, including ourselves.

Cartesian Substances: Mind, Matter, and God

Extension (Res Extensa)

Extension in length, width, and depth is the principal attribute by which we know material substance; it constitutes its nature and essence, and all other properties depend on it. Features attributed to bodies, such as shape and movement, presuppose extension. Descartes presented these ideas with a geometric or mathematical conception of physical reality, considering only those physical properties that can be described mathematically as truly real. For Descartes, animals were purely extended things (machines), while humans possess both extension and thought.

Thought (Res Cogitans)

Thought is the essential attribute of the thinking substance (Res Cogitans). This is a created substance. For the first time in modern European philosophy, Descartes centered philosophy on self-awareness – the thinking self recognizing its own existence as a primary certainty, foundational even before proving God's existence.

God (Res Infinita)

God represents the divine or infinite substance (Res Infinita). Unlike mind and matter, this substance is uncreated and possesses the attribute of infinity. Descartes invoked God as the ultimate guarantor of the reality of the world external to the self. Since deception is contrary to God's perfect nature, we can trust that the clear and distinct perceptions of our senses, and especially our reason, correspond to an actual reality. Therefore, the material world is real.

Descartes: Life, Times, and Philosophical Context

Biography and Era

René Descartes (1596-1650) was a pivotal philosopher of the seventeenth century. Educated in Scholastic philosophy, he went on to build his own influential philosophical system. He was also a renowned mathematician and scientist. Descartes lived during a period of significant transformation in Europe (often associated with the later Renaissance and the beginning of the Modern era), marked by profound social, cultural, and political changes.

Historical Context

Key aspects of his time include:

• Social and Economic Changes: The rise of the bourgeoisie as a new social class, gradually displacing the political power of the traditional nobility and clergy.
• Political Developments: The consolidation of new nation-states and the expansion of colonial empires.

Intellectual Climate and Rationalism

The era's ideology was characterized by a growing confidence in human reason to explain the world and drive the advancement of science and technology. Philosophers, notably Descartes, sought a unified system of knowledge grounded in a universal scientific method, often inspired by mathematics. Philosophy began to diverge into two major currents:

• Rationalism: Championed by Descartes, Spinoza, and Leibniz. Rationalists sought to create deductive philosophical systems modeled on mathematics. They emphasized reason as the primary source of valid knowledge and believed in the existence of innate ideas.
• Empiricism: Focused more on experimental sciences and based its claims to truth on what could be empirically verified.

Modern philosophy, significantly shaped by Descartes, shifted focus to the relationship between the knowing subject and the object known.