Rationalism: Core Principles and Descartes’ Modern Philosophy
Rationalism: General Characteristics
Rationalism is the philosophical theory that inaugurates modernity. Seventeenth-century philosophical rationalism essentially belongs to Descartes. Rationalism can be broadly defined as the philosophy that defends reason as the primary source of knowledge. A rationalist philosopher typically defends these basic theses:
- Confidence in reason is a basic element inherited from the Renaissance. Reason is objective, universal, and necessary, unlike faith and tradition. Reason is the foundation of science and the instrument with which humanity can dominate the world.
- Devaluation of Sensory Knowledge: Rationalists believe that the senses can deceive us.
- Innatism: This is the claim that human reason possesses innate ideas, which are present from birth and evolve with us. They are universal and form the foundation of all reasoning. Innate ideas are central to Descartes:
- Cogito ergo sum (I think, therefore I am)
- Idea of God
- Idea of the world
Empiricism, conversely, posits that we have no innate ideas; the mind is a tabula rasa, a blank slate or empty box filled only through experience.
- Mathematics as a Model for Science: Mathematics, with its demonstrable and calculable universal truths, serves as the sole guide. Mathematics possesses a necessary, objective, and indisputable nature, unlike opinion-based reasoning. Mathematics offers an objective image reducible to formulas, making it understandable. Descartes believed that philosophical rules should be as clear as those of mathematics.
- The Centrality of Method: Correct thinking is ordered thinking. Errors in reasoning arise from a lack of method and order. A method is a way to arrive at truth. Descartes applied the same methodological principles to both the physical sciences and philosophy, considering them equally valid tools for knowledge acquisition.
- The Fight Against Skepticism: For Descartes, philosophy’s task is to demonstrate the necessity of reason against skeptical doubt to establish rigorous science or knowledge. All rationalists combat skepticism because they believe reason must be autonomous.
- The Rationality of the World: The world and humanity share a common element: rationality. Both are expressions of reason, making objective knowledge possible.
The Historical Context
René Descartes (1596-1650) lived in a Europe embroiled in the Thirty Years’ War, a series of religious conflicts stemming from the Reformation and Counter-Reformation. The seventeenth century was a period of famine, pestilence, and wars, but also of significant scientific discoveries. Descartes chose to live in Holland for its freedom of thought.
Descartes: A Timeline of His Life
A profound event, the “meditation on the stove” (November 10, 1619), marked the moment when Descartes conceived the need for a method and identified the first truth. In 1637, he published Discourse on the Method, which, as its title suggests, is a prologue or explanation of the method that enabled him to write three scientific works: Dioptrics, Meteors, and Geometry. In the Discourse, he provides a short intellectual autobiography (“history of his spirit”) and outlines his epistemological and metaphysical principles. In 1640, he published Meditations on First Philosophy, which lays the metaphysical foundation for science and connects knowledge of God to the certainty of geometry.
Why is Descartes the Father of Modern Philosophy?
Descartes is considered the father of modern philosophy because his work shifts the focus of philosophy to the theory of human knowledge. The fundamental question changes from the essence of being to: “How do we come to know being?” The “I” becomes the conscious starting point (“rationalist anthropocentrism”).
When Descartes says, “I think, therefore I am,” he affirms the autonomy of the thinking subject, the “I.” The central philosophical issue for Descartes and Hume becomes: How does humanity attain knowledge? The subject becomes capable of understanding the world through human knowledge.
Descartes’s doubt was not aimless wandering but a methodical process to combat skepticism and establish a secure foundation for human knowledge. Life requires clear criteria and evidence upon which to build rationally. The process of bracketing knowledge allows us to distinguish what is sufficiently clear and distinct. Cartesian doubt is not skeptical in the sense of destroying everything; it is a methodical, step-by-step process to arrive at truth. Doubt serves as a tool to identify what is certain. The triumph of reason lies in escaping the initial state of doubt and establishing a firm foundation for knowledge [Cogito].
In the first part of Discourse on the Method, Descartes expresses dissatisfaction with the scholastic philosophy he learned from the Jesuits, which he considered mere rhetoric (“means to be admired by the less wise”) and lacking progress. He argued for a process of doubt because clear and distinct ideas are absent in the existing body of knowledge. Cartesian doubt is reason proving itself, not doubt for doubt’s sake, but doubt to establish a better foundation for reason.
The Cartesian Doubt Has Three Characteristics:
- Universal: It encompasses everything – the world, tradition, faith, etc. – anything not clear and distinct.
- Methodical: It is ordered and proceeds step-by-step, following rules of method to avoid skepticism. Descartes never doubts the coherence of his own self; he doubts objects, but not his own existence.
- Theoretical: It is not practical or political. Doubt is justified through reasoning. Descartes excludes ethical and political elements from his doubt.