Descartes' Quest for Certainty: Rebuilding Knowledge

Descartes' Skepticism Towards Scholasticism

The starting point of René Descartes' philosophy is the disillusionment caused by traditional scholastic knowledge. He considered this knowledge entirely insecure, where everything was doubtful, and all issues presented a variety of conflicting opinions. This skepticism extended to philosophy in general and, consequently, to all sciences dependent on it, as none seemed to possess sufficiently secure foundations.

The Tree of Knowledge and the Quest for Certainty

Descartes envisioned knowledge as a unified "great tree," with metaphysics as its roots, physics as its trunk, and various sciences like medicine, mechanics, and morals as its branches. His fundamental objective was therefore to demolish the old, tottering edifice of knowledge and construct a new one on more solid foundations. This new knowledge, he believed, must provide absolute security and certainty.

Modernity's Shift: Subjectivism and Idealism

This concept is typically modern. The focus shifts from the scope of truth (the accurate apprehension of an object) to the security of one's knowledge. This shift involves moving to the point of view of the subject, a concept known as subjectivism. Descartes examined knowledge from the perspective of the knowing subject, focusing on how and what elements are known. This subjectivism eventually evolved into idealism, where the subject is seen as capable of creating the reality it knows. Both subjectivism and idealism are characteristic approaches to knowledge throughout modernity.

The Need for a New Method

The fundamental task to achieve this certainty was to find a new method that could overcome the many shortcomings of previous approaches. For instance, the Aristotelian syllogism, while valid when premises were accepted, lost its value when those premises were doubted. Furthermore, it failed to increase knowledge, merely explaining content already provided by faith or prior assumptions.

Reason as the Universal Foundation

Firstly, this new method needed to be universal, applicable to all sciences, unifying them and avoiding the diversity of opinions. Therefore, the method had to be based on something common to all humans: human reason. Reason, for Descartes, is the faculty to distinguish truth from falsehood. This inherent ability holds immense value for scientific inquiry and must provide security in its application.

However, merely possessing this faculty is insufficient; it must be guided, subjected to rules, and properly directed to perform its two key operations:

• Intuition: The immediate apprehension of self-evident truths.
• Deduction: The inference of necessary conclusions from self-evident truths.

It is not enough to have a good understanding; the main thing is to apply it well.

The Cartesian Method: Simplicity and Discovery

Descartes' method consists of a set of rules that are few, true, and simple. These rules are designed to prevent one from mistaking the false for the true, thereby enabling the increase of knowledge. Here, Descartes again diverged from scholastic traditions, which were largely limited to analyzing already established truths. For Descartes, truth must also be discovered and its certainty assured.

This methodical approach, he observed, was already present in mathematics. For rationalists, mathematics served as the model for all knowledge and the perfect expression of reason. Mathematics alone seemed to resist the criticism leveled against previous knowledge, as its foundations were evident and secure.