Descartes vs Hume: Rationalism, Empiricism, and Modern Thought

Descartes, Rationalism, and the Enlightenment

René Descartes' philosophy significantly influenced the course of thought, paving the way for the 17th-century Enlightenment. The freedoms proclaimed during the Enlightenment—such as the autonomy of reason over the weight of authority and religious dogmatism in fields from politics to science—can be considered progress that contributes to our freedoms today.

The Mathematization of Reality

Regarding mathematization and scientific-technical development, Descartes proposed a method heavily influenced by mathematics. Contemporary Western science often continues under the premise that reality is mathematicizable. Knowing things involves quantifying them, and the mathematical model remains central to scientific inquiry.

Reason, Faith, and God

Moreover, contemporary philosophy generally no longer insists on demonstrating the existence of God, a task that greatly troubled Descartes. Philosophy now largely separates the realms of reason and faith.

The Evil Genius and Modern Parallels

Descartes' evil genius argument finds a modern update in films like The Matrix. This production describes a world inhabited by humans who, believing they perceive the world through their senses, are actually experiencing electrical impulses controlled by a powerful computer system. This vast computer acts as the "evil genius," imposing a digital reality.

Empiricism: A Reaction to Rationalism

Empiricism emerged as a reaction against rationalism. The most significant empiricist philosophers include John Locke and David Hume. We will focus on Hume's philosophy for comparison with Descartes.

Core Tenets of Empiricism

Empiricism is characterized by its rejection of nativism. Empiricists argue there are no innate ideas or principles; the understanding is initially a tabula rasa (blank slate) upon which knowledge is written through sense experience.

Comparing Descartes and Hume

Methodology and Knowledge Acquisition

Both rationalism and empiricism share a methodological purpose, but differ significantly:

• Empiricists (Hume): Employ an inductive method, starting with experience and based on the analysis of facts.
• Rationalists (Descartes): Utilize a deductive and mathematical approach. Knowledge is reduced to self-evident principles or innate ideas.

Criterion of Truth

For Descartes, the criterion of truth is clarity and distinctness – an idea being perceived clearly and distinctly. Hume's source of knowledge and criterion for truth lies in sense impressions.

The Existence of God

Descartes used the argument from causality and the ontological argument to demonstrate God's existence. For Hume, however, the concept of God cannot be validated because we have no direct sense impression of God.

The Self or Personal Identity

Hume asserts that we have no single impression of our "self." Instead, what we call the self is merely a succession of perceptions linked by memory. Conversely, for Descartes, the thinking substance (cogito ergo sum - "I think, therefore I am") is the foundational, first truly clear and distinct certainty of his method.