Descartes vs. Hume: Rationalism and Empiricism in Philosophy

Descartes vs. Hume: A Philosophical Comparison

René Descartes: Rationalism

Source of Knowledge

• Reason is the source of knowledge.
• Through his innate ideas, one can arrive at any knowledge of the world.
• From certain definitions, he deduced his entire philosophy (substance, attribute, and modes).

Criterion of Truth and Research Model

• The criterion of truth is evidence.
• Experience was considered confusing, and even the proper use of ideas brings knowledge.
• Truth must be sought within the mind, following a rigorous method based on a priori order.
• Intellectual experience, through abstraction from the contents of the world (meditation), reveals strict eternal truths that God has implanted in the human soul.
• Research model based on mathematics.

Key Truths and Concepts

• First Truth: The Cogito (self-evident).
• Second Truth: The Unity of Substance (referring to God as the ultimate, unified substance).
• Third Truth: God as the cause of the idea of perfection.
• The idea of cause is independent of the subject. God is the foundation of absolute knowledge.
• God is the cause of being and knowing. This cause involves the idea of necessary connection, independent of human thought.
• The most radical argument: The Ontological Argument (presupposes the existence of God without recourse to creation; essence implies existence).

Understanding and Substance

• Understanding captures essences: Substance.
• Substance: Something that exists in such a way that it needs no other thing in order to exist.
  • Thinking Substance (Res Cogitans): The mind/self (ideas: innate, adventitious, factitious).
  • Divine Substance (God): Infinite perfection.
  • Extended Substance (Res Extensa): Body/matter (characterized by extension).

David Hume: Empiricism

Source of Knowledge

• The senses are the source of knowledge.
• All our ideas are derived from our impressions. Ideas are acquired.
• From observation and experience, particularly through trial and error, knowledge is acquired, leading to probabilistic rather than universal inductions.

Criterion of Truth and Research Model

• Immanence criterion: The first and original impression is paramount; therefore, ideas alone do not provide knowledge. Knowledge is receptive.
• There are no innate ideas. A priori concepts of Cartesianism are neither true nor false (they lack meaning, leading to a dead end in metaphysics).
• The order in research is unimportant. There is no guarantee of transcendent knowledge.
• The model is in physics: knowledge is explained on the basis of the inherent attraction of impressions and ideas, regularly through the association of ideas.

Criticism of Key Concepts

• No self-evident truths. Diversity of views, united by imagination. We have no impression of abstract concepts.
• Criticizes the idea of cause: It is formed without a corresponding impression, linking ideas arbitrarily. Only natural causation is possible, dependent on human experience.
• Impressions and ideas are presented in our memory according to the laws of association of ideas:
  • Similarity
  • Contiguity
  • Constant Conjunction (Causality)

Belief and Existence

• Belief: Assumes knowledge of the existence of objects. However, the idea of existence adds no new quality to an object. We cannot *rationally demonstrate* the existence of objects of belief (contrasting with Descartes' idea of God).

Sensitivity and Impressions

• Sensitivity captures impressions.