David Hume's Empiricism: Challenging Cartesian Philosophy

The Foundation of Empiricism

David Hume is one of the leading philosophers of empiricism. He proposes a philosophy that considers something true only if it is based on experience or impressions. One important aspect that characterizes his thought is the negation of the Cartesian philosophy of res cogitans. He denies the res infinita and res extensa.

The Origin of Knowledge

As for the origin of knowledge, experience reduces all to sensitive evidence. For empiricists, experience is the fundamental concept of philosophy, as it differentiates what is true from what is not. No one can say that something is true if they have no experience of it. For this reason, Hume denies the validity of abstract ideas and distinguishes two types of ideas:

• Relationships of ideas: These are universal and necessary relations that are independent of experience (i.e., they are deductive and derived from the principle of contradiction).
• Matters of fact: These are propositions with empirical content (inductive) that provide probable knowledge (i.e., they are what can be compared).

Determining Truth Through Sensory Perceptions

How do we know if something is true? According to Hume, something is known to be true only through sense perceptions. There are three types of sensory perceptions:

1. First impressions: These are the data obtained by immediate sensory experience. They are divided into two types:
   • Physical sensations (sense impressions)
   • Feelings of reflection (realizing what you feel)

   These two differ in that, for example, when you are asleep, you have a physical impression but not a sense of reflection.

2. Ideas: Impressions produce ideas, which are copies of our initial impressions, stored in our memory. To determine if these are true copies, we must see if we remember the impression from which they originate.
3. Association of ideas: Finally, an association of ideas is established, where ideas are linked by bonds that form our thinking. That is, ideas do not appear in isolation, but the imagination is responsible for linking them, establishing different connections.

The Principle of Association of Ideas

In this connection, Hume establishes the principle of association of ideas, by which the imagination mixes and matches sensations according to its preference. Beliefs arise in our minds through three laws of association of ideas:

• Law of similarity: Beliefs arise when, repeatedly, like causes always produce like effects.
• Law of contiguity: The mind generates a belief when invariably the same effect is always accompanied by one and the same cause.
• Law of necessary connection between cause and effect: The mind creates a belief when the cause precedes the effect temporarily.

The two previous laws depend on this third law, which is the law of causality. However, Hume refutes this law and, consequently, the other two laws that depend on it.

Challenging the Relationship Between Phenomena

Hume also believes there is no relationship between different phenomena. This relationship is known by reason. He considers that phenomena are a "constant conjunction" between one thing and another, but not a "necessary connection." The "constant conjunction" is perceived significantly, but there is no sense impression of the "necessary connection." The "necessary connection" is not an empirical objective but a subjective sentimental belief. Empirical phenomena are perceived as always being sensitively related, but causality is not an intelligible law of reality but only a sensible belief (believe) that dominates our sensibility.

The Principle of Causality and Descartes' Certainties

With all this, Hume demonstrates that the principle of causality does not have an ontological dimension but only an epistemological dimension. That is, the principle of causality does not exist in reality; it is just a belief. He denies its existence since we have no impression of this principle. This is the first denial. The other three denials concern the certainties of Descartes:

1. Rejection of the idea of self: Hume's critique of substance affects the human spiritual substance, the soul. As we have no impressions of the soul, we cannot say it exists.
2. Denial of the idea of God: He believes that a posteriori proofs of the existence of God are invalid. Moreover, by denying the principle of causality, he rejects God as the First Cause.
3. Rejection of the idea of the world: The idea of substance is a figment of the imagination; if we remove the accidents, we have nothing. We cannot talk about things or events, but only our impressions of things or phenomena (phenomena).

Ethics and Utilitarianism

In ethics, Hume shows the influence of Hutcheson and values actions based on the pleasure they produce (utilitarianism). He also addresses the naturalistic fallacy, stating that in the world, there are only facts, and we cannot theorize about what should be.