Hume’s Critique of Causality and Metaphysics

Hume on Matters of Fact and Causal Reasoning

Text 4, p. 75: All our reasonings concerning matters of fact seem to be based on the relation of Cause and Effect. By means of that relation alone we can go beyond the evidence of our memory and senses. Factual issues concerning the future are established through causal reasoning. Events happen to others.

The issues of fact in this text refer to judgments about things happening in the world that we perceive through our senses. These judgments are synthetic, meaning the predicate is not contained within the subject, and they are always informative. If we deny them, it does not result in a contradiction, but in a false statement. The difficulty lies in those judgments that refer to the future, i.e., those that speak of nature as universal. These statements are derived from establishing causal reasoning, an idea that Hume will critique.

Hume’s Criterion for Discriminating Ideas

Hume uses the criterion of discriminating ideas and determines that the idea of cause does not originate from sense impressions. We cannot establish the causes and effects of events through reason alone, unless we have experienced them. We cannot observe causation itself, but only causal conjunctions. There are events that happen to others, and the repetition of a sequence, called constant conjunction, generates the belief in a necessary connection. In conclusion, for Hume, science is based on belief.

Hume’s Rejection of Metaphysics and Theology

Text 3, p. 74: Hume gives no value to books of theology and metaphysics, considering them baseless claptrap and not science. There are only two types of knowledge: relations of ideas and matters of fact. Metaphysics concerns neither one nor the other; therefore, alleged metaphysical knowledge is merely words.

Limits of Knowledge and Critique of Substance

Commentary: The limits of our knowledge are proportionate to our senses. Hume used his criterion for the discrimination of ideas, which allows us to differentiate when an idea is true and when it is false, to deny metaphysics. He starts with the idea of substance. This idea is defined as a set of impressions given in experience. However, there is no single impression that corresponds to “the idea” of substance. Therefore, there is no such idea, as there is no corresponding impression, and we cannot attain any knowledge of it. This is how he negates the idea of mind or self, the external world, and God.

He also critiques the arguments that demonstrate the existence of God. A priori arguments, which start from the idea of God, have no demonstrated foundation because there is no such idea. A posteriori arguments, which attempt to demonstrate the existence of God as a possible cause of something, do not make sense, since causal links can only be established between facts. Therefore, Hume recommends that books on metaphysics and theology be discarded as claptrap.

The Principle of Immanence

Text 1: We only have access to mental contents presented by our senses – this is the principle of immanence. We can only be sure that there are perceptions. What is present in the mind are unique perceptions. It is not possible to establish the existence of something *through* perceptions. We can only determine that something exists if we have experienced constant conjunctions and, from there, establish a causal nexus.

• The limits of our knowledge are the limits of our experience.
• We can only connect what we experience (through constant conjunctions).
• Hume is a *de facto* atheist, although he admits that he cannot definitively prove or disprove God’s existence.

We only have reason and sense. Hume focuses on perception and describes ideas.