David Hume: Empiricism and the Limits of Human Reason

David Hume's Theory of Knowledge

Elements of knowledge: The elements of knowledge for Hume are impressions and ideas. These are the contents of consciousness, defined as anything that may be present within the human mind, whether through our senses or the exercise of our thought and reflection.

• Impressions are those perceptions that are presented to the mind with greater force and vivacity.
• Ideas are the result of an operation of the mind on the data previously obtained through impressions. They are images of the impressions that we retain in our minds to remember or think about them.

Critique of Descartes and Rationalism

Critique of the Principle of Causality

Hume provides a deep critique of the concept of causality. He argues that we can only know the relation of cause and effect through experience, not by reasoning or deduction. However, all that experience provides is the constant conjunction of events.

As all thought requires a preceding impression, the idea of a "necessary connection" should come from a previous impression which could only come from experience. What we find in experience is one fact that follows another, but not a necessary connection. For Hume, causality is reduced to an association of ideas based primarily on the habit or custom of seeing two phenomena in succession, always in the same order, and the subsequent belief that the same association of phenomena must necessarily be repeated.

Critique of the Idea of Substance

Hume asserts that substance is an empty concept because it does not correspond to any specific sense impression; instead, it corresponds to a collection of clusters of perceptions. It is an idea formed by the imagination.

The idea of corporeal substance is constructed by the mind from the ideas of sensible qualities, which experience shows to be continuously linked by similarities or contiguities.

Critique of the Idea of the Self and God

The "self" is an idea of the imagination used to bring unity to all perceptual content, but we cannot establish the existence of a substance that serves as its support. If the "I" exists, it is never perceived directly, and we cannot have any clear idea of it. If it exists at all, it is like a "bundle of perceptions" which leads us to believe in the existence of a substance.

For the same reason, we cannot affirm the existence of God. To do so would imply that God is the object of some of our impressions, yet God is beyond all of them. Between our impressions and God, no demonstrative connection can be established.