Hume’s Empiricism and Skepticism
Hume’s Philosophy
Empiricism
Hume argues that all human knowledge derives directly or indirectly from sensory experience. This empiricist view aligns with Locke’s assertion that “There is nothing in the understanding that has not been received by the senses.” There are no innate ideas. Hume developed a radical empiricist philosophy, distinguishing two dimensions in humans:
- Theoretical knowledge
- Practical action
Hume’s practical concerns include:
- The Moral Problem: How do we establish standards of right and wrong? Hume’s solution: Moral emotivism.
- The Political Problem: What is the basis of political power and the need for rules of justice? Hume’s solution: Political utilitarianism.
- The Problem of Religious Belief: What is the nature, cause, and validity of religious belief? Hume’s solution: Religious agnosticism.
Perceptions and Ideas
According to Hume, we can only know phenomena with a probable character. Our mental contents, called perceptions, always come directly or indirectly from experience. Perceptions can be:
- Impressions: Direct, immediate results of experience. These can be external (from senses) or internal (from reflections, passions, desires, and emotions).
- Ideas: Copies of impressions, weakened in our imagination. Ideas differ from impressions in that they are weaker, always follow impressions, have indirect origins, mediate something, and persist after the impression.
Hume further distinguishes between simple and complex ideas:
- Simple Impressions: Do not support distinction or separation, leading to simple ideas (e.g., the impression of a colored surface).
- Complex Impressions: Allow distinction or separation, leading to complex ideas (e.g., the view of Paris from Montmartre).
Association of Ideas
The imagination associates ideas, either naturally or arbitrarily, following three laws:
- Similarity: The imagination moves from one idea to a resembling idea.
- Contiguity: The imagination moves from one idea to another that is adjacent in space and time.
- Causality: The imagination moves from the idea of an effect to the idea of its cause.
Abstract ideas derive from our imagination. Empirical sciences use inductive generalization, based on the custom of observing the future in accordance with the past.
Causality and Knowledge
For Hume, causality is not derived from experience. What we observe in a causal relationship is temporal priority, spatiotemporal contiguity, and a constant connection in the past, but not a necessary connection in the future. Our knowledge of reality is probable, based on custom and belief.
Hume identifies two types of judgments:
- Judgments of Relations of Ideas: Establish necessary relationships between subject and predicate.
- Judgments of Matters of Fact: Depend on correspondence with empirical observations.
Self, World, and God
We cannot know the self, the world, or God as distinct from our impressions. The idea of self is an association of ideas attributed to a single subject. The idea of the world is contiguous impressions in space and time, referred to an alleged substance for which we have no impression. The idea of God is of an imperceptible being, precluding empirical knowledge.
Consequences of Hume’s Empiricism
- Phenomenalism: Reality is what is shown through impressions.
- Idealism: The only existing reality is that of ideas or perceptions.
- Skepticism: Denies the possibility of certain truths about reality. This skepticism is theoretical.
Moral and Political Philosophy
Moral appraisal is a consequence of feelings of approval or disapproval, based on pleasure or displeasure. Our sense of good and evil comes from feeling, not reason. The purpose of political society is peaceful coexistence. Justice is an agreement between citizens to establish rules governing obligations and promises.
Religion
In religion, we face doubt, uncertainty, and contradiction. We cannot rationally establish religious truths, such as the existence of God, without encountering contradictions.