David Hume’s Philosophical Legacy: Empiricism, Skepticism, and Ethics
David Hume’s Core Philosophy
Impressions and Ideas: Foundations of Knowledge
David Hume distinguished between impressions (vivid sense experiences) and ideas (fainter mental representations derived from impressions).
Hume’s Two Types of Knowledge
He categorized knowledge into two types:
- Relations of Ideas: Ideas formed from relationships between analytical propositions (e.g., mathematics).
- Matters of Fact: Knowledge based on experience.
Critique of Human Reason and Causality
Hume’s Skepticism on Human Reason
Hume argued that our knowledge of external objects and future events is limited to current and past impressions and actual memories. We have no impressions of future events, and our actions concerning the future are based solely on what we have experienced in the past, through causal inference.
Causation and Necessary Connection
The idea of cause is often reflected in us as a necessary relationship between cause and effect.
Challenging Necessary Connection
Hume criticized this idea, stating that we cannot observe the causes causing the effects. Therefore, there is no observable necessary connection between the two. The only thing observable is that one event occurs after another, and this sequence is consistent, but not necessarily so. Thus, we can never know if it will happen again. We hold this belief due to habit.
Hume on Existence and Reality
Belief vs. Knowledge: Unobservable Events
Certainty about the existence of unobservable events is not based on knowledge but on belief. Causal inference is applicable only to impressions.
Skepticism Towards External Reality
We cannot have certainty of the existence of a global external reality. We only know our own impressions and only have access to them; therefore, we cannot infer an external world beyond them.
The Existence of God: A Belief, Not Knowledge
Based on his empiricist epistemology, Hume concluded that God’s existence cannot be known. God is a belief, but we do not know where the impressions for such a belief come from.
Self, Identity, and Phenomenalism
The Self and Personal Identity
Against Descartes and Locke, Hume argued that the existence of the self cannot be justified by appealing to a supposed intuition of oneself. We only have intuition about our ideas and impressions, and no impression is permanent; rather, they succeed each other uninterruptedly. The self, therefore, is not a substance distinct from impressions and ideas.
Hume explained the sense of self-identity by appealing to memory, which allows us to recognize the connection between different impressions that succeed each other. The error lies in confusing a continuous stream of impressions with a fixed, unchanging identity.
Phenomenalism and Humean Skepticism
Human knowledge is a “patchwork” of impressions and ideas that are associated with each other.
- In impressions, we can find no explanation or rationale whatsoever.
- Regarding how perceptions are linked to one another, it is not possible to discover real connections between them, but only their sequence.
Reality is thus reduced to mere impressions or phenomena. This is the meaning of phenomenalism, and it leads to a skeptical attitude towards the world and reality.
Hume’s Moral Philosophy and Religion
Critique of Moral Rationalism
A moral code is a set of judgments through which we express approval or disapproval of attitudes. Hume argued that intellectual knowledge (reason) cannot be the foundation of our moral judgments. Reason does not compel us; therefore, moral judgments do not originate from reason.
Mathematics is useful for life, but its knowledge, while urging us to apply it, finds its application when pursuing a goal or objective that does not come from mathematics itself. Factual knowledge, however, merely shows what is, and facts are not moral judgments. The knowledge of things shows us how things are, not how they should be. To move from the realm of “is” to “ought” would be a fallacy.
Religion: Rooted in Feeling, Not Reason
The deist conception of divinity and natural religion was based on the idea of a rational human nature. Hume, by denying this rational nature, thus rejected deism and natural religion. Religion, for Hume, does not have its primary principle in reason; it arises from feeling, with a strong psychological basis.