Substance and Causality: Hume’s Empiricist Skepticism
The Problem of Complex Ideas: Substance and Causality
Substance and causality are two fundamental ideas in the construction of arguments. A fundamental part of knowledge is built on the belief that one can establish causal chains linking substances. The problem is that it is not possible to prove these concepts from simple ideas given by experience. Locke, an empiricist who could be called common sense, is forced to accept indemonstrable ideas, such as the existence of external reality and causality.
Hume’s Skepticism and Empiricism
David Hume could be considered the most consistent skeptic philosopher in the history of philosophy. He represents the culmination of empiricist thought.
Hume clearly claims:
- Skepticism: The human world is not one of absolute truths, but of probable and changing truths.
This involves his theory of knowledge:
- A review of the criterion of truth, through the “copy principle”: the idea that truth is only what we know comes from an impression.
- A criticism of the ideas of substance and cause, as there is no evidence of any sensible impression for them.
- An examination of the pseudo-concepts of “I”, God, and World (the three ideas of reason, which according to Descartes were innate, spontaneous productions of the mind).
- Emotivism: Ethics has its origins in feelings. Individuals have no impressions or ideas on which to base our moral ideas, and in fact, in most of our actions, we tend to be guided more by passions than by ideas.
Experience: The Source of All Knowledge
The Origin of Ideas
The empiricist movement ends with Hume. Hume is more radical and takes empiricism to its limit, extracting the inevitable consequences that his predecessors did not fully articulate.
Descartes said the search for knowledge must begin with the analysis of the subject. Hume believes that we must admit that initially we only know that some of the representations that appear in consciousness are very sharp and intense, while others are not. The former are called impressions (which may be of sensation or reflection), and the latter are called ideas.
Hume sets the fundamental rule of his work, the correspondence principle: there can be no ideas without corresponding impressions; all ideas are ultimately derived from impressions.
Simple and Complex Ideas
In the mind, there are ideas that do not reproduce any particular impression, but that is because not all ideas are simple. There are complex ideas resulting from the aggregation in the mind of several simple ideas. Simple ideas must inevitably come from previously received impressions.
Two Kinds of Knowledge
- Relations of ideas: These are mathematical and logical propositions, which have a necessary character tied to the very definition of things, independent of whether they exist or not. Relations of ideas constitute the greatest certainty, but they do not inform us of the existence of any object; they only state the conditions that would necessarily apply to an object if it existed.
- Matters of fact: These concern what actually happens; we know them from experience and not by demonstration. These do not possess the necessary character that distinguishes relations of ideas: they are contingent.
There is nothing in our knowledge beyond relations of ideas and matters of fact arising in one way or another from experience. Much of Hume’s work raises the question of the extent to which our knowledge of these matters is grounded in fact and what its scope is, or, put another way, what its boundaries are.
The Critique of Metaphysics
Three concepts are crucial in the foundation of knowledge: general definitions, substance, and causality.