Concept

Hume's fork

Overview

In epistemology, Hume's fork is a tenet elaborating upon British empiricist philosopher David Hume's emphatic division between "relations of ideas" and "matters of fact." (Alternatively, Hume's fork may refer to what is otherwise termed Hume's law, a tenet of ethics.) As phrased in Immanuel Kant's characterization of Hume's thesis, and furthered in the 1930s by the logical empiricists, Hume's fork asserts that all statements are exclusively either "analytic a priori" or "synthetic a posteriori," which, respectively, are universally true by mere definition or, however apparently probable, are unknowable without exact experience.

By Hume's fork, a statement's meaning either is analytic or is synthetic, the statement's truth—its agreement with the real world—either is necessary or is contingent, and the statement's purported knowledge either is a priori or is a posteriori. An analytic statement is true via its terms' meanings alone, hence true by definition, like Bachelors are unmarried, whereas a synthetic statement, concerning external states of affairs, may be false, like Bachelors age badly. By mere logical validity, the necessary is true in all possible worlds, whereas the contingent hinges on the world's state, a metaphysical basis. And the a priori is knowable without, whereas the a posteriori is knowable only upon, experience in the area of interest.

By Hume's fork, sheer conceptual derivations (ostensibly, logic and mathematics), being analytic, are necessary and a priori, whereas assertions of "real existence" and traits, being synthetic, are contingent and a posteriori. Hume's own, simpler, distinction concerned the problem of induction—that no amount of examination of cases will logically entail the conformity of unexamined cases—and supported Hume's aim to position humanism on par with empirical science while combatting allegedly rampant "sophistry and illusion" by philosophers and religionists. Being a transcendental idealist, Kant asserted both the hope of a true metaphysics, and a literal view of Newton's law of universal gravitation by defying Hume's fork to declare the "synthetic a priori." In the 1930s, the logical empiricists staked Hume's fork. Yet in the 1950s, W. V. O Quine undermined its analytic/synthetic distinction. And in the 1970s, Saul Kripke established the necessary a posteriori. Still, Hume's fork is a useful starting point to anchor philosophical scrutiny.

Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).

Possible passages

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But all philosophy is either cognition on the basis of pure reason, or the cognition of reason on the basis of empirical principles. The former is termed pure, the latter empirical philosophy. The philosophy of pure reason is either propædeutic, that is, an inquiry into the powers of reason in regard to pure à priori cognition, and is termed critical philosophy; or it is, secondly, the system of pure…
Immanuel Kant, The Critique of Pure Reason
States what Hume's fork is; the author is tied to Hume's fork in the knowledge graph.
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The will, regarded as the faculty of desire, is (in this view) one of the many natural causes in the world, viz. that cause which acts in accordance with concepts. All that is represented as possible (or necessary) by means of a will is called practically possible (or necessary); as distinguished from the physical possibility or necessity of an effect, whose cause is not determined to causality by concepts (but in…
Immanuel Kant, Kant's Critique of Judgement
States what Hume's fork is; the author is tied to Hume's fork in the knowledge graph.
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The Critical theory starts originally from the distinction of elements presented in the analysis of experience, viz. the matter of sense, and its universal relations. Taking into account Hume's criticism on this distinction as given in the preceding section, viz. that sensation does not explicitly apprehend more than an individual or more than a mere event, it insists at the same time on the _fact_ that universality…
Georg Wilhelm Friedrich Hegel, The Logic of Hegel
States what Hume's fork is.
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Philosophers who discussed Hume's fork

David Hume

Related ideas

Place in the tradition

Part of Deductive-nomological model.

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