Verificationism

Verificationism is the view that a statement is meaningful or scientifically acceptable only if experience can verify it. Its strict forms treat unverifiable statements as meaningless; weaker forms require only possible confirmation.

Vienna Circle: A group of philosophers and scientists who developed logical positivism in interwar Vienna. The group turned verification into a central criterion for meaningful discourse.
Verification criterion of meaning: A rule that treats a statement as meaningful only when experience could establish its truth or falsity. This is verificationism’s central mechanism for sorting meaningful claims.
Falsifiability: The principle that a scientific claim must risk conflict with possible observations. Popper proposed refutability, rather than verification, as the mark of scientific theories.
Metaphysics: The branch of philosophy that investigates the basic structure and nature of reality. Strict verificationism classifies many traditional metaphysical claims as cognitively meaningless.
Logical positivism: A philosophical movement that sought to ground knowledge in logic and empirical science. Verificationism became its best-known test for distinguishing meaningful claims.
Analytic–synthetic distinction: The distinction between truths grounded in meanings or logic and claims answerable to experience. Logical positivists often paired empirical verification with a separate category for analytic truths.
Pragmatic theory of meaning: An account that explains meaning through practical consequences and patterns of use. It locates meaning in use and consequences rather than a verification test alone.
Theoretical terms: Terms for entities or properties introduced by scientific theories, often not directly observable. Their indirect links to observation challenge a simple test of meaning.
Moritz Schlick: An Austrian philosopher who led the Vienna Circle and defended empiricist philosophy of science. His account of verification helped shape the movement’s criterion of meaning.
Observation sentence: A sentence whose acceptance is tied directly to publicly observable conditions. Observation sentences provide the experiential evidence against which scientific claims are tested.

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