self-reference, paradoxes of See RUSSELL, TYPE. THEOR. self-referential incoherence, an internal defect of an assertion or theory, which it possesses provided that (a) it establishes some requirement that must be met by assertions or theories, (b) it is itself subject to this requirement, and (c) it fails to meet the requirement. The most famous example is logical positivism’s meaning criterion, which requires that all meaningful assertions be either tautological or empirically verifiable, yet is itself neither. A possible early example is found in Hume, whose own writings might have been consigned to the flames had librarians followed his counsel to do so with volumes that contain neither ‘abstract reasoning concerning quantity or number’ nor ‘experimental reasoning concerning matter of fact and existence.’ Bold defiance was shown by Wittgenstein, who, realizing that the propositions of the Tractatus did not ‘picture’ the world, advised the reader to ‘throw away the ladder after he has climbed up it.’ An epistemological example is furnished by any foundationalist theory that establishes criteria for rational acceptability that the theory itself cannot meet. See also HUME, LOGICAL POSI- TIVIS. W.Has.