a specific way; by adulthood there are strong implicit intuitions about "truth" that form a "folk theory" of truth. These intuitions include: Capture (T-in): If P, then P is true Release (T-out): If P is true, then P Noncontradiction: A statement can not be both true and false Normativity: It is usually good to believe what is true False beliefs: The notion that believing a statement does not necessarily make it true Like many folk theories, the folk theory of truth is useful in everyday life but, upon deep analysis, turns out to be technically self-contradictory; in particular, any formal system that fully obeys "capture and release" semantics for truth (also known as the T-schema), and that also respects classical logic, is provably inconsistent and succumbs to the liar paradox or to a similar contradiction. Notable views Ancient Greek philosophy Socrates', Plato's and Aristotle's ideas about truth are seen by some as consistent with correspondence theory. In his Metaphysics, Aristotle stated: "To say of what is that it is not, or of what is not that it is, is false, while to say of what is that it is, and of what is not that it is not, is true". The Stanford Encyclopedia of Philosophy proceeds to say of Aristotle: [...] Aristotle sounds much more like a genuine correspondence theorist in the Categories (12b11, 14b14), where he talks of "underlying things" that make statements true and implies that these "things" (pragmata) are logically structured situations or facts (viz., his sitting, his not sitting). Most influential is his claim in De Interpretatione (16a3) that thoughts are "likenesses" (homoiosis) of things. Although he nowhere defines truth in terms of a thought's likeness to a thing or fact, it is clear that such a definition would fit well into his overall philosophy of mind. [...] Similar statements can also be found in Plato's dialogues (Cratylus 385b2, Sophist 263b). Some Greek philosophers maintained that truth was either not accessible to mortals, or of greatly limited accessibility, forming early philosophical skepticism. Among these were Xenophanes, Democritus, and Pyrrho, the founder of Pyrrhonism, who argued that there was no criterion of truth. The Epicureans believed that all sense perceptions were true, and that errors arise in how we judge those perceptions. The Stoics conceived truth as accessible from impressions via cognitive grasping. Medieval philosophy Avicenna (980–1037) In early Islamic philosophy, Avicenna (Ibn Sina) defined truth in