Published online by Cambridge University Press: 01 January 2020
According to one understanding of them, Tarskian principles about truth (and falsity) aim to explicate the core of the classical conception of truth (and falsity), as endorsed by Aristotle and others:
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, or of what is not that it is not, is true, so that he who says of anything that it is, or that it is not, will say either what is true or what is false. Metaphysics (Book IV.7, 1011ª: 26–8)
Timothy Williamson famously offered an argument from these Tarskian principles in favour of bivalence — the contention that whatever says something is either true or false — to the effect that denying bivalence in particular cases classically entails a contradiction. This has played a crucial role in the reception of Williamson's case against the main alternative classical view of the nature of vagueness, supervaluationism, and thus in favor of his own epistemic view.