(i) necessity, for 'experience teaches us that a thing is so and so, but not that it cannot be otherwise', and
(ii) universality, for all experience can confer on a judgement is 'assumed and comparative universality through induction'.
Gottlob Frege stressed that the issue was one of justification, and defined an a priori truth as one whose proof rests exclusively on general laws which neither need nor admit of proof, while a truth which cannot be proved without appeal to assertions about particular objects is a posteriori.
Statements such as 'A vixen is a fox', whose truth is analytic, are accorded a priori status without dispute. Kant held that in addition truths of arithmetic and geometry, and such statements about the natural world as 'Every event has a cause', were not analytic but nevertheless had the hallmarks of being a priori. The central question that his philosophy addressed was how such synthetic a priori truths were possible, whereas the strategy of his 20th-century empiricist critics was to argue that there are no a priori truths that are not analytic.
(Published 1987)
— J. E. Tiles
- Bibliography
- Frege, G. (1959). The Foundations of Arithmetic. Trans. J. L. Austin, section 3.
- Kant, I. (1929). The Critique of Pure Reason. Trans. N. Kemp-Smith, Preface and Introduction.
