The Vicious Triangle of a Priori Truth, Contingent Truth, and Logical Truth

In this paper, I argue against the view there are contingent a priori truths, and against the related view that there are contingent logical truths. I will suggest that in general, predicates ›a priori‹ and ›contingent‹ are implicitly relativized to circumstances, and argue that apriority entails necessity, whenever the two are relativized to the same circumstance. I will then criticize the idea, inspired by David Kaplan's framework, of contingent contents »knowable under a priori characters.« I will also argue, against Kaplan, that sentences of the form »The actual F is F« do not deserve the status of logical truths, since what they express is neither necessary nor a priori (pace Kaplan). In Naming and Necessity, Saul Kripke claims that there are contingent a priori truths. In Demonstratives, David Kaplan not only endorses this claim, but suggests that the case is even more obvious when formulated with the help of indexicals. Kaplan claims that in the »logic of indexicals,« there are many logical truths that are not necessary. The aim of the present paper is to show that there are no contingent a priori truth – or, more precisely, that something that, at a first glance, we may be tempted to call an »a priori contingent truth« is either a single thing that is a priori with respect to one circumstance and contingent with respect to another circumstance, or two different things, one of which is contingent while the other is a priori. The plan is to propose two rebuttals of Kripke's proposal (sections 2 and 3), followed by two rebuttals of Kaplan's proposal (sections 4 and 5), and end with some critical remarks concerning the idea of contingent logical truths. But first of all, let me clarify how I shall understand the terms a priori, a posteriori, necessary and contingent. A necessary truth is what happens to be the case and could not fail to be the case. A contingent truth is what happens to be the case but could fail to be the case. An a priori truth is what is known, independently of any empirical input, to be the case, while an a posteriori truth is what is known to be the case only given some antecedent empirical knowledge.