Chapter 4: The Case for A Priori Scrutability

In the previous chapter, I argued for a restricted version of Conditional Scrutability by arguing that all ordinary truths are a priori scrutable from PQT I. In this chapter I extend those arguments to A Priori Scrutability. In particular, I argue that all ordinary truths are a priori scrutable from PQT I. First, however, it is worth taking some time to clarify the notion of the a priori that I am using. Standardly, the notion of apriority applies most fundamentally to knowledge and justification, and perhaps derivatively to propositions. Typically, one says that a subject knows a priori that p when they know that p with justification independent of experience. A subjects knows a posteriori (or equivalently, knows empirically) that p when they know that p with justification that depends on experience. One can then say that p is knowable a priori, or more simply that p is a priori, when it is possible that someone knows a priori that p. It is somewhat less standard to associate apriority with sentences.1 One could start with the definitions above and simply say that a sentence S is a priori when it expresses an a priori proposition. But to get the right results, this would require a fine-grained Fregean conception of propositions. As I discussed in chapter 2, given my dialectical purposes I cannot simply stipulate this conception of propositions. And given alternative conceptions of propositions, this notion of apriority will behave in quite different ways that will not serve my purposes. So instead I have defined apriority in a way that does not obviously depend on the choice between various accounts of propositions. On this approach, the apriority of sentences is defined in terms of the apriority of thoughts, the mental states that are expressed by sentences. On the definition in Chapter 2, we can say that a thought is a priori justified when it is justified independently of experience. A thought constitutes a priori knowledge when it is a priori justified 1It is worth noting, though, that in Naming and Necessity (e.g. p. 65-66), Kripke often casts his discussion of apriority in terms of the apriority of a sentence for a speaker.