ABSTRACT
The idea of a relative a priori goes back to Reichenbach’s The Theory of Relativity and A Priori Knowledge (1920) and was developed by Carnap as a theory of linguistic frameworks in Logical Syntax of Language (1934). This chapter discusses an underlying tension. On the one hand, the official position of logical empiricism is that there is no synthetic a priori at all because all knowledge can be shown to be either empirical or simply a matter of definition. On the other hand, several topics considered to be a priori by Kant remained central topics for them. The chapter shoes how Reichenbach discussed this view with Schlick early on, how Carnap developed their view of the relative a priori further, and how this view continued to be influential.
