This paper addresses a problem about epistemic warrant. The problem is posed by philosophical arguments for externalism about the contents of thoughts, and similarly by philosophical arguments for architecturalism about thinking, when these arguments are put together with a thesis of first person authority. In each case, first personal knowledge about our thoughts plus the kind of knowledge that is provided by a philosophical argument seem, together, to open an unacceptably ‘non-empirical’ route to knowledge of empirical facts. Furthermore, this unwelcome (...) prospect of transferring a ‘non-empirical’ warrant from premises about our own mental states and about philosophical theory to a conclusion about external environment or internal architecture seems to depend upon little more than the possibility of knowledge by inference. (The use of the scare-quoted term ‘non-empirical’ is explained a couple of paragraphs further on.). (shrink)