Are Beliefs About Psychological States Incorrigible?
We want to find out whether a belief can justify itself, in the sense of guaranteeing its own truth. There are (at least) two ways in which this might occur, and each will be discussed in turn. Every belief has two components, an “act” of believing, and a content, what is believed. In some very limited cases, the very act of believing brings it about that the belief is true. The act of believing that I exist requires my existence in order to take place at all. So the act of believing that I exist guarantees the truth of the content, that I exist. Similarly, the act of believing that I believe something guarantees the truth of the content, that I believe something. [But note that the act of believing that I believe, say, that Nome is in Alaska, does not guarantee the truth of the content, that I believe that Nome is in Alaska. It seems possible that I may be mistaken about whether I believe that very specific proposition.] There are not many beliefs whose truth is guaranteed by the very
