抄録
This paper considers the public nature of language. Should we assume that a speaker's language can be understood by anyone who has sufficient evidence and rationality ? Or should we assume that it need not necessarily be understood by everyone, but only by those who share conceptual scheme? This question connects to the question of intelligibility of the idea of different conceptual schemes. And the question of the intelligibility of different conceptual schemes ultimately leads to the question of whether intelligibility requires epistemic conditions. The argument considered in this paper is based on the fact that concepts such as language and truth are theoretical concepts. And it is made clear that, at least in that argument, it does not follow that epistemic conditions are required.