This paper is a discussion of the tenability of methodological solipsism, which typically relies on the so-called Explanatory Thesis. The main arguments in the paper are directed against the latter thesis, according to which internal (or autonomous or narrow) psychological states as opposed to noninternal ones suffice for explanation in psychology. Especially, feedback-based actions are argued to require indispensable reference to noninternal explanantia, often to explanatory common causes. Thus, to the extent that methodological solipsism is taken to require the truth (...) of the Explanatory Thesis, it, too, can be regarded as untenable. (shrink)