The thesis of this paper is that in dealing with problems of "mind," the philosopher of mind needs to be as well grounded in his relevant sciences (e.g. psychology, anthropology) as the philosopher of the physical sciences needs to be grounded in his relevant sciences (e.g. physics). The thesis of this paper is also that the psychological analysis of solipsism and the philosophical analysis are not independent (or at least not independent in all of their aspects), and that therefore the (...) psychological analysis sheds light on the philosophical, and vice versa. It is argued that solipsism is untenable on at least two grounds: because (1) there are no such physical phenomena as acts of "immediate perception," and because (2), that there can be no such thing as an "individual mind" without some form of a "group mind.". (shrink)