 Externalist psychologism, if correct, would pare down the determination base of the social world to one kind of (partly social) entity. It faces hurdles, however. First, it must explain how it avoids circularity—that is, social entities depend on attitudes toward those entities that depend on the social entities themselves. Second and more seriously, it needs to explain why this is a plausible determination base for the social. According to this view, the external world figures profoundly into the determination of the social—but only when it is a constituent of attitudes. Strangely, when the external world is not a constituent of attitudes, it plays no role in the determination of the social.