As it has often been noticed by scholars, naturalism is an obvious phenomenon of our time. So obvious that it does not even require epistemological justifications (Audi 2000). Such carelessness is somehow comprehensible: whatever it may be, “naturalism” denotes a concept so vague that has indeed become devoid of content or even, some say, obsolete. In the following paper I will try to develop this topic by moving from an historical-genetic approach by focusing my attention on the mid-century American naturalistic debates. And I wish to do this keeping in mind another coextending debate that is often forgotten. Indeed, one seldom pays attention to the fact that philosophical naturalism took its first steps in the U.S. during the same years...