Abstract
In May 1867, when he was twenty-seven years of age, Charles Peirce read a paper to the American Academy of Arts and Sciences that was published in the next year under the title ‘On a New List of Categories’ (EP 1:1–10).1 It is remarkable for anticipating major features of his later thought: three categories relationally defined (bracketed, however, by two additional categories); a theory of signs, triadically conceived and triadically sub-divided, applied to thinking; the idea that every predicate is an hypothesis; a form of abstraction named ‘prescision’; and a bold reconception of the Roman/medieval trivium. Prescision was used here to distinguish the categories and it was put to similar use much later in the..