  The difference between denying P of S and affirming not-P of S is realized in Ancient Greek as a scopal distinction reflected in word order: S P [not is] (Socrates healthy not-is) vs. S [not P] is (Socrates not-healthy is). As indicated in (6), for Aristotle only sentences can be in contradictory opposition. P and not-P both yield falsity when predicated of a non-existent subject but one or the other of the two terms is truthfully predicable of any existent subject in the relevant domain. P and not-P are “logical contraries” that exclude a true middle, an existent entity which is neither P nor not-P. But naturally occurring cases of prefixal adjectives, those marked by a(n)- in Greek, may involve an unexcluded middle, as do polar contraries or antonym pairs.  Modern grammatical discourse departs from Aristotle in allowing for contradictory terms: middle-allowing contrary adjectives (white/black, happy/unhappy) are distinguished from middle-excluding contradictory adjectives (transitive/intransitive, alive/dead). 