 We use \(\copy A\) to represent any contrary of \(A\). Following the Aristotelian theory of opposition, the two contradictories \(A\) and \(\neg A\) cannot both be false, just as they cannot both be true, while a given proposition and a contrary of that proposition, \(A\) and \(\copy A\), can both be false, although they cannot both be true. (Others have used \(\kappa\) or R for one-place non-truth-functional contrariety connectives; cf. McCall 1967, Humberstone 2005; see also Bogen 1991 for the distinction between linguistic and metaphysical contraries.) It should be noted that while \(\neg\) is an operator that takes one proposition into another, © is not, since a given proposition may have logically distinct contraries, while this is not the case for contradictories. Geach (1972, 71–73) makes this point with the example in (8). While (8a) has two syntactically distinct contradictories, e.g., Not every cat detests every dog and It’s not every dog that every cat detests, any such co-contradictories of a given proposition will always have the same truth conditions. But (8a) allows two contraries with distinct truth conditions, (8b) and (8c).