Sec. 8.  The distinction between Positive and Negative terms is not of much value in Logic, what importance would else attach to it being absorbed by the more definite distinction of contradictories.  For contradictories are positive and negative in essence and, when least ambiguously stated, also in form.  And, on the other hand, as we have seen, when positive and negative terms are not contradictory, they are misleading.  As with ‘wise-unwise,’ so with many others, such as ‘happy-unhappy’; which are not contradictories; since a man may be neither happy nor unhappy, but indifferent, or (again) so miserable that he can only be called unhappy by a figure of speech.  In fact, in the common vocabulary a formal negative often has a limited positive sense; and this is the case with unhappy, signifying the state of feeling in the milder shades of Purgatory.

When a Negative term is fully contradictory of its Positive it is said to be Infinite; because it denotes an unascertained multitude of things, a multitude only limited by the positive term and the suppositio; thus ‘not-wise’ denotes all except the wise, within the suppositio of ‘intelligent beings.’  Formally (disregarding any suppositio), such a negative term stands for all possible terms except its positive:  x denotes everything but X; and ‘not-wise’ may be taken to include stones, triangles and hippogriffs.  And even in this sense, a negative term has some positive meaning, though a very indefinite one, not a specific positive force like ‘unwise’ or ‘unhappy’:  it denotes any and everything that has not the attributes connoted by the corresponding positive term.

Privative Terms connote the absence of a quality that normally belongs to the kind of thing denoted, as ‘blind’ or ‘deaf.’  We may predicate ‘blind’ or ‘deaf’ of a man, dog or cow that happens not to be able to see or hear, because the powers of seeing and hearing generally belong to those species; but of a stone or idol these terms can only be used figuratively.  Indeed, since the contradictory of a privative carries with it the privative limitation, a stone is strictly ‘not-blind’:  that is, it is ‘not-som
ething-that-normally-having-sight-wants-it.’

Contrary Terms are those that (within a certain genus or suppositio) severally connote differential qualities that are, in fact, mutually incompatible in the same relation to the same thing, and therefore cannot be predicated of the same subject in the same relation; and, so far, they resemble Contradictory Terms:  but they differ from contradictory terms in this, that the differential quality connoted by each of them is definitely positive; no Contrary Term is infinite, but is limited to part of the suppositio excluded by the others; so that, possibly, neither of two Contraries is truly predicable of a given subject.  Thus ‘blue’ and ‘red’ are Contraries, for they cannot both be predicated of the same thing in the same relation; but are not Contradictories,