The fundamental division, however, into which universal and singular judgements enter is not numerical at all, and ignores particular judgements altogether. It is that between such judgements as 'Three-sided figures, as such, are three-angled' and 'This man is tall'. The essential distinction is that in the universal judgement the predicate term is apprehended to belong to the subject through our insight that it is necessitated by the nature of the subject term, while in the singular judgement our apprehension that the predicate term belongs to the subject is based upon the perception or experience of the coexistence of predicate and subject terms in a common subject. In other words, it is the distinction between an _a priori_ judgement and a judgement of perception.[27] The merely numerically universal judgement, and the merely numerically particular judgement[28] are simply aggregates of singular judgements, and therefore are indistinguishable in principle from the singular judgement. If then we ask what conceptions are really presupposed by the kinds of judgement which Kant seeks to distinguish in the first division, we can only reply that the universal judgement presupposes the conception of a connected or systematic whole of attributes, and that the singular judgement presupposes the conception of the coexistence of two attributes in a common subject. Neither kind of judgement presupposes the conception of quantity or the conceptions of unity, plurality, and totality.
[27] I owe this view of the distinction to Professor Cook Wilson's lectures on logic.
[28] 'Some coroners are doctors' of course in some contexts means, 'it is possible for a coroner to be a doctor,' and is therefore not numerical; but understood in this sense it is merely a weakened form of the universal judgement in which the connexion apprehended between subject and predicate terms is incomplete.
The second division of judgements is said to be a division in respect of quality into affirmative, negative, and infinite, i. e. into species which may be illustrated by the judgements, 'A college is a place of education,' 'A college is not a hotel,' and 'A college is a not-hotel'. The conceptions involved are said to be those of reality, of negation, and of limitation respectively. The conception of limitation may be ignored, since the infinite judgement said to presuppose it is a fiction. On the other hand, the conceptions of reality and negation, even if their existence be conceded, cannot be allowed to be the conceptions presupposed. For when we affirm or deny, we affirm or deny of something not mere being, but being of a particular kind. The conceptions presupposed are rather those of identity and difference. It is only because differences fall within an identity that we can affirm, and it is only because within an identity there are differences that we can deny.