taneously accepting that view and disputing the opposite until a few unquestionably abstract nouns are shown to be general. But a large number of abstract terms have only a singular import, and as concrete singulars have only contradictories, and neither contraries, sub-contraries nor subalterns, the property of singularity in abstract proportions must limit their opposites. I may, therefore, supplement the ordinary canons of Opposition by the following rules, designed to give Opposition greater practical value:
1. All singular propositions, whether concrete or abstract, have only contradictories.
2. Definitive, or individuo-universal propositions also have only contradictories.
3. Collective universals have universal contradictories while their particular contraries are of the same quality with themselves and the subalterns are of the opposite quality.
4. Partitive particulars make A and E, A and I, and E and O contradictories, while a peculiar relation of subalternocontradiction exists between A and O and E and I, and I and O are reciprocals.
5. Only distributive universals and indefinite particulars follow the ordinary canons of Opposition.
Even these laws can be supplemented by still others founded upon a different set of conditions. Thus far I have assumed that the propositions remain formally the same, but differ in contents or meaning. This, of course, is only a distinction between their grammatical or linguistic and their thought form, but it is sufficient to modify the rules for Opposition which must be based upon the thought form when it comes to practical reasoning and discourse. But there is an application of the principles of Opposition which is independent of the purely formal character of propositions, and it comes into use where the rules we have indicated are not applicable. It is based upon the relations of terms which are congruent, or inconsistent with each other, or partly congruent and partly inconsistent with each other. They are the generic and specific terms which are very often used in relations implying
