Substantives and Adjectives were both formerly included under the term Nouns or Names; and we have still to distinguish, when they are under special consideration, as they are here, Nouns Substantive, and Nouns Adjective.
By regarding all the Oblique Cases of Nouns Substantive as a species or variety of Nouns Adjective, and so classifying them along with the Adjectives proper, the Nominative Case alone remains to represent the Substantive, in the higher and exclusive sense of the term. This is then, at the same time, The Subject. The terms employed to designate them sufficiently indicate this identity: Substantive, from sub, UNDER, and stans, STANDING; and Subject, from sub, UNDER, and jectus, THROWN or CAST. These are, therefore, nearly etymological equivalents.
Before passing to the consideration of the Subject and the Proposition, let us finish with the Nouns Adjective, to which we have only given an incidental attention.
These are the representatives of Incidence or Attribution; and correspond to the entire adjectivity pertaining to the substantiality of the real or concrete Universe; both Substance and Incidence falling as parts of one domain within the larger domain of Relation, which in Language is the domain of Grammar proper, including Etymology and Syntax.
It may now be shown that this Adjective World is so much a world by itself that Kant's namings for the four groups of the Categories of the Understanding, which we are here enlarging to be the Categories of All Being, are precisely the most appropriate namings for the subdivisions of the Adjective World. These are:
1. Adjectives of Quality.
2. Adjectives of Relation.
3. Adjectives of Quantity.
4. Adjectives of Mode.
1. Adjectives of Quality are those which designate the qualities of things as good or bad, etc. They are susceptible of three Degrees of Comparison; and are, without due consideration, usually regarded by Grammarians as if they constituted the whole of the Adjective World.
2. Adjectives of Relation are, as we have seen, (chiefly) the Oblique Cases of the Noun Substantive. They admit of no Degrees of Comparison. These have not heretofore been regarded as Adjectives; but broadly and philosophically considered, they are so.
3. Adjectives of Quantity are the Numerals, which always instinctively find their way among the Adjectives in the Grammar Books, without their presence there being duly accounted for, that part of speech having been usually defined as relating exclusively to the Quality of Things. These numeral Adjectives subdivide into Ordinal Numerals and Cardinal Numerals; and, like Adjectives of Relation, they are not susceptible of being varied by the Degrees of Comparison.
4. Adjectives of Mode relate to the Conditions of Existence, as necessary and unnecessary, important and unimportant, etc. They are somewhat ambiguous as to their susceptibility to comparison. It is over this class of Adjectives that the Grammarians dispute. If a thing is necessary, then, it is said, it cannot be more necessary, or most necessary, the Positive Case being itself Absolute or Superlative. In some cases this rule is not so clear, and there is doubt whether it is proper to apply the signs of Comparison or not. We may correctly say more important and most important; and on the whole the Adjectives of Mode, or Modal Adjectives, are to be classed as capable of Comparison.