{169} We now arrive at a very important conclusion; for it thus
appears, that all Predication, is Predication of Genus or Species,
since the Attributives classed under the titles of _Differentia_,
_Proprium_, _Accidens_, cannot be used but as part of the name of a
Species. But we have seen, above, that Predication by Genus and
Species is merely the substitution of one name for another, the more
general for the less general; the fact of the substitution being
marked by the _Copula_. It follows, if all Predication is by Genus
and Species, that all Predication is the substitution of one name
for another, the more for the less general.
It will be easy for the learner to make this material fact familiar
to himself, by attending to a few instances. Thus, when it is said
that man is rational, the term rational is evidently elliptical, and
the word animal is understood. The word rational, according to
grammatical language, is an adjective, and is significant only in
conjunction with a substantive. According to logical language, it is
a connotative term, and is without a meaning when disjoined from the
object, the property or properties of which it connotes.[51]
[Editor's footnote 51: I am unable to feel the force of this remark.
Every predication ascribes an attribute to a subject. Differentiae,
Propria, and Accidents, agree with generic and specific names in
expressing attributes, and the attributes they express are the whole
of their meaning. I therefore cannot see why there should not be
Predication of any of these, as well as of Genus and Species. These
three Predicables, the author says, cannot be used but as part of
the name of a genus or species: they are adjectives, and cannot be
employed without a substantive understood. Allowing this to be
logically, as it is grammatically, true, still the comprehensive and
almost insignificant substantive, "thing" or "being," fully answers
the purpose; and the entire meaning of the predication is contained
in the adjective. These adjectives, as the author remarks, are
connotative terms; but so, on his own shewing elsewhere, are all
concrete substantives, except proper names. Why, when it is said
that man is rational, must "the word animal" be "understood?"
Nothing is understood but that the being, Man, has the attribute of
reason. If we say, God is rational, is animal understood? It was
only the Greeks who classed their gods as [Greek: zô=a a)tha/nata].