A System of Logic: Ratiocinative and Inductive, 7th Edition, Vol. I
John Stuart Mill · en
Conformably to these views, almost all the writers on Logic in the last
two centuries, whether English, German, or French, have made their
theory of Propositions, from one end to the other, a theory of
Judgments. They considered a Proposition, or a Judgment, for they used
the two words indiscriminately, to consist in affirming or denying one
_idea_ of another. To judge, was to put two ideas together, or to bring
one idea under another, or to compare two ideas, or to perceive the
agreement or disagreement between two ideas: and the whole doctrine of
Propositions, together with the theory of Reasoning, (always necessarily
founded on the theory of Propositions,) was stated as if Ideas, or
Conceptions, or whatever other term the writer preferred as a name for
mental representations generally, constituted essentially the subject
matter and substance of those operations.
It is, of course, true, that in any case of judgment, as for instance
when we judge that gold is yellow, a process takes place in our minds,
of which some one or other of these theories is a partially correct
account. We must have the idea of gold and the idea of yellow, and these
two ideas must be brought together in our mind. But in the first place,
it is evident that this is only a part of what takes place; for we may
put two ideas together without any act of belief; as when we merely
imagine something, such as a golden mountain; or when we actually
disbelieve: for in order even to disbelieve that Mahomet was an apostle
of God, we must put the idea of Mahomet and that of an apostle of God
together. To determine what it is that happens in the case of assent or
dissent besides putting two ideas together, is one of the most intricate
of metaphysical problems. But whatever the solution may be, we may
venture to assert that it can have nothing whatever to do with the
import of propositions; for this reason, that propositions (except
sometimes when the mind itself is the subject treated of) are not
assertions respecting our ideas of things, but assertions respecting the
things themselves. In order to believe that gold is yellow, I must,
indeed, have the idea of gold, and the idea of yellow, and something
having reference to those ideas must take place in my mind; but my
belief has not reference to the ideas, it has reference to the things.
What I believe, is a fact relating to the outward thing, gold, and to
the impression made by that outward thing upon the human organs; not a
fact relating to my conception of gold, which would be a fact in my
mental history, not a fact of external nature. It is true, that in order
to believe this fact in external nature, another fact must take place in
my mind, a process must be performed upon my ideas; but so it must in
everything else that I do. I cannot dig the ground unless I have the
idea of the ground, and of a spade, and of all the other things I am
operating upon, and unless I put those ideas together.[17] But it would