CHAPTER XII. RATIOCINATION.
“It would afford great light and clearness to the art
of Logic, to determine the precise nature and composition of the ideas affixed
to those words which have complex ideas; i.e.,
which excite any combinations of simple ideas, united intimately by
association.” Hartley. Prop. 12, Corol. 3.
RATIOCINATION is one of the most complicated of all
the mental phenomena. And it is worthy of notice, that more was accomplished
towards the analysis of it, at an early period in the history of intellectual
improvement, than of any other of the complex cases of human consciousness.
It was fully explained by Aristotle, that the
simplest case of Ratiocination consists of three propositions, which he called
a syllogism. A piece of ratiocination may consist of one, or more syllogisms,
to any extent; but every single step is a syllogism.
A ratiocination, then, or syllogism, is first
resolved into three propositions. The following may be taken as one of the
simplest of all examples. “All men are animals: kings are men: therefore kings
are animals.”
Next, the Proposition is resolved into its proximate
elements. These are three; two Terms, one called the Subject, the other the
Predicate, and the Copula. What is the particular nature of each of these
elements we have already seen, and here, therefore, need not stay to inquire.
The ancient writers on Logic proceeded in their
analysis, no farther than Terms. After this, they only endeavoured to enumerate
and classify terms; to enumerate and classify propositions; to enumerate and
classify syllogisms; and to give the rules for making correct syllogisms, and
detecting incorrect ones. And this, as taught by them, constituted the whole
science and art of Logic.
What, under this head, we propose to explain, is the
process of association involved in the syllogism, and in the belief which is
part of it.
That part of the process which is involved in the two
antecedent propositions, called the premises, has been already explained. It is
only, therefore, the third proposition, called the conclusion, which further
requires exposition.
We have seen, that in the proposition, “All men are
animals,” Belief is merely the recognition that the meaning of the term, “all
men,” is included in that of the term “animals,” and that the recognition is a
case of association. In the proposition also, “kings are men,” the belief is
merely the recognition, that the individuals named “kings,” are part of the
many, of whom “men,” is the common name. This has already been more than once
explained. And now, therefore, remains only to be shewn what further is
involved in the third proposition, or conclusion, “kings are animals.”
In each of the two preceding propositions, two terms
or names are compared. In the last proposition, a third name is compared with
both the other two; immediately with the one, and, through that, with the
other; the whole, obviously, a complicated case of association.
In the first proposition, “all men are animals,” the
term, “all men,” is compared with the term animals; in other words, a certain
association, already expounded, takes place. In the second proposition, “kings
are men,” the term “kings,” is compared with the term “all men;” comparison
here, again, being only a name for a particular case of association. In the
third proposition, “kings are animals,” the name “kings,” is compared with the
name “animals,” but mediately through the name, “all men.” Thus, “kings,” is
associated with “all men,” “all men,” with “animals;” “kings,” therefore, with
“animals,” by a complicated, and, at the same time, a rapid, and almost
imperceptible process. It would be easy to mark the steps of the association.
But this would be tedious, and after so much practice, the reader will be at no
loss to set them down for himself (109)
[109 This chapter, which is of a very summary
character, is a prolongation of the portion of the chapter on Belief, which
examines the case of belief in the truth of a proposition; and must stand or
fall with it. The question considered is, how, from belief in the truth of the
two premises of a syllogism, we pass into belief in the conclusion. The
exposition proceeds on the untenable theory of the import of propositions, on
which I have so often had occasion to comment. That theory, however, was not
necessary to the author for shewing how two ideas may become inseparably
associated through the inseparable association of each of them with a third
idea: and inas much as an inseparable association between the subject and
predicate, in the author’s opinion, constitutes belief, an explanation of
ratiocination conformable to that given of belief follows as a matter of
course.
Although I am unable to admit that there is nothing
in belief but an inseparable association, and although I maintain that there
may be belief without an inseparable association, I can still accept this
explanation of the formation of an association between the subject and
predicate of the conclusion, which, when close and intense, has, as we have seen,
a strong tendency to generate belief. But to shew what it is that gives the
belief its validity, we must fall back on logical laws, the laws of evidence.
And independently of the question of validity, we shall find in the reliance on
those laws, so far as they are understood, the source and origin of all
beliefs, whether well or ill-founded, which are not the almost mechanical or
automatic products of a strong association of the lively suggestion of an idea.
We may therefore pass at once to the nature of Evidence, which is the subject
of the next chapter.
I venture to refer, in passing, to those chapters in
my System of Logic, in which I have maintained, contrary to what is laid down
in this chapter, that Ratiocination does not consist of Syllogisms; that the
Syllogism is not the analysis of what the mind does in reasoning, but merely a
useful formula into which it can translate its reasonings, gaining thereby a
great increase in the security for their correctness. Ed.]
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