§ 8. The theory of the syllogism laid down in the preceding pages, has
obtained, among other important adhesions, three of peculiar value: those
of Sir John Herschel,(59) Dr. Whewell,(60) and Mr. Bailey;(61) Sir John
Herschel considering the doctrine, though not strictly “a discovery,”
having been anticipated by Berkeley,(62) to be “one of the greatest steps
which have yet been made in the philosophy of Logic.” “When we consider”
(to quote the further words of the same authority) “the inveteracy of the
habits and prejudices which it has cast to the winds,” there is no cause
for misgiving in the fact that other thinkers, no less entitled to
consideration, have formed a very different estimate of it. Their
principal objection can not be better or more succinctly stated than by
borrowing a sentence from Archbishop Whately.(63) “In every case where an
inference is drawn from Induction (unless that name is to be given to a
mere random guess without any grounds at all) we must form a judgment that
the instance or instances adduced are _sufficient_ to authorize the
conclusion; that it is _allowable_ to take these instances as a sample
warranting an inference respecting the whole class;” and the expression of
this judgment in words (it has been said by several of my critics) _is_
the major premise.
I quite admit that the major is an affirmation of the sufficiency of the
evidence on which the conclusion rests. That it is so, is the very essence
of my own theory. And whoever admits that the major premise is _only_
this, adopts the theory in its essentials.
But I can not concede that this recognition of the sufficiency of the
evidence—that is, of the correctness of the induction—is a part of the
induction itself; unless we ought to say that it is a part of every thing
we do, to satisfy ourselves that it has been done rightly. We conclude
from known instances to unknown by the impulse of the generalizing
propensity; and (until after a considerable amount of practice and mental
discipline) the question of the sufficiency of the evidence is only raised
by a retrospective act, turning back upon our own footsteps, and examining
whether we were warranted in doing what we have provisionally done. To
speak of this reflex operation as part of the original one, requiring to
be expressed in words in order that the verbal formula may correctly
represent the psychological process, appears to me false psychology.(64)
We review our syllogistic as well as our inductive processes, and
recognize that they have been correctly performed; but logicians do not
add a third premise to the syllogism, to express this act of recognition.
A careful copyist verifies his transcript by collating it with the
original; and if no error appears, he recognizes that the transcript has
been correctly made. But we do not call the examination of the copy a part
of the act of copying.