J34 



REASONING. 



remaining operation, which is sub- 

 stantially that of interpreting the 

 general proposition, we shall call by 

 its usual name, Deduction. And we 

 shall consider every process by which 

 anything is inferred i"especting an 

 unobserved case as consisting of an 

 Induction followed by a Deduction ; 

 because, although the process needs 

 not necessarily be carried on in this 

 form, it is always susceptible of the 

 form, and must be thrown into it 

 when assurance of scientific accuracy 

 is needed and desired. 



§8. The theory of the syllogism 

 laid down in the preceding pages has 

 obtained, among other important ad- 

 hesions, three of peculiar value ; those 

 of Sir John Herschel, * Dr. Whewell,t 

 and Mr. Bailey ; X Sir John Herschel 

 considering the doctrine, though not 

 strictly "a discovery," having been 

 anticipated by Berkeley, § 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 pre- 

 judices which iib has cast to the winds," 

 there is no cause for misgiving in the 

 fact that other thinkers, no less en- 

 titled to consideration, have formed 

 a very different estimate of it. Their 

 principal objection cannot be better 

 or more succinctly stated than by 

 borrowing a sentence from Archbishop 

 Whately. || " In every case where an 



* Review of Quetelet on Probabilities, 

 Esmya, p. 367. 



t Philosophy/ of Discovery, p. 289. 



J Theory of Reasoning, ch. iv., to which I 

 may refer for an able statement and en- 

 forcement of the ^rounds of the doctrine. 



§ On a recent careful reperusal of Ber- 

 keley's whole works, I have been unable 

 to find this doctrine in them. Sir John 

 H' rschel probably meant that it is implied 

 iTi Berkeliy's argument against abstract 

 idea-^. But I cmnot find that Berkeley 

 saw the implication, or had e^er asked 

 himself what bearing his argument had on 

 the theory of the syllocrism. Still less can 

 I admit that the doctrine is (hs has been 

 aflBrmed by one of my ablest and most 

 candid critics) "among the standing marks 

 of whnt is called the empirical pliilo80i)hy." 



I Logic, book iv. ch. 1. sect. i. 



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 judg- 

 ment that the instance or instances 

 adduced are sufficient to authorise the 

 conclusion ; that it is allowable to take 

 these instances as a sample warrant- 

 ing an inference respecting the whole 

 class ; " and the expression of this 

 judgment in words (it has been said 

 by several of my critics) w 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 cannot 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 everything we 

 do, to satisfy ourselves that it has 

 been done rightly. We conclude from 

 known instances to unknown by the 

 impulse of the generalising propensity; 

 and (until after a considerable amount 

 of practice and mental discipline) the 

 question of the sufficiency of the evi- 

 dence is only raised by a retrospective 

 act, turning back upon our own foot- 

 steps, 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 psycho- 

 logy.* We review our syllogistic as 

 well as our in,ductive processes, and 

 recognise that they have been cor- 

 rectly performed ; but logicians do 

 not add a third premise to the syllo- 

 gism, to express this act of recogni- 

 tion. A careful copyist verifies his 

 transcript by collating it with the 



♦ See the Important chapter on Belief, 

 in Professor Bain's great treatise, The Smo- 

 tiom and the Will, pp. 58i-584' 



