GROUND OF INDUCTION. 



205 



fcheory of the subject has certainly 

 been exaggerated. Although (along 

 with some fundamental errors) his 

 writings contain, more or less fully 

 developed, several of the most im- 

 portant principles of the Inductive 

 Method, physical investigation has 

 now far outgrown the Baconian con- 

 ception of Induction. Moral and 

 political inquiry, indeed, are as yet 

 far behind that conception. The cur- 

 rent and improved modes of reason- 

 ing on these subjects are still of the 

 same vicious description against which 

 Bacon protested ; the method almost 

 exclusively employed by those pro- 

 fessing to treat such matters induc- 

 tively, is the very inductio per enu- 

 nierationem simplicem which he con- 

 demns ; and the experience which we 

 hear so confidently appealed to by all 

 sects, parties, and interests is still, in 

 his own emphatic words, mera palpatio. 



§ 3. In order to a better under- 

 standing of the problem which the 

 logician must solve if he would estab- 

 lish a scientific theory of Induction, 

 let us compare a few cases of incorrect 

 inductions with others which are ac- 

 knowledged to be legitimate. Some, 

 we know, which were believed for 

 centuries to be correct, were never- 

 theless incorrect. That all swans are 

 white, cannot have been a good in- 

 duction, since the conclusion has 

 turned out erroneous. The experi- 

 ence, however, on which the conclu- 

 sion rested was genuine. From the 

 earliest records, the testimony of the 

 inhabitants of the known world was 

 unanimous oii the point. The uniform 

 experience, therefore, of the inhabi- 

 tants of the known world, agreeing 

 in a common result, without one 

 known instance of deviation from 

 that result, is not always suflBcient to 

 establish a general conclusion. 



But let us now turn to an instance 

 apparently not very dissimilar to this. 

 Mankind were WTX)ng, it seems, in 

 concluding that all swans were white ; 

 are we also wrong when we conclude 

 tl^at (^1 mep's beads grow above their 



shoulders, and never below, in spite 

 of the conflicting testimony of the 

 naturalist Pliny? As there were 

 black swans, though civilised people 

 had existed for three thousand years 

 on the earth without meeting with 

 them, may there not also be "men 

 whose heads do grow beneath their 

 shoulders," notwithstanding a rather 

 less perfect unanimity of negative 

 testimony from observers ? Most 

 persons would answer No ; it was 

 more credible that a bird should vary 

 in its colour than that men should 

 vary in the relative position of their 

 principal organs. And there is no 

 doubt that in so saying they would 

 be right ; but to say why they are 

 right would be impossible, without 

 entering more deeply than is usually 

 done into the true theory of Induction. 

 Again, there are cases in which we 

 reckon with the most unfailing con- 

 fidence upon uniformity, and other 

 cases in which we do not count upon 

 it at alL In some we feel complete 

 assurance that the future will resem- 

 ble the past, the unknown be precisely 

 similar to the known. In others, 

 however invariable may be the result 

 obtained from the instances which 

 have been observed, we draw from 

 them no more than a very feeble pre- 

 sumption that the like result will hold 

 in aJl other cases. That a straight 

 line is the shortest distance between 

 two points, we do not doubt to be 

 true even in the region of the fixed 

 stars.* When a chemist announces 

 the existence and properties of a 

 newly discovered substance, if we 

 confide in his accuracy, we feel as- 

 sured that the conclusions he has 

 arrived at will hold universally, though 

 the induction be founded but on a 

 single instance. We do not withhold 

 our assent, waiting for a repetition of 

 the experiment ; or if we do, it is 

 from a doubt whether the one experi- 

 ment was properly made, not whether, 



* In strictness, wherever the present 

 constitution of space exists ; which we 

 have ample reason to believe that it does 

 in-the region of the fixed stars. 



