"92 OPERATIONS SUBSIDARY TO INDUCTION. 



wise than by way. of comparison and abstraction, and, in the most 

 important and the most numerous cases are evolved by abstraction 

 from the very phenomena which it is their office to colligate. I am far 

 from wishing to imply that it is not often a very difficult thing to per- 

 form this process of abstraction well, or that the success of an induc- 

 tive operation does not, in many cases, principally depend upon the 

 skill with which we perform it. Bacon, in his forcible manner, desig- 

 nated as one of the principal obstacles to good induction, general con- 

 ceptions wrongly formed, " notiones temere a rebus abstractas:" to 

 which Mr. Whewoll adds, that not only does bad abstraction make bad 

 induction, but that in order to perform induction well, we must have 

 abstracted well : our general conceptions must be " clear" and " appro- 

 priate" to the matter in hand. Nor can it be doubted that, in what 

 they thus said, both Bacon and Mr. Whewell, though they expressed 

 their meaning vaguely, had a meaning, and a highly important one. 



§ 3. In attempting to show what the difficulty in this matter really 

 is, and how it is surmounted, I must beg the reader, once for all, to 

 bear this in mind : That although in discussing Mr, Whewell's opin- 

 ions I am willing to adopt his language, and to speak, therefore, of 

 connecting facts through the instrumentality of a conception, this tech- 

 nical phraseology means neither more nor less than what is commonly 

 called comparing the facts with one another and determining in what 

 they agree. Nor has the technical expression even the advantage of 

 being metaphysically correct. The facts are not connected; they 

 remain separate facts as they were before. The ideas of the facts may 

 become connected, that is, we may be led to think of them together; 

 but this consequence is no more than what may be produced by any 

 casual association. What really takes place, is, I conceive, more phi- 

 losophically expressed by the common word Coinparison, than by the 

 phrases "to connect" or "to superinduce." For, as the general con- 

 ception is itself obtained by a comparison of particular phenomena, so, 

 when obtained, the mode in which we apply it to other phenomena is 

 again by comparison. We compare phenomena wdth each other to get 

 the conception, and we then compare those and other phenomeiia witJi 

 the conception. We get the conception of an animal (for instance) by 

 comparing different animals, and when we afterwards see a creature 

 resembling an animal, we compare it with our general conception of 

 an anin>al ; and if it agi'ees with that general conception, we include it 

 in the class. The conception becomes the type of comparison. 



And we need only consider what comparison is, to see that where 

 the objects are more than two, and still more when they are an indefi- 

 nite number, a type of some sort is an indispensable condition of the 

 comparison. When we have to an-ange and classify a great number of 

 objects according to their agreements and differences, we do not make 

 a confused attempt to compare all with all. We know that two things 

 are as much as the human mind can attend to at a time, and we there- 

 fore fix upon one of tho objects, either at hazard or because it offers in 

 a peculiarly striking manner some important character, and, taking this 

 as our standard, we compare with it one object after another. If we 

 find a second object which presents a remarkable agieement with the 

 first, inducing us to class them together, the question instantly arises, 

 in what circumstances do they agree 1 and to take notice of these cir- 



