XVlll 



INTRODUCTION. 



M*M 



conscious of passing into an entirely new order of things. In the former 

 .we have airy and fanciful constructions, in which ima g ination along 

 'supplies the foundation, and in which facts, if introduced at all, are 

 introduced merely as ornamental additions, in no wise essential to the 

 fabric. In the latter the positions have been inverted. What was the 

 ornament has become the foundation ; what was foundation has been 

 converted into ornament. It may, indeed, be that sometimes these new 

 foundations are but slight and weak in comparison with the structure 

 they are made to support, but they are at any rate substantial, and of 

 the right material. "Jamais," says Cuvier,' speaking of his great pre- 

 decessor, "jamais il ne pose une r^gle d priori;" and even if we allow, 

 as perhaps we must, that exceptional cases may be found in which this 

 too general statement hardly holds good, and in which Aristotle seems 

 to lapse into the faulty methods of earlier writers, yet it must at the 

 same time be conceded that these occasions are at most but rare ; and 

 that when they do occur, it is because, as with other men so with 

 Aristotle, practice falls somewhat short of principle. Neither should 

 we forget that in most minds there exists an aesthetic craving after 

 /completeness, or, when this is not to be had, after its s embla nce, a 

 j craving which leads men almost irresistibly to fill up the gaps in their 

 ^stems with such makeshifts as come to hand ; and this weakness may 

 be forgiven them, if only they are ready to pull down their stop-gaps 

 and cart them to the rubbish-heap, so soon as better materials can be 

 obtained. That Aristotle, who manifestly felt this desire most acutely, 

 and who in those early days of science had but scanty means of giving 

 it legitimate satisfaction, should occasionally have had recourse to this 

 palliative, can scarcely be a matter of surprise. But how ready he was 

 to abandon it for better things the following passage, amongst others, 

 shows. " Such," he says, after speaking of the reproduction of bees, 

 " such is the conclusion to which we are led d priori, and facts appa- 

 rently support it. I say apparently, for the actual facts are not yet 

 sufficiently made out. Should future research ever discover them, we 

 must surrender ourselves to their guidance, rather than to that of theory; 

 and theories must be abandoned unless their teachings tally with the 

 indisputable results of observation" (De Gener. iii. 10,25). It was by 

 /thus altering the basis of enquiry, and substituting facts for theories, 

 '^' more than by actual observations, that Aristotle made a huge step in 

 advance of his biological predecessors. And if, some two thousand 

 years later, Bacon gained for himself an immortal name by insisting 

 still more peremptorily upon the value of induction, it must be remem- 



' "Toutes les propositions generales, qu'il exprime, sont des inductions, resultant de 

 I'observation et de la comparaison des fails particuliers ; jamais il ne pose une regie 

 i priffri."—IiisL d. Sc. Nat. i. 143. 



