CONTRARIETY OF OPINION. 153 



by every one, few prejudices of sense can arise re- 

 specting them. But when we proceed further, and 

 attempt, from these facts, to draw inferences, the 

 case is different. No principles having been yet 

 established, by which the facts we know from ex- 

 perience can be generalised in such a way as to es- 

 tablish their mutual relation and dependence. Every 

 naturalist therefore thinks he is at liberty to draw his 

 own inferences, and to apply them to the systematic 

 arrangement of the objects by which they are fur- 

 nished. One, for instance, arguing from the flight 

 of the bat, looks on it as that animal which constitutes 

 the true passage from quadrupeds to birds. Another, 

 looking to its general aspect, is disposed to place it 

 among the mice, fortified by the general name given 

 by the French to the whole tribe of chauve souris. 

 A third, chiefly influenced by the peculiarity of its 

 teeth, arranges it in the same group as the monkeys : 

 and each, acting upon his respective inferences, 

 fashions his system accordingly. Now, as to the 

 facts connected with the individual structure and 

 the economy of the bat, all these naturalists would 

 agree ; because such facts can be verified by 

 their personal observation, and there would be no 

 room for prejudice. But here unanimity ceases. 

 They proceed to inferences ; and each, laying a 

 peculiar stress upon some one fact more than upon 

 others, makes it a principle of his own arrangement. 

 This is the true cause of the number and the muta- 

 bility of zoological systems. In respect to the bat, 

 it is very clear, that if there is an order or progression 

 in nature, — which no one ever thinks of doubting, — 

 this quadruped can hold but one station in the scale 



