276 REASONING. 



discovered relations, comes only by degrees. So long as it is 

 not thoroughly formed, no necessary character is ascribed to 

 the new truth. But in time, the philosopher attains a state of 

 mind in which his mental picture of nature spontaneously re- 

 presents to him all the phenomena with which the new theory 

 is concerned, in the exact light in which the theory regards 

 them : all images or conceptions derived from any other theory, 

 or from the confused view of the facts which is anterior to any 

 theory, having entirely disappeared from his mind. The mode 

 of representing facts which results from the theory, has now 

 become, to his faculties, the only natural mode of conceiving 

 them. It is a known truth, that a prolonged habit of arrang- 

 ing phenomena in certain groups, and explaining them by 

 means of certain principles, makes any other arrangement or 

 explanation of these facts be felt as unnatural : and it may at 

 last become as difficult to him to represent the facts to himself 

 in any other mode, as it often was, originally, to represent 

 them in that mode. 



But, farther, if the theory is true, as we are supposing it to 

 be, any other mode in which he tries, or in which lie was for- 

 merly accustomed, to represent the phenomena, will be seen 

 by him to be inconsistent with the facts that suggested the new 

 theory facts which now form a part of his mental picture of 

 nature. And since a contradiction is always inconceivable, his 

 imagination rejects these false theories, and declares itself in- 

 capable of conceiving them. Their inconceivableness to him 

 does not, however, result from anything in the theories them- 

 selves, intrinsically and a priori repugnant to the human 

 faculties ; it results from the repugnance between them and a 

 portion of the facts ; which facts as long as he did not know, 

 or did not distinctly realize in his mental representations, the 

 false theory did not appear other than conceivable ; it becomes 

 inconceivable, merely from the fact that contradictory elements 

 cannot be combined in the same conception. Although, then, 

 his real reason for rejecting theories at variance with the true 

 one, is no other than that they clash with his experience, he 

 easily falls into the belief, that he rejects them because they 

 are inconceivable, and that he adopts the true theory because 



