1 62 



REASONING. 



trary." * So long as our ideas are 

 indistinct altogether, we do not know 

 what is or is not capable of being dis- 

 tinctly conceived ; but, by the ever- 

 increasing distinctness with which 

 acientific men apprehend the general 

 conceptions of science, they in time 

 come to perceive that there are cer- 

 tain laws of nature, which, though 

 historically and as a matter of fact 

 they were learnt from experience, we 

 cannot, now that we know them, 

 distinctly conceive to be other than 

 they are. 



The account which I should give of 

 this progress of the scientific mind is 

 somewhat different. After a general 

 law of natiire has been ascertained, 

 men's minds do not at first acquire a 

 complete facility of familiarly repre- 

 senting to themselves the phenomena 

 of nature in the character which that 

 law assigns to them. The habit which 

 constitutes the scientific cast of mind, 

 that of conceiving facts of all descrip- 

 tions conformably to the laws which 

 regulate them— phenomena of all de- 

 scriptions according to the relations 

 which have been ascertained really to 

 exist between them ; this habit, in the 

 case of newly 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 con- 

 cerned, 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 repre- 

 senting facts which results from the 

 theory has now become, to his facul- 

 ties, the only natural mode of con- 

 ceiving them. It is a known truth, 

 that a prolonged habit of arranging 

 phenomena in certain groups, and 



* Phil, of Disc, p. 463. 



explaining them by means of certain 

 principles, makes any other arrange- 

 ment 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, further, (if the theory is true, 

 as we are supposing it to be,) any other 

 mode in which he tries, or in which he 

 was formerly accustomed, to represent 

 the phenomena, will be seen by him to 

 be inconsistent with the facts that sug- 

 gested the new theory — facts which 

 now form a part of his mental picture 

 of natura And since a contradiction 

 is always inconceivable, his imagina- 

 tion rejects these false theories, and 

 declares itself incapable of conceiving 

 them. Their inconceivableness to him 

 does not, however, result from anything 

 in the theories themselves intrinsically 

 and d, priori repugnant to the human 

 faculties ; it results from the repug- 

 nance between them and a portion 

 of the facts, which facts as long as 

 he did not know, or did not dis- 

 tinctly realise in his mental repre- 

 sentations, the false theory did not 

 appear other than conceivable ; it be- 

 comes inconceivable merely from the 

 fact that contradictory elements can- 

 not be combined in the same concep- 

 tion. 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 incon- 

 ceivable, and that he adopts the true 

 theory because it is self-evident, and 

 does not need the evidence of experi- 

 ence at all. 



This I take to be the real and suf- 

 ficient explanation of the paradoxical 

 truth, on which so much stress is laid 

 by Dr. Whewell, that a scientifically 

 cultivated mind is actually, in virtue 

 of that cultivation, unable to conceive 

 suppositions which a common man 

 conceives without the smallest diffi- 

 culty. For there is nothing incon- 

 ceivable in the suppositions them- 



