+52 POPULAR SCIENCE MONTHLY. 



not be greatly troubled if lie rinds his powers for work as much at 

 his command as they were before. 



The modern student has heard so many versions of the story of 

 the two-faced shield that he is much disposed to suspect that many 

 of the questions which have so long divided " philosophers " may 

 be only new illustrations of the old fable, and he asks whether there 

 need be any real antagonism between those who attribute knowledge 

 to experience and those who attribute it to our innate reason. 



There are men of science who, seeing no good reason to challenge 

 Plato's belief that experience, creating nothing, only calls forth the 

 " ideas " which were already dormant or latent in the mind, do never- 

 theless find reason to ask whether exhaustive knowledge of our 

 physical history may not some time show how these dormant " ideas " 

 came to be what they are. They ask whether errors may not be judg- 

 ments which lead us into danger and tend to our physical destruction, 

 and whether it may not be because a judgment has, in the long run, 

 proved preservative in the struggle for existence that we call it true. 

 May not, for example, the difference between the error that the 

 stick half in water is bent and the truth that the stick in air is 

 straight, some time prove to be that the savage who has rectified his 

 judgment has speared his fish, while he who has not has lost his 

 dinner? 



So long as we can ask such questions as this, how can we be sure 

 that because a judgment is no more than might have been expected 

 from us, as Nature has made us, at our present intellectual level, it 

 is either necessary or ultimate or universal? Things that are innate 

 or natural are not always necessary or universal, for while reason is 

 natural to the mind of man, some men are unreasonable, and a few 

 have been even known to be illogical. 



It therefore seems clear that another view of the groundwork of 

 science than that set forth by Professor Mivart is possible, for many 

 believe that this groundwork is to be found in our desire to know 

 what we do not yet know, rather than in things known; and they be- 

 lieve they wish to know in order that they may learn to distinguish 

 truth from error, and walk with sure feet where the ignorant grope 

 and stumble. 



Many books are profitable and instructive even if they fail to con- 

 vince; and the question which a prospective student of Mivart's book 

 is likely to ask is whether it is consistent with itself; for if the 

 author has not so far made himself master of his subject as to state 

 his case without palpable contradiction, no one will expect much 

 help from him. It is a remark of Aristotle, in the Introduction to 

 the Parts of Animals, that while one may need special training to 

 tell whether an author has proved his point, all may judge whether 



