Mental Discipline in Education. 439 



from objective realities to their ideal symbols. We here, 

 as it were, take one step away from outward nature and 

 enter a world of representation, which is of great impor- 

 tance to us because of the still greater importance of that 

 which it represents. The overlooking of this fact has 

 been the error of ages. Men have been fascinated with 

 the curious phenomenon of mental representation, and have 

 dwelt upon it in utter neglect of that which is represented. 

 Confessedly of high interest, they have forgotten that it is 

 forever subordinate to the original order for which it 

 stands. Losing themselves in the contemplation of this 

 mystery, metaphysicians have often fallen into a kind of 

 sceptical hallucination as to whether, after all, there are 

 any realities back of the ideas ; or, granting an external 

 world, they have held it to be of very trifling account, as 

 all its truths are to be excogitated from the realm of pure 

 ideas. Modern psychology inverts this order, and teaches 

 not only that a knowledge of Nature depends upon the 

 direct study of Nature, but that our knowledge of mind it- 

 self, of the relations among ideas, depends upon our prior 

 understanding of the relations of phenomena and of the 

 laws of action in the environment. It was this danger of 

 being beguiled with mere symbols that called forth the 

 sagacious adjuration of Newton, "Oh, physics, beware of 

 metaphysics ! " Mr. Mill thus points out the mischievous 

 consequences of the error in the case of logic : 



The notion that what is of primary importance to the logician in 

 a proposition, is the relation between the two ideas corresponding to 

 the subject and predicate (instead of the relation between the two 

 phenomena which they respectively express), seems to me one of the 

 most fatal errors ever introduced into the philosophy of logic, and 

 the principal cause why the theory of the science has made such 

 inconsiderable progress during the last two centuries. The treatises 

 on logic, and on the branches of mental philosophy connected with 

 logic, which have been produced since the intrusion of this cardinal 

 error, though sometimes written by men of extraordinary abilities and 



