Mental Discipline in 1 -'.due at ion. 425 



deductive reasoning the same as mathematics, but of a still 

 more valuable character. For while mathematics deals 

 with the smallest number of ideas, those of space and num- 

 ber, which may be abstracted entirely from all material ex- 

 istence, physics includes, in addition to these, the concep- 

 tions of matter and force, although it deals with them in 

 their universal properties and forms; and it thus comes 

 nearer to the realities of experience. Deduction is the 

 most common and practical form of mental activity. We 

 are constantly reasoning from our general notions or opin- 

 ions to particular facts and circumstances. Induction lays 

 the mental foundation by showing us how correctly to ar- 

 rive at these general notions; deduction guides their con- 

 stant application ; the physical sciences afford the best 

 training-ground for both. 



The mental advantages to be derived from a more thor- 

 ough study of the physical sciences have been very clearly 

 and impressively presented in a late discourse by Mr. John 

 Stuart Mill,* and his view so strongly confirms the present 

 argument as to justify extended quotation : 



The most obvious part of the value of scientific instruction, the 

 mere information that it gives, speaks for itself. We are born into 

 a world which we have not made ; a world whose phenomena take 

 place according to fixed laws, of which we do not bring any knowl- 

 edge into the world with us. In such a world we are appointed to 

 live, and in it all our work is to be clone. Our whole working power 

 depends on knowing the laws of the world in other words, the 

 properties of the things which we have to work with, and to work 

 among, and to work upon. We may and do rely, for the greater 

 part of this knowledge, on the few who in each department make 

 its acquisition their main business in life. But unless an elementary 

 knowledge of scientific truths is diffused among the puhlic, they 

 never know what is certain and what is not, or who are entitled to 



* Inaugural address delivered to the University of St. Andrew, Febru- 

 ary i, 1867. By John Stuart Mill. 

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