532 Edward Livingston Youmans. 



and dissolution of things in the onward course of Nature, 

 was elaborately presented in First. Principles, and might 

 have been there left to take its place and its chance 

 among philosophical theories. But it had not been ex- 

 ploited by Mr. Spencer in the way of mental gymnastics, as 

 a piece of novel and ingenious speculation. He believed 

 it to embody a living and applicable principle of the great- 

 est moment. If the law of Evolution be true, it is a truth 

 of transcendent import, no less in the sphere of practical 

 life than in the world of thought, and it was important that 

 it should be carried out in the various fields of its applica- 

 tion. Moreover, Mr. Spencer had been drawn to the inves- 

 tigation by his interest in the study of human affairs, and 

 his task was but fairly begun with the establishment of the 

 principle by which they are to be interpreted. In the strict 

 logical order the next step would have been to trace the 

 operation of the law in the inorganic or pre-organic world, but 

 the vastness of the subject forbade this, and Mr. Spencer 

 found it necessary to enter at once upon the organic divi- 

 sion of his scheme. In the Principles of Biology the sub- 

 ject of life was accordingly comprehensively dealt with 

 from the Evolution point of view. He then passed to the 

 phenomena of mind, and recast and amplified the Principles 

 of Psychology in accordance with his more matured opin- 

 ions, placing it upon the ampler basis afforded by First 

 Principles and the Principles of Biology. These three 

 works, forming five volumes of the System of Philosophy, 

 are now published, and they carry him half through the 

 undertaking the Principles of Sociology, in three volumes, 

 and the Principles of Morality, in two volumes, remaining 

 yet to be written. Mr. Spencer allowed twenty years for 

 the whole enterprise; ill health and unforeseen interrup- 

 tions have occasioned considerable delay, and it was half 

 accomplished in twelve years. 



A further illustration of the comprehensive and thor- 



