CONDITIONS OF DEVELOPMENT. 243 



beginning its existence as a ''tabula rasa." The 

 mind truly began its existence as a blank sheet, but 

 that was in the very first of the whole series of 

 living organisms, and by the inherited results of the 

 experience of every succeeding generation it has 

 attained its present development. It is not within 

 the scope of the present work to explain in how far 

 mental phenomena are due to properties of some 

 mode of Being, and how far they are the result of 

 processes of development. It is enough to say that 

 all material form and activity (as of brain and nerves) 

 come under the latter category. Professor Hoffding ^ 

 has pointed out in an admirable manner the paral- 

 lelism existing between the material and mental — 

 the body and mind. 



The history of philosophy and of nations shows 

 how the development of knowledge and institutions 

 has followed the general principles of the theory 

 of development here set forth. For while the 

 material world has remained unchanged, each suc- 

 cessive generation of mankind has been altered 

 by the slowly accumulating mass of human experi- 

 ence, and so has reacted to the demands of envi- 

 ronment in a slightly different manner. The great 

 minds who have added to human knowledge have 

 but reacted in a natural way to the influence of 



1 Outlines of Psychology. Macmillan & Co, 



