SCIENCE AND REVOLUTION 



formula. And in attempting to find the value of 

 the unknown quantities of any algebraic formula 

 I must rely on the known quantities for a solu- 

 tion of the problem. And frequently it is found 

 in the process of the solution that one or all of 

 the unknown quantities are equal to zero. It is 

 not at all improbable that in solving the equation 

 of man and his environment I may find that the 

 so-called mind and soul, as currently conceived, 

 spell zero. 



At all events, in the attempt of solving my 

 equation of man and his environment I must 

 operate with the quantities which are known. 

 And if I use the terms mind and soul occasionally 

 I refer to them simply as brain activities, identi- 

 cal so far as our discussion is concerned with 

 any other brain activity connected with thought. 

 Whether mind and soul are anything else but 

 brain activities we shall be better able to tell 

 at the end of our journey. 



* * * # # 



III. THE AWAKENING OF PHILOSOPHY 



With man's material brain for a starting point 

 we now set out on our discussion of the evolu- 

 tion of theories of evolution. 



14 



