The Material of Selective Thinking 239 



(how certain variations are singled out for survival) ; 3. the 

 criteria of selection (what variations are singled out for 

 survival) ; 4. certain resulting interpretations. 



§ I. The Material of Selective Thinking 



I suppose that every one will admit that the growth of 

 the mind depends upon the constant reception of new ma- 

 terials — materials which do not repeat former experiences 

 simply, but constitute in some sense 'variations' upon 

 them. This is so uniform an assumption and so constant 

 a fact that it is not necessary to enlarge upon it, at least so 

 far as the growth of our empirical systems of knowledge 

 is concerned. But besides the constantly enlarging and 

 varying actual experiences of the world of persons and 

 things, we have in the imaging functions, taken as a 

 whole, a theatre in which seeming novelties of various sorts 

 are constantly disporting themselves. Seeing further 

 that it is the function of memory, strictly defined, to be 

 true to the past, to have for its ideal the reproduction of 

 experience without variation, it would seem to be to the 

 more capricious exercise of the imaging function which 

 usually goes by the term 'imagination ' that we are to look 

 for those variations in our thought contents which are not 

 immediately forced upon us by the concrete events of the 

 real world. 



A closer approach may be made, however, to the actual 

 sources of supply of variations in our thought contents, by 

 taking a bird's-eye view of the progress of thought looked 

 at retrospectively ; somewhat as the paleontologist puts 

 his fossils in rows and so discovers the more or less con- 

 sistent trend shown by this line of evolution or by that. 



