48 INTRODUCTION TO SCIENCE 



In the end he found it necessary to bring in elec- 

 tricity as well. But who shall call this failure? !> 

 We understand, however, why Kelvin himself, 

 actuated by the desire to reduce all physical 

 phenomena within the duality of matter and 

 energy an ideally scientific desire should con- 

 fess in this respect to failure. 



In connection with the reduction of natural 

 processes to simpler terms, we must be careful 

 not to allow the idea to become tyrannical. It 

 is not always possible to effect a reduction, and 

 it is not always relevant. Moreover, it is not 

 always easy to make sure that the reduction is 

 complete; some residual phenomena may escape 

 which are at the very heart of the matter. 



We cannot describe thinking in physiological 

 terms, still less in physical terms. By psycho- 

 logical analysis we may perhaps make it more 

 intelligible, but not otherwise. That is to say, 

 we cannot bring it under any general biological 

 or physical concept. And although we are sure 

 that a thinking man developed in time out of a 

 fertilized egg-cell, we cannot reduce the activities 

 of the thinking man to what we know of the activ- 

 ities of the cell. And, again, as we shall explain 

 more fully in the section on "particular aims," 

 even if a physico-chemical reduction were effected 

 of all that goes on in the cell, that would not give 

 us a useful biological account of its behaviour, 



