156 DEVELOPMENT AND PURPOSE CHAP. 



and a wider reality of which that mind is a part and with 

 which it is in contact. We see next that any thought 

 which we can justly call knowledge is supposed thereby 

 to be an accurate assertion of such reality, and that if this 

 supposition is ever justified, it implies that the mind 

 operates somehow so as to correspond with reality. It is 

 clear that such operation is only one of many possibilities, 

 and among other things the questions, how it has come 

 about and to what extent it has come about, are distinct 

 but related questions affecting the whole interpretation of 

 that which we take for knowledge. We have to recognise 

 that the most complete and consistent thought attainable 

 by any mind will contain only so much truth as the 

 measure of that mind permits, which may be anything 

 from zero upwards. Truth itself is not relative, but the 

 truest judgment we are capable of making is related, in 

 strict proportion, to the structure of our minds. Our 

 attitude to our own apparent knowledge becomes not so 

 much one of assured confidence as one of effort and con- 

 scious imperfection. Our most fundamental conceptions 

 become ways of apprehending reality or of co-ordinating 

 experiences that have lost all sacrosanct immutability and 

 may require revision and supplementation like everything 

 else that belongs to growth. The structural principles of 

 thought are conceived not as rigid moulds into which all 

 truth must fit, but rather as plastic elements of a growing 

 structure which may be modified without loss of identity 

 to take a wider and fuller experience within their 

 grasp. 



3. Thus, on the one hand, the realisation of the subjec- 

 tive factor in knowledge leads to the conception of a mind- 

 structure with a life history of its own, a conception which 

 gives shape to the modern investigation of personal and 

 social psychology. On the other, it engenders the logic 

 of experience. It demanded some form of mental opera- 

 tion in which an objective element could be securely pre- 

 dicated. Of such a form immediate experience seemed to 

 be the clearest case, and experience has been the term round 

 which the controversies of philosophy have raged. For 



