CHAPTER II 

 THE VALIDITY OF SCIENTIFIC RECONSTRUCTION 



i. So far we have sought to meet the objections which can 

 be brought against the view that rational thought yields 

 genuine knowledge of Reality so far as its sphere extends. 

 If our arguments are sound it may do so. But can we 

 know that it actually does so ? If the negative arguments 

 are overcome, what positive arguments can be used ? This 

 is to enquire into the grounds of validity, and we must 

 follow this enquiry to the point at which we can apprehend 

 the central conception involved. The question is how a 

 partial experience can be the valid basis of a knowledge 

 which extends indefinitely beyond it. The question 

 becomes the more urgent in proportion as we recognise 

 how narrow are the limits of experience strictly defined. 

 For your experience is not mine, nor mine yours, and in 

 utilising the experience of others we are already commit- 

 ting ourselves to a system of inferences and implications 

 as to the credibility of testimony and so forth, to face which 

 is to realise that any such expression as the experience of 

 the race may be a convenient and compact form of expres- 

 sion, but does not stand for anything that is pure experience 

 denuded of inferential assumptions. If experience is the 

 only trustworthy basis of knowledge, it must be under- 

 stood that for any one of us it is ultimately his own experi- 

 ence that is meant. But, furthermore, his experience comes 

 to him as a constantly moving stream of change, passing 

 away and partly forgotten as it goes. His knowledge of 

 the past, to say nothing of the future, is at any moment 

 a thought, a judgment that goes beyond the experience of 



