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PREFACE 



Natural Science falls into two parts, doctrine and 

 research. The doctrine consists of dogmatic assertions, 

 which contain a definite statement concerning Nature. 

 The form these assertions take often suggests that they 

 are based on the authority of Nature herself. 



This is a mistake, for Nature imparts no doctrines : 

 she merely exhibits changes in her phenomena. We 

 may so employ these changes that they appear as 

 answers to our questions. If we are to get a right 

 understanding of the position of science vis-a-vis of 

 Nature, we must transform each of the statements into 

 a question, and account to ourselves for the changes in 

 natural phenomena which men of science have used as 

 evidence for their answer. 



Investigation cannot proceed otherwise than by 

 making a supposition (hypothesis) in its question, a 

 supposition in which the answer (thesis) is already 

 implicit. The ultimate recognition of the answer and 

 the setting up of a doctrine follow as soon as the 

 investigator has discovered in Nature what he considers 

 a sufficient number of phenomena that he can interpret 

 as positive or negative on the lines of his hypothesis. 



The sole authority for a doctrine is not Nature, but 

 the investigator, who has himself answered his own 

 question. 



A man may have assimilated the conclusions of 



natural science in the form of doctrine, and may know 



how to employ them in speculation, according to the 



rules of logic ; but he still knows nothing whatsoever 



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