20 THE PRESIDENTIAL ADDRESS. 



our experimental work ; and as long as it does so we avail ourselves of it, 

 necessarily and witli right. But just as in the case of research into the 

 properties of radiation we use a corpuscular theory or a wave theory 

 according to the needs of the moment, the two theories being actually 

 incompatible to our minds in their present development, so the use of a 

 mechanistic theory in the laboratory does not imply that it represents all 

 that the human mind can use or grasp on other occasions, in present or in 

 future times. 



The proper employment of scientific research is so necessary to our 

 welfare that we cannot afford to allow misconceptions to hinder it ; and 

 the worst of all are those which would suppose it to contradict the highest 

 aims. Science, as a young friend said to me not long ago, is not setting 

 forth to destroy the soul of the nation, but to keep body and soul together. 



And some perhaps might say that in considering science in relation to 

 craftsmanship I am pressing the less noble view ; that I am not con- 

 sidering knowledge as its own end. It is said that uselessness in science 

 is a virtue. The accusation is a little obscure because it may justly be 

 said that knowledge is never useless. If I have thought of science in 

 relation to craftsmanship it is because I have tried to set out the vast 

 importance of what craftsmanship means and stands for. I have not 

 forgotten that there are other aspects of the inquiry into the truths of 

 Nature. Indeed, I could not carry out the lesser task without con- 

 sidering the whole meaning of science. And no clear line can be drawn 

 between pure science and applied science : they are but two stages of 

 development, two phases which melt into one another, and either loses 

 virtue if dissociated from the other. The dual relation is common to 

 many human activities and has been expressed in many ways. Long ago 

 it was said in terms which in their comprehensiveness include all the 

 aspirations of the searcher after knowledge : ' Thou shalt love the Lord 

 thy God with all thy heart and with all thy soul and with all thy strength ' ; 

 and ' Thou shalt love thy neighbour as thyself.' In the old story every 

 listener, from whatever country he came, Parthians and Medes, Cretans 

 and Arabians, heard the message in his own tongue. A great saying 

 speaks to every man in the language which he understands. To the 

 student of science the words mean that he is to put his whole heart into 

 his work, believing that in some way which he cannot fully comprehend 

 it is all worth while, and that every straining to understand his surround- 

 ings is right and good ; and, further, that in that way he can learn to be 

 of use to his fellow-men. 



