THE ART OF SCIENTIFIC INVESTIGATION 



becomes aware of the problem by asking why or how some 

 process works, or something takes the form that it does. That 

 a question is a stimulus is demonstrated by the fact that when 

 someone asks a question it requires an effort to restrain oneself 

 from responding. 



Some purists contend that scientists should wonder " how " 

 and not " why ". They consider that to ask " why " implies that 

 there is an intelligent purpose behind the design of things and 

 that activities are directed by a supernatural agency toward 

 certain aims. This is the teleological view and is rejected by 

 present-day science, which strives to understand the mechanism 

 of all natural phenomena. Von Bruecke once remarked : 



" Teleology is a lady without whom no biologist can live; yet 

 he is ashamed to show himself in public with her." 



In biology, asking " why " is justified because all events have 

 causes; and because structures and reactions usually fulfil some 

 function which has survival value for the organism, and in that 

 sense they have a purpose. Asking " why " is a useful stimulus 

 towards imagining what the cause or purpose may be. " How " 

 is also a useful question in provoking thought about the 

 mechanism of a process. 



There is no satisfying the scientists' curiosity, for with each 

 advance, as Pavlov said, " we reach a higher level from which 

 a wider field of vision is open to us, and from which we see 

 events previously out of range." It may be appropriate to give 

 here an illustration of how curiosity led John Hunter to carry 

 out an experiment which led to an important finding. 



While in Richmond Park one day Hunter saw a deer with 

 growing antlers. He wondered what would happen if the blood 

 supply were shut off on one side of the head. He carried out 

 the experiment of tying the external carotid artery on one side, 

 whereupon the corresponding antler lost its warmth and ceased 

 to grow. But after a while the horn became warm again and 

 grew. Hunter ascertained that his ligature still held, but neigh- 

 bouring arteries had increased in size till they carried an adequate 

 supply of blood. The existence of collateral circulation and the 

 possibility of its increasing were thus discovered. Hitherto no 

 one had dared to treat aneurism by ligation for fear of gangrene, 

 but now Hunter saw the possibilities and tried ligation in the 



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