THE ART OF SCIENTIFIC INVESTIGATION 



If these discoveries were made by chance or accident alone, 

 as many discoveries of this type would be made by any 

 inexperienced scientist starting to dabble in research as by 

 Bernard or Pasteur. The truth of the matter lies in Pasteur's 

 famous saying : "In the field of observation, chance favours 

 only the prepared mind." It is the interpretation of the chance 

 observation which counts. The role of chance is merely to 

 provide the opportunity and the scientist has to recognise it and 

 grasp it. 



Recognising chance opportunities 



In reading of scientific discoveries one is sometimes struck 

 by the simple and apparently easy observations which have given 

 rise to great and far-reaching discoveries making scientists 

 famous. But in retrospect we see the discovery with its significance 

 established. Originally the discovery usually has no intrinsic 

 significance; the discoverer gives it significance by relating it 

 to other knowledge, and perhaps by using it to derive further 

 knowledge. The difficulties in the way of making discoveries 

 in which chance is involved may be discussed under the following 

 headings. 



(a) Infrequency of opportunities. Opportunities, in the form 

 of significant clues, do not come very often. This is the only 

 aspect aflfected by sheer chance, and even here the scientist does 

 not play a purely passive role. The successful researchers are 

 scientists who spend long hours working at the bench, and who 

 do not confine their activities to the conventional but try out 

 novel procedures, therefore they are exposed to the maximum 

 extent to the risk of encountering a fortunate " accident ". 



(b) Noticing the clue. Acute powers of observation are often 

 required to notice the clue, and especially the ability to remain 

 alert and sensitive for the unexpected while watching for the 

 expected. Noticing is discussed at length in the chapter on 

 observation, and it need only be said here that it is mainly a 

 mental process. 



(c) Interpreting the clue. To interpret the clue and grasp its 

 possible significance is the most difficult phase of all and requires 

 the " prepared mind ". Let us consider some instances of 

 failure to grasp opportunities. The history of discovery teems 



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