REASON 



formulated as the ultimate truth, but probably most following 

 him did until Einstein showed how well-founded Newton's 

 caution had been. In less fundamental matters how often do we 

 see widely accepted notions superseded ! 



Therefore the scientist cannot afford to allow his mind to 

 become fixed, with reference not only to his own opinions but 

 also to prevailing ideas. Theobald Smith said : 



" Research is fundamentally a state of mind involving con- 

 tinual re-examination of doctrines and axioms upon which 

 current thought and action are based. It is, therefore, critical of 

 existing practices."*^ 



No accepted idea or " established principle " should be regarded 

 as beyond being questioned if there is an observation challenging 

 it. Bernard wrote : 



" If an idea presents itself to us, we must not reject it simply 

 because it does not agree with the logical deductions of a reign- 

 ing theory." 



Great discoveries have been made by means of experiments 

 devised with complete disregard for well accepted beliefs. 

 Evidently it was Darwin who introduced the expression " fool's 

 experiment " to refer to such experiments, which he often under- 

 took to test what most people would consider not worth testing. 



People in most other walks of Ufe can allow themselves the 

 indulgence of fixed ideas and prejudices which make thinking 

 so much easier, and for all of us it is a practical necessity to hold 

 definite opinions on many issues in everyday life, but the research 

 worker must try to keep his mind malleable and avoid holding 

 set ideas in science. We have to strive to keep our mind receptive 

 and to examine suggestions made by others fairly and on their 

 own merits, seeking arguments for as well as against them. We 

 must be critical, certainly, but beware lest ideas be rejected 

 because an automatic reaction causes us to see only the arguments 

 against them. We tend especially to resist ideas competing with 

 our ov^m. 



A useful habit for scientists to develop is that of not trusting 

 ideas based on reason only. As Trotter says, they come into the 

 mind often with a disarming air of obviousness and certainty. 

 Some consider that there is no such thing as pure reasoning, that 

 is to say, except where mathematical symbols are involved. 



89 



