CONCLUSION 347 



I think that the "success" theory of reasoning will 

 not be much appreciated by the pure mathematician. 

 For him reasoning is a heaven-sent faculty to be enjoyed 

 remote from the fuss of external Nature. It is heresy 

 to suggest that the status of his demonstrations depends 

 on the fact that a physicist now and then succeeds in 

 predicting results which accord with observation. Let 

 the external world behave as irrationally as it will, there 

 will remain undisturbed a corner of knowledge where 

 he may happily hunt for the roots of the Riemann- 

 Zeta function. The "success" theory naturally justifies 

 itself to the physicist. He employs this type of activity 

 of the brain because it leads him to what he wants — a 

 verifiable prediction as to the external world — and for 

 that reason he esteems it. Why should not the theo- 

 logian employ and esteem one of the mental processes 

 of unreason which leads to what he wants — an assurance 

 of future bliss, or a Hell to frighten us into better 

 behaviour? Understand that I do not encourage theo- 

 logians to despise reason; my point is that they might 

 well do so if it had no better justification than the 

 "success" theory. 



And so my own concern lest I should have been 

 talking nonsense ends in persuading me that I have to 

 reckon with something that could not possibly be 

 found in the physical world. 



Another charge launched against these lectures may 

 be that of admitting some degree of supernaturalism, 

 which in the eyes of many is the same thing as super- 

 stition. In so far as supernaturalism is associated with 

 the denial of strict causality (p. 309) I can only answer 

 that that is what the modern scientific development of 

 the quantum theory brings us to. But probably the 

 more provocative part of our scheme is the role allowed 



