THE LOGIC OF SCIENCE 40S 



shall we hold that biology is entitled by the nature of its 

 problems to operate with the conception of a real efficacy of 

 mind, in spite of the fact that the (methodological) principle 

 of the conservation of energy is usually so stated as to rule out 

 the possibility that what is classified as " psychical" can initiate 

 "physical" changes? If we grant to a science this licence to 

 go on its own way without regard to the way it contradicts 

 principles which are useful in another science, we must 

 evidently appeal to the doctrine that conflicting hypotheses 

 may be provisionally used. This will seem more reasonable 

 when we recollect that originally all hypotheses were devised 

 by us for our use. Or again, how much emphasis is it legiti- 

 mate to put on the corollary that if vital phenomena are more 

 than "mechanical," they are mechanically incalculable and 

 "free"? Clearly if this is over-emphasised, it will conflict with 

 the tacit scientific postulate that whatever it is desired to 

 investigate must be assumed to be knowable. Hence it may 

 be well to remind ourselves that what is not mechanically 

 calculable need not be, on that account, incalculable altogether, 

 and that actions and events may be foreseen also by an appeal 

 to psychological principles. In both cases the more tolerant 

 attitude towards these corollaries of vitalism will probably be to 

 the greater advantage of science, and, if we adopt it, I can see 

 nothing in Sir Oliver Lodge's pronouncements that would 

 justify the rejection of his vitalism as anti-scientific. 



But its vitalism is not the greatest stumbling-block of Sir 

 Oliver Lodge's Address. His plea for "Psychical Research" is 

 undoubtedly still more of a shock to the susceptibilities of many. 

 Here again, however, I hold that the logic of science substantially 

 justifies his attitude, even though those who see this may not 

 all agree that the evidence accumulated up to date by Psychical 

 Research is such as to generate in themselves a positive and 

 assured belief that immortality has been proved. 



An impartial logician, i.e. one who is aware of his personal 

 bias and endeavours to counteract it, would I think at present 

 feel unable to attribute such high value to the evidence in 

 question. Not because he personally disbelieves it or fails to 

 recognise that it is a considerable improvement on the evidence 

 that was in existence when the Society for Psychical Research 

 began its operations and for the first time in the world's history 

 attempted to investigate the most momentous of all questions in 



