574 The Outline of Science 



At least the bare possibility of messenger-communication will 

 help to prevent too easy and certain a conviction about the ex- 

 istence of wholly unproven "brain-waves." The testing of work- 

 ing hypotheses is a commonplace procedure in science. Such 

 hypotheses do no harm if they are lightly held, and if a key is 

 not unduly pressed into keyholes which it does not fit. Some 

 good judges think that a mysterious non-vocal method of inter- 

 communication may have been inherited from an animal and 

 savage ancestry, though it has now become almost overlaid and 

 suppressed by civilisation and disuse. 



3 



Concerning Citation of Illustrative Examples 



If instances or samples of each or of some of the things 

 which are said to occur are quoted in this article, it can only be 

 by way of illustration, not as evidence of fact. For to give any- 

 thing like real evidence, all manner of details of time and place 

 must be supplied, together with confirmatory testimony and 

 extracts from any relevant documents that may be available. 

 The securing of evidence is a troublesome business, involving 

 the interviewing of witnesses, the examining of places, the obtain- 

 ing of signed statements, and generally the securing of details 

 which, however instructive and necessary, are laborious to collect 

 and bulky to record. Recorded testimony of this kind must 

 be sought in the Proceedings and Journal of a scientific society 

 and other serious publications. If it be complained they are not 

 easy reading, that is a disadvantage they share with the Proceed- 

 ings of learned societies in general. They do not aim at being 

 easy, they aim at being exact and trustworthy. So the samples 

 here and there cited below, though based upon actual statements, 

 may be taken as mere assertions, or at best as illustrations or 

 types of what has to be substantiated, or else criticised and 

 demolished, elsewhere. 



