SECT. 9.] Fallacies. 339 



be accidental if it is the maximum of the respective returns 

 for several Departments 1 . The answer may be given one 

 way or the other according as we bear this consideration in 

 mind. 



9. We are peculiarly liable to be misled in this way 

 when we are endeavouring to determine the cause of some 

 phenomenon, by mere statistics, in entire ignorance as to the 

 direction in which the cause should be expected. In such 

 cases an ingenious person who chooses to look about over a 

 large field can never fail to hit upon an explanation which is 

 plausible in the sense that it fits in with the hitherto ob 

 served facts. With a tithe of the trouble which Mr Piazzi 

 Smyth expended upon the measurement of the great pyramid, 

 I think I would undertake to find plausible intimations of 

 several of the important constants and standards which he 

 discovered there, in the dimensions of the desk at which I am 

 writing. The oddest instance of this sort of conclusion is 

 perhaps to be found in the researches of a writer who has 

 discovered 2 that there is a connection of a striking kind 

 between the respective successes of the Oxford and the 

 Cambridge boat in the annual race, and the greater and less 

 frequency of sun-spots. 



Of course our usual practical resource in such cases is to 

 make appeal to our previous knowledge of the subject in 

 question, which enables us to reject as absurd a great number 

 of hypotheses which can nevertheless make a fair show when 

 they are allowed to rest upon a limited amount of adroitly 

 selected instances. But it must be remembered that if any 

 theory chooses to appeal to statistics, to statistics it must be 

 suffered to go for judgment. Even the boat race theory 



1 Discussed by Mr F.Y.Edgeworth, 2 Journal of the Statistical Soc. 



in the Phil. Mag. for April, 1887. (Vol. XLII. p. 328) Dare one suspect 



a joke? 



222 



