378 JAMES CLERK MAXWELL. [CHAP. XII. 



confess, was with me, as I found it was with Litchfield, 

 partly that of recognising an old well-remembered style, and 

 reflecting that here at least was something which might be 

 " thought to be beyond the reach of change." ... By the 

 way, Boole is "one of the profoundest mathematicians of 

 our time;" but how about "thinkers"? Certainly his ex- 

 positions of the principle of a piece of mathematics are 

 beautiful up to and, I don't doubt, beyond my appreciating. 

 But that last chapter of the Laws, etc., from which you 

 quote, with Empedocles and Pseudo-Origen and the rest of 

 them, always seems to me to render a sound as of a largish 

 internal cavity ; and the whole book, taken together with 

 his E.S.E. paper on testimony and least squares, presents, I 

 think, too many instances of a particular class of fallacy I 

 know I am speaking blasphemies, but there would be a 

 strike among the postmen if I put in all the necessary 

 qualifications too many instances to be got over, not in 

 absolute number if they were of different kinds, for anybody 

 may make mistakes, but too many of one kind. The kind 

 is insufficient interpretation) i.e. letting your equations lead 

 you by the nose. The most serious example, I maintain 

 it is an example, is his insisting that his theory of logic is 

 not founded on quantity, so that it furnishes (he holds) an 

 independent foundation for probabilities, independent of the 

 usual quantitative foundation. That this is a fallacy, and 

 that in particular it is an example of the fallacy of insuffi- 

 cient interpretation, is evident surely when you find that, 

 even in the higher case of " secondary " propositions, the 

 elective symbols represent in his own opinion quantities of 

 " time " after all. With regard to the sentence you quote, 

 I am always suspicious of any inclination I may feel to find 

 a question too easy ; and, independently of that, your quot- 

 ing it is itself a staggerer. But the difficulty I confess 

 does strike me as a rather artificial one. There is nothing, 

 scarcely, in which I think Mill is so right and the Hamilton- 

 ians so wrong as that question about logic being the laws of 

 thought. Hamilton says as tliought, Mill says as valid, and 

 so does Boole and so do you ; but if Mill is right, where is 



