APPENDIX. 581 



would-be philosophers use to buoy up their ridiculous doc- 

 trines." 



There is a further curious mental trait exhibited by Mr. 

 Kirkman and which Professor Tait appears to have in com- 

 mon with him. Very truly it has been remarked that there is a 

 great difference between disclosing the absurdities contained 

 in a thing and piling absurdities upon it; and a remark to be 

 added is that some minds appear incapable of distinguishing 

 between intrinsic absurdity and extrinsic absurdity. The case 

 before us illustrates this remark; and at the same time shows 

 us how analytical faculties of one kind may be constantly 

 exercised without strengthening analytical faculties of another 

 kind how mathematical analysis may be daily practised with- 

 out any skill in psychological analysis being acquired. For 

 if these gentlemen had analyzed their own thoughts to any 

 purpose, they would have known that incongruous juxtaposi- 

 tions may, by association of ideas, suggest characters that do 

 not at all belong to the things juxtaposed. Did Mr. Kirkman 

 ever observe the result of putting a bonnet on a nude statue? 

 If he ever did, and if he then reasoned after the manner ex- 

 emplified above, he doubtless concluded that the obscene effect 

 belonged intrinsically to the statue, and only required the 

 addition of the bonnet to make it conspicuous. The alterna- 

 tive conclusion, however, which perhaps most will draw, is 

 that not in the statue itself was there anything of an obscene 

 suggestion, but that this effect was purely adventitious: the 

 bonnet, connected in daily experience with living women, 

 calling up the thought of a living woman with the head dressed 

 but otherwise naked. Similarly though, by clothing an idea 

 in words which excite a feeling of the ludicrous by their odd- 

 ity, any one may associate this feeling of the ludicrous with 

 the idea itself, yet he does not thereby make the idea ludi- 

 crous; and if he thinks he does, he shows that he has not prac- 

 tised introspection to much purpose. 



By way of a lesson in mental discipline, it may be not un- 

 instructive hefe to note a curious kinship of opinion between 

 these two mathematicians and two litterateurs. At first sight 

 it appears strange that men whose lives are passed in studies 

 so absolutely scientific as those which Professor Tait and Mr. 

 Kirkman pursue, should, in their judgments on the formula 

 of Evolution, be at one with two men of exclusively literary 

 culture a North American Reviewer and Mr. Matthew Ar- 

 nold. In the North American Review, vol. 120, page 202, a 



