336 MENTAL EVOLUTION IN ANIMALS. 



ing account of the exhibition of Reason on the part of a 

 Crab : — " Mr. Gardner, whilst watching a shore crab (gzlasi- 

 mus) making its burrow, threw some shells towards the hole. 

 One rolled in, and three other shells remained within a few 

 inches of the mouth. In about five minutes the crab brought 

 out the shell which had fallen in, and carried it away to the 

 distance of a foot ; it then saw the three other shells lying 

 near, and evidently thinking that they might likewise roll in, 

 carried them to the spot where it had laid the first. It 

 would, I think, be difficult to distinguish this act from one 

 performed by man by the aid of reason."* 



Mr. Mivart, after quoting the above, calls the concluding- 

 sentence an " astonishing remark."f I shall, therefore, pro- 

 ceed to consider the very prevalent opinion to which such a 

 commentary introduces us, and which consists, as I have said, 

 in regarding the faculty of Eeason as the special prerogative 

 of Man. 



I must begin by again observing that the faculty of 

 Eeason, in the sense of a " knowledge of the relation between 

 means employed and ends attained, .... admits of 

 numberless degrees ; " and I hold it to be a mistake, greater 

 than any other that has been committed in psychological 

 science, to_ suppose that there is any difference of kind 

 whether this faculty is exercised with reference to the highest 

 abstractions of introspective thought, or to the lowest pro- 

 ducts of sensuous perception ; whether the ideas involved are 

 general or special, complex or simple, wherever there is a 

 process of inference from them which results in establishing 

 a proportional conclusion among them, there we have some- 

 thing more than the mere association of ideas; and this 

 something is Eeason. If I were to see a large stone falling 

 through the roof of my conservatory, and on climbing to the 

 wall above saw three or four other stones just upon the edge, 

 I should infer that the stones which fell previously stood in 

 a similar relation to my conservatory, and therefore that it 

 would be desirable to remove the others from their threaten- 

 ing position. This would not be an act of association, but an 

 act of reason (though a simple one), and it is psychologically 

 identical with the act which was performed by the crab. 



Further, according to J. S. Mill, " all inference is from 

 particulars to particulars: General propositions are merely 



* Descent of Man, p. 270. f Lessons from Nature, p. 213. 



