336 MENTAL EVOLUTION IN ANIMALS. 



ing account of the exliibition of Eeason on the part of a 

 Crab : — " Mr. Gardner, whilst watching a shore crab {gelasi- 

 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."t I shall, therefore, pro- 

 ceed to consider the very prevalent opinion to which such a 

 commentary introduces us, and wliich 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, lolurever there is a 

 process of inference from them, which results in establishing 

 a proportional conclusion among them, there we have some- 

 thins^ 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. 



