“In instinct all is innate. The beaver builds without having learned to build: all that he does is from fatality. The beaver builds under the impulsion of a constant and irresistible force.
“In understanding, every thing results from experience and instruction. The dog obeys only because he has learned to obey: he is perfectly free in this respect; for he obeys only because he will obey.
“Finally, in regard to instinct every thing is particular. That admirable industry that the beaver exhibits in the construction of his hut, can be employed in no other occupation than the building of his hut. Now, in understanding every thing is general; for the dog could apply the same flexibility of attention, and of conception, which he uses in obeying, to do any other thing.
“In animals there are, therefore, two distinct and primary forces—instinct and understanding. As long as our conceptions of these forces were confused, all our views and opinions in regard to the actions of animals remained obscure and contradictory. Among these actions, some exhibited man every where superior to the brute; while others appeared to accord to the brute creation the superiority over man—a contradiction almost as deplorable as absurd! By the distinction that separates blind and necessary actions from elective and conditional ones—or, in a word, instinct from intelligence—all contradiction disappears, and order succeeds to confusion. Whatever in animals is understanding, does not in any degree approach the excellence of the human understanding; and whatsoever, under the appearance of understanding, seemed superior to the human understanding, is in fact a mere result of a mechanical and blind force.”[187]
Here is what I say as to the boundaries between the intelligence of man and of animals.
“Animals receive, through their senses, impressions similar to those that we receive through the medium of our senses; like ourselves, they retain the traces of these impressions: these impressions, when preserved, form for them, as well as for us, numerous and various associations: they combine them, they draw from them inferences, and deduce judgments from them: therefore they possess understanding.
“But the whole of their understanding stops at that point. The understanding they possess is not one that can consider itself: it cannot see itself, does not know itself. They do not possess reflection, that supreme faculty with which the mind of man is endowed, and which enables him to turn his intellectual power inwards, so as to study and know the nature of his own understanding.
“Reflection, thus defined, is then the boundary that separates human intelligence from that of the brute creation: and in fact it cannot be denied that this furnishes a strong line of demarcation between them. Thought, which contemplates itself; understanding, which sees itself and studies itself; knowledge, which knows itself; these evidently constitute an order of determinate phenomena of a decided character, and to which no brute animal can ever attain. This is, if one might so speak, a purely intellectual domain; and it appertains to man alone. In one word, animals feel, know, think; but man is the only one of all created beings to whom has been given the power of feeling that he feels, of knowing that he knows, and of thinking that he thinks.”[188]
I will quote, also, the following passage from my work sur l’instinct et l’intelligence des animaux, p. 178, et seq.
“ ... There are three facts: instinct, understanding of brutes, and human understanding; and each of these facts has its definite limits.