blance between animal and human psychology. So far, therefore, as we are now concerned with the will, we have only to note that up to the point where the volitions of a man begin to surpass those of a brute in respect of complexity, refinement, and foresight, no one disputes identity of kind.
Lastly, the same remark applies to the faculties of intellect. Enormous as the difference undoubtedly is between these faculties in the two cases, the difference is conceded not to be one of kind ab initio. On the contrary, it is conceded that up to a certain point—namely, as far as the highest degree of intelligence to which an animal attains—there is not merely a similarity of kind but an identity of correspondence. In other words, the parallel between animal and human intelligence which is presented in the diagram is not disputed. The question, therefore, only arises with reference to those superadded faculties which are represented above the level marked twenty-eight, where the upward growth of animal intelligence ends, and the growth of distinctively human intelligence begins. But even at level twenty-eight the human mind is already in possession of many of its most useful faculties, and these it does not afterward shed, but carries them upward with it in the course of its further development—as we well know by observing the psychogenesis of every child. Now, it belongs to the very essence of evolution, considered as a process, that when one order of existence passes on to higher grades of excellence, it does so upon the foundation already laid by the previous course of its progress; so that when compared with any allied order of existence which has not been carried so far in this upward course, a more or less close parallel admits of being traced between the two, up to the point at which the one begins to distance the other, where all further comparison admittedly ends. Therefore, upon the face of them, the facts of comparative psychology now before us are, to say the least, strongly suggestive of the superadded powers of the human intellect having been due to a process of evolution.
Lest it should be thought that in this preliminary sketch of the resemblances between human and brute psychology I have been endeavoring to draw the lines with a biased hand, I will here quote a short passage to show that I have not misrepresented the extent to which agreement prevails among adherents of otherwise
- Of course, my opponents will not allow that this word can be properly applied to the psychology of any brute. But I am not now using it in a question-begging sense: I am using it only to avoid the otherwise necessary expedient of coining a new term. Whatever view we may take as to the relations between human and animal psychology, we must in some way distinguish between the different ingredients of each, and so between the instinct, the emotion, and the intelligence of an animal. (See "Mental Evolution in Animals," p. 335 et seq.)