And here it is, as I have acknowledged, that the great psychological distinction is to be found. Nevertheless, even here it must be conceded that up to a certain point, as between the brute and the man, there is not merely a similarity of kind, but an identity of correspondence. The distinction only arises with reference to those superadded faculties of ideation which occur above the level marked 28 in my diagram—_i.e._ where the upward growth of animal intelligence ends, and the development of distinctively human faculty begins. So that in the case of intellect, no less than in that of emotion, instinct, and volition, there can be no doubt that the human mind runs exactly parallel with the animal, up to the place where these superadded powers of intellect begin to supervene. Therefore, upon the face of them, the facts of comparative psychology thus far, to say the least, are strongly suggestive of these superadded powers having been due to a process of continued evolution. So much, then, for the points of agreement between animal and human psychology. Turning next to the points of difference, we had first to dispose of certain allegations which were either erroneous in fact or plainly unsound in theory. This involved a rejection _in toto_ of the following distinctions—namely, that brutes are non-sentient machines; that they present no rudiments of reason in the sense of perceiving analogies and drawing inferences therefrom; that they are destitute of any immortal principle; that they show no signs of progress from generation to generation; that they never employ barter, make fire, wear clothes, use tools, and so forth. Among these sundry alleged distinctions, those which are not demonstrably false in fact are demonstrably false in logic. Whether or not brutes are destitute of any immortal principle, and whether or not human beings present such a principle, the science of comparative psychology has no means of ascertaining; and, therefore, any arguments touching these questions are irrelevant to the subject-matter on which we are engaged. Again, the fact that brutes do not resemble ourselves in wearing clothes, making fire, &c., clearly depends on an absence in them of those powers of higher ideation which alone are adequate to yield such products in the way of intelligent action. All such differences in matters of detail, therefore, really belong to, or are absorbed by, the more general question as to the nature of the distinction between the two orders of _ideation_. To this, therefore, as to the real question before us, we next addressed ourselves. And here it was pointed out, _in limine_, that the three living naturalists of highest authority who still argue for a difference of kind between the brute and the man, although they agree in holding that only on grounds of psychology can any such difference be maintained, nevertheless upon these grounds all mutually contradict one another. For while Mr. Mivart argues that