The work to which allusion has just been made was published in 1888, and, as far as I am aware, it is only now that Prof. Max Müller has sought to meet my views as there expressed. Hence we may take it that his answer is, at all events, well matured. Furthermore, we may take it, from the tone in which his answer is conveyed, that he credits me with having had at least an honest desire to understand, and accurately to represent, his meaning in all the places where I have ventured to criticise it. It appears, however, that at all events in one important respect I have betrayed “a complete misapprehension” of his meaning—viz. with reference to his “theory of the origin of roots” (_The Monist_, p. 582); and it is for the purpose of correcting this misapprehension that he has published the latter half of his present paper. My reply, therefore, must take the form of excusing myself for the complete misapprehensions which are alleged. It is desirable at the outset to emphasise a distinction which I was careful to draw in my work on “Mental Evolution in Man”—that, namely, between philology and philosophy. A man may be an excellent authority on the “Science of Language,” and yet but a very indifferent writer on the “Science of Thought.” On the other hand, a man may know nothing at first hand touching the special province of a philologist, and nevertheless be fully capable of criticising what a philologist has published in the way of theoretical deductions from his facts—especially where these deductions quit the sphere of philology, and soar into that of Darwinian, or anti-Darwinian, speculation. This distinction, indeed, between the particular science of philology and the general scope of philosophy, Prof. Max Müller himself recognises where he says: “While the student of language seems to me to have a perfect right to treat the roots of language as ultimate facts, it is difficult for the philosopher not to look beyond.” (_The Monist_, p. 579.) Nevertheless he complains of me because, while accepting all his philological facts upon his authority as a philologist (save in so far as they are not accepted by other philologists), I have been obliged to express dissent from not a few of his theoretical deductions—especially, as I have already indicated, where these have reference to the general doctrine of evolution as applied to the mind of man. But how, I may ask, could a treatise be written on “Mental Evolution in Man,” or “The Origin of Human Faculty,” without considering the results which have been gained by the science of comparative philology? Or how can it be maintained that, in order to deal with these results in relation to the general theory of descent, a writer must first of all himself become an authority in that particular science? At any rate, I deemed it enough for the only purposes which I had in view, to read attentively all the leading authorities in this science, and, after extracting from them the information upon matters of