I can't myself agree in some of your theories. _A priori_, your muscular sense-theory of psychic measurements seems to me incredible in many ways. Your general mechanical _Welt-anschauung_ is too abstract and simple for my mind. But I find in you just what is lacking in this critique of Müller's--a sense for the perspective and proportion of things (so that, for instance, you _don't_ make experiments and quote figures to the 100th decimal, where a coarse qualitative result is all that the question needs). Whose _theories_ in Psychology have any _definitive_ value today? No one's! Their only use is to sharpen farther reflexion and observation. The man who throws out most new ideas and immediately seeks to subject them to experimental control is the most useful psychologist, in the present state of the science. No one has done this as yet as well as you. If you are only _flexible_ towards your theories, and as ingenious in testing them hereafter as you have been hitherto, I will back you to beat the whole army of your critics before you are forty years old. Too much ambition and too much rashness are marks of a certain type of genius in its youth. The _destiny_ of that genius depends on its power or inability to assimilate and get good out of such criticisms as Müller's. Get the good! forget the bad!--and Müller will live to feel ashamed of his tone. I was very much grieved to learn from Delabarre lately that the doctors had found some weakness in your heart! What a wasteful thing is Nature, to produce a fellow like you, and then play such a trick with him! Bah!--But I prefer to think that it will be no serious impediment, if you only go _piani piano_. You will do the better work doubtless for doing it a little more slowly. Not long ago I was dining with some old gentlemen, and one of them asked, "What is the best assurance a man can have of a long and active life?" He was a doctor; and presently replied to his own question: "To be entirely broken-down in health before one is thirty-five!"--There is much truth in it; and though it applies more to nervous than to other diseases, we all can take our comfort in it. _I_ was entirely broken-down before I was thirty. Yours cordially, WM. JAMES. Delabarre and Mackaye wrote to me of you with great admiration and gratitude for all they have gained. _To Henry Holt._ CHOCORUA, N.H., _July 24, 1891_. MY DEAR HOLT,--I expect to send you within ten days the MS. of my "Briefer Course," boiled down to possibly 400 pages. By adding some twaddle about the senses, by leaving out all polemics and history, all bibliography and experimental details, all metaphysical subtleties and digressions, all quotations, all humor and pathos, all _interest_ in short, and by blackening the tops of all the paragraphs, I think I have produced a tome of pedagogic classic which will enrich both you and me, if not the student's mind.