MY DEAR SIR,--I read the copy of your "Matière et Mémoire" which you so kindly sent me, immediately on receiving it, four years ago or more. I saw its great originality, but found your ideas so new and vast that I could not be sure that I fully understood them, although the _style_, Heaven knows, was lucid enough. So I laid the book aside for a second reading, which I have just accomplished, slowly and carefully, along with that of the "Données Immédiates," etc. I think I understand the main lines of your system very well at present--though of course I can't yet trace its proper relations to the aspects of experience of which you do not treat. It needs much building out in the direction of Ethics, Cosmology and Cosmogony, Psychogenesis, etc., before one can apprehend it fully. That I should take it in so much more easily than I did four years ago shows that even at the age of sixty one's mind can grow--a pleasant thought. It is a work of exquisite genius. It makes a sort of Copernican revolution as much as Berkeley's "Principles" or Kant's "Critique" did, and will probably, as it gets better and better known, open a new era of philosophical discussion. It fills _my_ mind with all sorts of new questions and hypotheses and brings the old into a most agreeable liquefaction. I thank you from the bottom of my heart. The _Hauptpunkt_ acquired for me is your conclusive demolition of the dualism of object and subject in perception. I believe that the "transcendency" of the object will not recover from your treatment, and as I myself have been working for many years past on the same line, only with other general conceptions than yours, I find myself most agreeably corroborated. My health is so poor now that work goes on very slowly; but I am going, if I live, to write a general system of metaphysics which, in many of its fundamental ideas, agrees closely with what you have set forth and the agreement inspires and encourages me more than you can well imagine. It would take far too many words to attempt any detail, but some day I hope to send you the book.[42] How good it is sometimes simply to _break away_ from all old categories, deny old worn-out beliefs, and restate things _ab initio_, making the lines of division fall into entirely new places! I send you a little popular lecture of mine on immortality,[43]--no positive theory but merely an _argumentum ad hominem_ for the ordinary cerebralistic objection,--in which it may amuse you to see a formulation like your own that the brain is an organ of _filtration_ for spiritual life. I also send you my last book, the "Varieties of Religious Experience," which may some time beguile an hour. Believe, dear Professor Bergson, the high admiration and regard with which I remain, always sincerely yours, Wm. James. _To Mrs. Louis Agassiz._ Cambridge, _Dec. 15, 1902_.