[1] Huxley, speaking of psychology and physiology (idealism and materialism), says: "Our stem divides into two main branches, which grow in opposite ways, and bear flowers which look as different as they can well be. But each branch is sound and healthy, and has as much life and vigor as the other. If a botanist found this state of things in a new plant, I imagine he might be inclined to think that his tree was monoecious, that the flowers were of different sexes, and that, so far from setting up a barrier between the branches of the tree, the only hope of fertility lay in bringing them together. This is my notion of what is to be done with physics and metaphysics. Their differences are complementary, not antagonistic, and thought will never be completely fruitful until the one unites with the other."--HUXLEY, Macmillan's Mag., May 1870. Descartes' method (according to Huxley) leads straight up to the critical idealism of his great successor, Kant, in declaring that the ultimate fact of all knowledge is a consciousness and therefore affirming that the highest of all certainties, and indeed the only absolute certainty, is the existence of mind. But it stops short of Berkeley in declaring that matter does not exist: his arguments against its existence would equally tend to prove the non-existence of soul. In Descartes' stem, the body is simply a machine, in the midst of which the rational soul (peculiar to man) is lodged, and which it directs at its will, as a skilful engineer familiar with its working might do--through will and through affection he can "increase, slacken, and alter their movements at his pleasure." At the same time, he admits, in all that regards its mere animal life--in active functions, such as those connected with hunger, respiration, sleep, digestion; in many passive ones, such as we are accustomed to call mental, as in memory, the perception of color, sound--a purely automatic action of the body, which it pursues simply by following out its own laws, independent of the soul's direction or interference. PHYSICAL CONNECTION. THE ANIMAL NATURE STRENGTHENS THE ACTION OF THE SPIRIT. S 2.--Organism of the Operations of the Soul--of its Maintenance and Support--of Generation.