[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.
All those conditions which we accept as requisite to the perfection of man in the moral and material world may be included in one fundamental sentence: The perfection of man consists in his ability to exercise his powers in the observation of the plan of the world; and since between the measure of the power and the end towards which it works there must exist the completest harmony, perfection will consist in the highest possible activity of his powers, and, at the same time, in their mutual subordination. But the action of the human soul is—from a necessity which I do not understand—bound fast to the action of matter. The changes in the world of matter must be modified and, so to speak, refined by a peculiar class of secondary powers—I mean the senses—before they can produce in me any corresponding ideas; while, on the other hand, a fresh set of organic powers, the agents of voluntary movements must come into play between the inner spirit and the outward world in order to make the changes of the former tell upon the latter; thus must the operations of thinking and sensation alike correspond to certain movements of the internal sensorium. All this goes to make up the organism of the soul's activities.
But matter is spoil stolen from the eternal change, and wears itself away, even as it works; in its movement its very element is driven from its grooves, chased away and lost. Because now, on the contrary, that simple essence, the soul, possesses in itself permanence and stability, and in its essence neither gains nor loses aught,—matter cannot keep step with the activity of the spirit, and there would thus soon be an end of the organism of spiritual life, and therewith of all action of the soul. To prevent which there must be added to the first system or organic powers a second one, which shall make good the losses sustained, and sustain the decay by a chain of new creations ready to take the place of those that have gone. This is the organism of maintenance.
Still further. After a short period of activity, when the equal balance of loss and reparation is once removed, man quits the stage of life, and the law of mortality depopulates the earth. There is not room enough for the multitude of sentient beings, whom eternal love and wisdom seemed to have called to a happy existence, to live side by side within the narrow boundaries of our world, and the life of one generation shuts out the life of another. Therefore was it necessary that new men should appear, to take the place of those who had departed, and that life should be kept up in unbroken succession. But of creation there is no longer any trace; what now becomes new becomes so only by development. The development of man must come to pass through man, if it is to bear a proportion to the original number, if man is to be cultivated into man. On this account a new system of organic powers was added to the two that had preceded it, which had for its object to quicken and to develop the seed of humanity. This is the organism of generation.
These three organisms, brought into the most thorough connection, local and real, go to form the human body.
S 3.—The Body.