[CHAPTER XIII]
THE OPPONENT OF MATERIALISM
Science and Metaphysics—Berkeley, Hume, and Hobbes—Existence of Matter and Mind—Descartes's Contribution—Materialism and Idealism—Criticism of Materialism—Berkeley's Idealism—Criticism of Idealism—Empirical Idealism—Materialism as opposed to Supernaturalism—Mind and Brain—Origin of Life—Teleology, Chance, and the Argument from Design.
The prosecution of independent thinking in any branch of knowledge leads to the ultimate problems of philosophy. The mathematician cannot ponder over the meaning of his figures, the chemist that of his reactions, the biologist that of his tissues and cells, the psychologist that of sensations and conceptions, without being tempted from the comparatively secure ground of observations and the arrangement of observations into the perilous regions of metaphysics. Most scientific men return quickly, repelled and perhaps a little scared by the baffling confusion of that windy region of thought where no rules of logic seem incontrovertible, no conclusions tenable, and no discussions profitable. Huxley, however, not only entered into metaphysical questions with enthusiasm, but gave a great deal of time to the study of some of the great metaphysical writers. His views are to be found scattered through very many of his ordinary scientific writings, but are specially set forth in a volume on Hume, which he wrote for Mr. John Morley's series, English Men of Letters, and in essays on Berkeley and on Descartes, all of which are republished in the Collected Essays. He contrived to preserve, in the most abstrusely philosophical of these writings, a simplicity and clarity which, although they have not commended him to professional metaphysicians, make his attitude to the problems of metaphysics extremely intelligible. The greatest barrier and cause of confusion to the novice in metaphysics is that the writings of most of the great authorities are overburdened by their great knowledge of the history of philosophy. Huxley, in a characteristic piece of "parting advice" in the preface to his work on Hume attacked this confusion between the history of a subject and the subject itself.
"If it is your desire," he wrote, "to discourse fluently and learnedly about philosophical questions, begin with the Ionians and work steadily through to the latest new speculative treatise. If you have a good memory and a fair knowledge of Greek, Latin, French, and German, three or four years spent in this way should enable you to attain your object. If, on the contrary, you are animated by the much rarer desire for real knowledge; if you want to get a clear conception of the deepest problems set before the intellect of man, there is no need, so far as I can see, for you to go beyond the limits of the English tongue. Indeed, if you are pressed for time, three English authors will suffice, namely, Berkeley, Hume, and Hobbes."
The first and perhaps the greatest problem in metaphysics can be put very shortly. What is the reality behind the apparent universe of matter and mind we see around us? Or, rather, what do we know of that reality? To the uninitiated in philosophical thinking it seems sufficiently plain that there are two entities, body and soul in man, matter and mind in the whole universe; and various types of intelligent dogmatists, ranging from the sturdy if somewhat stupid shrewdness of Dr. Johnson to the agile casuistry of Catholic metaphysicians, have supported this simple verdict of "common sense." Trouble begins, however, with any attempt to analyse the relations between what we call "matter" and what we call "mind." It appears, for instance, that what we call matter we only know in terms of mind. In an essay on Descartes's Discourse on Method, Huxley explains this by simple examples.
"I take up a marble and I find it to be a red, round, hard, single body. We call the redness, the roundness, the hardness and the singleness, 'qualities' of the marble; and it sounds, at first, the height of absurdity to say that all these qualities are modes of our own consciousness, which cannot even be conceived to exist in the marble. But consider the redness, to begin with. How does the sensation of redness arise? The waves of a certain very attenuated matter, the particles of which are vibrating with vast rapidity, but with very different velocities, strike upon the marble, and those which vibrate with one particular velocity are thrown off from its surface in all directions. The optical apparatus of the eye gathers some of these together, and gives them such a course that they impinge upon the surface of the retina, which is a singularly delicate apparatus connected with the terminations of the fibres of the optic nerve. The impulses of the attenuated matter, or ether, affect this apparatus and the fibres of the optic nerve in a certain way; and the change in the fibres of the optic nerve produces yet other changes in the brain; and these, in some fashion unknown to us, give rise to the feeling, or consciousness, of redness. If the marble could remain unchanged, and either the vibrations of the ether, or the nature of the retina, could be altered, the marble would seem not red, but some other colour. There are many people who are what are called colour-blind, being unable to distinguish one colour from another. Such an one might declare our marble to be green; and he would be quite as right in saying that it is green as we are in declaring it to be red. But then, as the marble itself cannot be both green and red, at the same time, this shews that the quality redness must be in our consciousness and not in the marble."
In similar fashion he shewed that the hardness, roundness, and even the singleness of the marble were, so far as we know, states of our consciousness and not in the marble. The argument is capable of application to all that we call matter, and it thus appears, on analysis, that what we know of matter is simply a series of states of our consciousness, or mind. In similar fashion, it turns out that what we call mind is, so far as practical experience goes, always associated with and dependent on what we call matter. We have no direct knowledge of thinking without a brain, or of consciousness without a body. Alterations and changes in matter, as for instance in the tissues and nutrition of the body, are, so far as our experience goes, inseparably associated with mental operations. In the animal kingdom we see the development of the mind creeping slowly after the development of the material nervous system, until, in man, the most complex mind and most complex consciousness of which we have knowledge accompany the most complex body and brain.