A hundred years ago Malthus, a prophet if not a seer, recognised our danger and within the past quarter of a century a dozen theorists have proposed remedies less stringent than those advocated by Malthus, but almost equally futile. Among the theorists are those perhaps unconscious reactionaries who advocate the simple life, by a return to natural food and conditions, in endlessly varying ways. To them in their search for natural foods and conditions we would point out that countless generations separate us from primitive man, a lapse of time during which our functions have become gradually adapted to new habits and environment, and that if it were possible by universal agreement for the peoples of Europe to return instantly to primitive methods of living, the effect would be no less disastrous than the reversal of the process, the sudden thrusting of our civilisation upon savage tribes whereby, to quote one or two recent examples only, the aborigines of North America, New Zealand, and Japan (the Ainu tribes) have become, or are rapidly becoming, extinct. When therefore we point out man’s power of adaptability in this connexion, the emphasis is thrown on the slowness with which that adaptability is passed on to our descendants and on the relative permanence of the new powers acquired. For our purpose the argument remains good whether we admit or deny the inheritability of acquired characteristics, our point being that in either case the process is necessarily a slow one, though it is plainly more rapid if the hypothesis be true.[3] From the savage to the civilised state, man passed, as I say, so slowly that the passing in the early stages caused neither difficulties nor changes sufficiently marked to force themselves on our recognition. In other words, the subject of these changes was unconscious of them, and the habit of depending upon these sensory appreciations (“feeling-tones,” or “sense of feeling”) dominant by right in the savage or subconsciously directed state, remained firmly established in the civilised experiences, so that to-day man walks, talks, sits, stands, performs in fact the innumerable mechanical acts of daily life without giving a thought to the psychical and physical processes involved.