Charles Galton Darwin, in his book, The Next Million Years:
From the Epilogue
Anyone who disagrees with my forecast must try to get beyond a vague optimism, which merely expresses the confidence that “something will turn up.” In particular he must find a really solid reason which shows how the threat of over-population will be avoided; the observation that it has been avoided in some countries during the last few years is not enough. Let him then give the fullest rein to his imagination, let him suppose that anything is permissible, but let him follow out the consequences to their conclusion. I will venture to say that if he does so he will find that one or other of two alternatives is the result. Either he will come to general conclusions not so very different from mine; he will find that his utopia, however pleasant it may be in other ways, in the long run will suffer from many disagreeable features of the kind that I have been considering. Or else he will find that his imagination has gone so far out of the realms of reality that it contradicts the physical or the biological laws of nature.
Nevertheless for all of us it is intolerable to think of the future unfolding itself in complete predestined inevitability for the eternity of a million years. There are two things we must do; one is to know, the other to act. As to knowing, in my introductory chapter I described an analogy in mechanics, and I suggested that it should be possible to discover a set of laws, like the laws of thermodynamics, which would place absolute limits on what can be done by humanity. Biological laws cannot be expected to have the same hard outline as physical laws, but still there are absolute laws limiting what an animal can do, and similar laws will limit man not only on his physical side, but also on his intellectual side. If these could be clearly stated, we should recognize that many attempts that have been made at improving man’s estate were hopeless.
If it is for others, better versed than I am in the biological sciences, to work out these laws, and it is in all humility that I put forward the basis, on which, it may be, that they could be founded. The first principle is that man, as an animal, obeys the law of variation of species, which condemns human nature to stay nearly constant for a million years. The perfectibility of mankind, the aim of so many noble spirits, is foredoomed by this principle. The second is that man is a wild animal, and that doctrines drawn from the observation of domestic animals are quite inapplicable to him. The third principle is the non-inheritance of acquired characters, a principle familiar in animal biology, but all too seldom invoked in connection with human beings. If these, and any further principles as well, or any alternatives to them, were accepted, it might sometimes be possible to show up the absurdities of bad statesman to work within their limitations, because only so could he hope to achieve success.