Man is not yet an ideal creature. At his present best many of his ways are so unpleasant that they are unmentionable in polite society, and so painful that he is compelled to pretend that pain is often a good. Nature, also called Providence, holds no brief for the human experiment: it must stand or fall by its results. If Man will not serve, Nature will try another experiment.
George Bernard Shaw, Back to Methuselah, London, 1945, preface