It seems to me that many theories of the universe may be dismissed at once, not as too good, but as too cosy, to be true. One feels sure that they could have arisen only among people living a peculiarly sheltered life at a peculiarly favourable period of the world’s history. No theory need be seriously considered unless it recognises that the world has always been for most men and all animals other than domestic pets a scene of desperate struggle in which great evils are suffered and inflicted. No theory need be seriously considered unless it recognises how utterly alien most of the non-human life even on this small planet is to man and his ideals; how slight a proportion ostensibly living matter bears to the matter which is ostensibly inanimate; and that man himself can live and thrive only by killing and eating other living beings, animal or vegetable. Any optimism which is not merely silly and childish must maintain itself, if it can, in spite of and in conscious recognition of these facts.

C. D. Broad, Examination of McTaggart’s Philosophy, Cambridge, 1938, vol. 2, p. 774