The long history of war as a racial habit explains why a ruinous and insane anachronism shows such tenacity; for the conditions which established the habit among primitive tribes demonstrably no longer exist. It is probably true, as William James says, that 'militarist writers without exception regard war as a biological or sociological necessity'; lawyers might say the same about litigation. But laws of nature 'are not efficient causes, and it is open to any one to prove that they are not laws, if he can break them with impunity. It would be the height of pessimistic fatalism to hold that men must always go on doing that which they hate, and which brings them to misery and ruin. Man is not bound for ever by habits contracted during his racial nonage; his moral, rational, and spiritual instincts are as natural as his physical appetites; and against them, as St. Paul says, 'there is no law,' Huxley's Romanes Lecture gave an unfortunate support to the mischievous notion that the 'cosmic process' is the enemy of morality. The truth seems to be that Nature presents to us not a categorical imperative, but a choice. Do we prefer to pay our way in the world, or to be parasites? War, with very few exceptions, is a mode of parasitism. Its object is to exploit the labour of other nations, to make them pay tribute, or to plunder them openly, as the Germans have plundered the cities of Belgium. War is a parasitic industry; and Christianity forbids parasitism. Nature has her own penalties for the lower animals which make this choice, and they strike with equal severity 'the peoples that delight in war,' The bellicose nations have nearly all perished.