A strange political economy; the only one, nevertheless, that ever was or can be: all political economy founded on self-interest[62] being but the fulfilment of that which once brought schism into the Policy of angels, and ruin into the Economy of Heaven. [62] "In all reasoning about prices, the proviso must be understood, 'supposing all parties to take care of their own interest.'"--Mill, III. i. 5. "The greatest number of human beings noble and happy." But is the nobleness consistent with the number? Yes, not only consistent with it, but essential to it. The maximum of life can only be reached by the maximum of virtue. In this respect the law of human population differs wholly from that of animal life. The multiplication of animals is checked only by want of food, and by the hostility of races; the population of the gnat is restrained by the hunger of the swallow, and that of the swallow by the scarcity of gnats. Man, considered as an animal, is indeed limited by the same laws: hunger, or plague, or war, are the necessary and only restraints upon his increase,--effectual restraints hitherto,--his principal study having been how most swiftly to destroy himself, or ravage his dwelling-places, and his highest skill directed to give range to the famine, seed to the plague, and sway to the sword. But, considered as other than an animal, his increase is not limited by these laws. It is limited only by the limits of his courage and his love. Both of these _have_ their bounds; and ought to have: his race has its bounds also; but these have not yet been reached, nor will be reached for ages.