Page:Principles of Political Economy Vol 1.djvu/220

198 of the subject does not arise from these theories, but from too confused a notion of the causes which, at most times and places, keep the actual increase of mankind so far behind the capacity.

§ 3. Those causes, nevertheless, are in no way mysterious. What prevents the population of hares and rabbits from overstocking the earth? Not want of fecundity, but causes very different: many enemies, and insufficient subsistence; not enough to eat, and liability to be eaten. In the human race, which is not generally subject to the latter inconvenience, the equivalents for it are war and disease. If the multiplication of mankind proceeded only, like that of the other animals, from a blind instinct, it would be limited in the same manner with theirs; the births would be as numerous as the physical constitution of the species admitted of, and the population would be kept down by deaths. But the conduct of human creatures is more or less influenced by foresight of consequences, and by impulses superior to mere animal instincts: and they do not, therefore, propagate like swine, but are capable, though in very unequal degrees, of being withheld by prudence, or by the social affections, from giving existence to beings born only to misery