Malthus, in the 1826 edition of his Essay on Population, attempted to discover 'the only effectual mode of improving the condition of the poor'. He was certain that any attempt to increase output faster than population growth was bound to fail, for the powers of reproduction could always keep pace with the supply of commodities, and there would be no long-term improvement in the condition of the poor. The alternative was to concentrate on slowing down the growth of the population, so that there was more for everyone and the condition of the poor would improve. There was, he suggested, a race between the tortoise of output and the hare of population, and only one effective means of raising the standard of living: 'If we can persuade the hare to go to sleep, the tortoise may have some chance of overtaking her.' 1
Was Malthus guilty of exaggerating the difference in the speed of the contestants? Perhaps the hare was less speedy than he assumed, for there were biological constraints on both births and deaths which set limits to the rate of population growth. The level of mortality was high, especially for infants, in an age before public health and medicine had conquered disease, and life expectancy was low. Although there was no effective birth control other than abstinence and celibacy, women could bear only a limited number of children between menarche and menopause, a period of at most thirty years which was reduced by the late age of marriage in European societies. The population in such circumstances was rarely capable of growing at more than about 1.5 per cent a year. Most estimates place the annual rate of growth of the gross national product in the eighteenth century at considerably below 1 per cent, so that population certainly had the capacity to outstrip production at least two- and probably threefold. Population growth much above 0.5 per cent a year would be likely to strain output and threaten the standard of living, and the major determinant of prosperity was society's ability to hold back or to release its full potential of population growth.