The system of Malthusian doctrines relating to population. See Malthusian.

Malthus' theory that population increase would outpace increases in the means of subsistence

The belief that population tends to increase faster than the means of subsistence (i.e. food supply, resources) and that population growth therefore must be slowed either by controlling fertility (preventive checks) or by disease, famine or war (positive checks). The term is named after Thomas Malthus, an English clergyman and economist, who propounded this argument in his Essay on the Principle of Population (1798). Note, Malthus was opposed to birth control as a means of slowing population growth, terming the practice a 'vice'. In his view, 'moral restraint' (late marriage and remaining chaste before marriage) was the only acceptable way of restricting fertility.