Final answer:
Thomas Malthus theorized that uncontrolled population growth would surpass the food supply, leading to poverty, famine, and subsequent population checks through mortality or reduced fertility.
Step-by-step explanation:
Thomas Malthus, an English clergyman and economist, proposed a theory that has come to be known as Malthusian theory. The core of Malthus' argument, presented in his seminal work, An Essay on the Principle of Population (1798), was that population growth tends to outrun the food supply, leading to inevitable poverty, famine, and misery unless checked by certain limiting factors. Malthus explained that population growth occurs exponentially, while food supply grows arithmetically; thus, without preventive measures, such as moral restraint (reducing fertility), or positive checks, like war, famine, and disease (which increase mortality), the population would reach unsustainable levels. Over time, this view influenced debates on public policy, economics, and social welfare, although subsequent historical developments have challenged its validity.
Malthus identified two types of checks that control population: positive checks, which increase mortality rates, and preventive checks, which lower birth rates. His ideas were considered controversial, particularly because they addressed topics such as birth control and moral restraint, seen by many at the time as antithetical to religious beliefs. Despite the controversy, Malthus' work has been influential in the study of population dynamics and resource management.