Thomas Malthus was an 18th-century British philosopher, economist and statistician. He is best known for his Malthusian growth model, a formula used to project population growth. His theory suggests that population growth will always outpace production of food, resulting in crises such as war, famine and disease.

Malthus was active in the Statistical Society of London, which he had founded, and was an avid proponent of economic, political and social reform. He viewed the continuous growth of population, unchecked by moral restraint, as a pervasive and destructive force. In this way, Malthusian growth has long been a famous, if not particularly well-liked, model of population dynamics.

The most widely known version of Malthus’ theory is that population growth tends to expand in geometric proportions while food production will increase at an arithmetic rate. Because of this, it is impossible for food production to continue to meet the needs of the growing population. Thus, in the absence of preventive measures, famine and an overall decrease in the quality of life is inevitable.

His theory was later used to justify British colonial policies that aggravated the Irish Potato Famine. More recently, it has been largely discredited by the onset of modern industrialized farming techniques, which allowed for much faster production of food than Malthus could have anticipated.

Notwithstanding, Malthus made a crucial contribution to social economics by introducing a theory of population growth that would go on to powerful ideas such as the Malthusian Catastrophe and Zero Population Growth. His theories brought greater awareness to humans’ responsibility towards their environment and were important in highlighting the focus on moral restraint, particularly in regard to issues such as birth control and poverty reduction. Nevertheless, Malthus' legacy is still a controversial topic of debate in economic and social circles.