Discuss the theory of optimum population.

The term 'optimum' refers to a condition which is most favourable. This could be temperature, climate, light, population or anything else. Till the time of Malthus, most theories of population were based on social or biological factors. Soon, however, economists realized that besides social and biological factors, economic factors are also responsible for change in population. Therefore, the optimum population theory was formulated to study the correlation between population and national income. There is no exact reference as to who invented this theory. Some believe it had its origins in the writings of Karl Winkelblech (1810-1865), a German professor who classified nations according to population into three categories—under-populated, over -populated and normal populated. Edward West's Essay on the Application on Capital to Land (1815) also throws light on the impact of growth of population on the growth in production. The fundamental idea in the theory of optimum population was used by Henry Sidgwick. He did not use the term optimum, but his indication in the writing was for the same. Later on, the term 'optimum' was systematically used by Edwin Carman, Hugh Dalton and A.M. Carr Saunders.

According to Edwin Cannan, 'at any given time, the population which can exist on a given extent of land, consistent with the greatest productiveness of industry at that time is definite'.

According to the United Nations, 'the concept of optimum population is the size of the population which results in the highest per capita income, the highest productivity as measured in different mariners, or the highest level of other less well-defined economic indicators, such as economic welfare, level of living, real income, and in some cases employment'.