Although Marx did not give theory of population but ideas were implicit in his political theory of communism where population growth was part of process that encouraged capitalism bases disparities. As per Marx, solution of population problems like population growth and poverty lies in adopting socialist model of social organisation.
His theory is about how nature and mode of production change through time, that’s why considered as historical approach too. It’s a theory in political science where power is determined by who owns the mode of production.
Capitalism and its twin evils of profit and private property encouraged the rich capitalist to accumulate capital and profits by exploiting the workers while the labour and working class have incentives in accumulating their numbers because ‘there hands were the basis of their existence’.
Industrial Revolution => capitalism => private property & profit => exploitation of labour class => inequality/ disparity => population growth of poor => Poverty
As the capitalist attempted cost cutting by laying off labour, paying progressively lesser wages, introducing machines; the labour in it’s poverty would try accumulating more and more hands and as part of a vicious circle would render itself increasingly excessively & make themselves all the more poor.
This capitalism induced disparities and exploitation become the cause of population growth with predominant in labour class.
The solution offered for managing population growth and poverty according to Marx was redistribution of resources and equitable ownership of modes of production. In fact unlike Demographic Transition Model theory & Malthusian theory, Marx is not so much concerned by size and growth rate of population. He is more concerned about social inequalities & class differences in which poverty has its routes.
It is one of the earliest instances where population & the numbers were considered as strength. Marx suggested workers to unite and use their numbers to effect overthrow of capitalist exploits.
Although there are debates about universal validity of Marxian ideas where poverty is blamed on capitalism, Marx however was a dominant influence for a good part of 20th century, at least till the collapse of USSR. The most important contribution of Marx interpretation lies in incorporating socialist welfare objective which continue to be basis of most of the population development objectives.
Marx overemphasized and considered private property as the main cause of all evils including poverty, misery, unemployment and fast growth of population. In reality social norms, educational level, technological advancements and attitude towards family are all vital determinants of population growth.
Some appreciation please!