Marx did not develop a specific theory of population growth, but highlighted some aspects in his theories of capitalism. He posited that under capitalism there are two main economic classes - the bourgeoisie (capitalists, owners) and the proletariat (workers, non-owners). The bourgeoisie profits by exploiting the labor of the poor proletariat. The proletariat would have more children to increase their labor force and income, leading to growth in the poor population. However, advances in production technology would render some of this increased population unemployed, creating misery and driving the class struggle that would ultimately replace capitalism with communism.