The term capitalist refers to an economic category, and bourgeoisie is a social one, today the term bourgeoisie is often used as a word to describe the elite and upper class, and the lifestyle of these. .
"The essential condition of the existence and domination of the bourgeois class is the accumulation of wealth in the hands of private persons, the formation and augmentation of capital; the condition of Capital is wage labour".
The second class was the proletariat, this was the working class, and it describes the individual who is legally free, hence free labour but economically compelled to sell their labour onto the market. Marx described this class as being the main industrial workers, he also named them politically unimportant. Proletariat derives from the Latin meaning "those who's only property is their children", therefore this group have also interestingly existed in other types of societies such as slavery. Some therefore argue the point that Marx did not invent this class, but that it had already existed for many years previously. .
The relationship of the bourgeoisie and the proletariat was for Marx one of anguish. Marx describes the workers as "slaves of the bourgeoisie class, enslaved by the machine".
As technology became more and more efficient, the capitalist sought to increase the output, and therefore profit. This affected the proletariat in a negative way as they were still being paid the same wage but the capitalist was gaining increased profits thus higher surplus value thereby benefiting from cheap labour. Marx called this "exploitation", this also alienated humans from "species being" by this he meant that the workers were denied any possibility of their natural potential for creativity. The labour that the working class carried out to create a source of wealth for the bourgeoisie was often physically and mentally tedious and was often routine and boring.