There is no class in between the proletariat (workers) and bourgeoisie (capitalists).
Proletariat - taken from a Latin term for the "Lowest" working class of Rome, by way of the French version of it.
Marx called the middle class "petty bourgeoisie" or "petty capitalists." Marx largely ignored the middle class since he saw society as being divided into owners and controllers of the means of production and the common worker. According to him, the middle class was comprised of doctors, lawyers, architects and other professionals as well as small business owners. He believed that the middle class had at best a neglible effect on the forces of materialism as they shaped society. The middle class were only "petty bourgeoisie because they did not own the means of production and so were not truly part of the bourgeoisie. Nor were they common workers therefore they were not truly part of the proletariat. He called them petty bourgeoisie because they tended to aspire to be more bourgeois than proletarian and had more characteristics in common with the bourgeoisie than with the proletariat.
The Proletariat is a social class composed of common workers who own nothing but the right to sell their own labor. They are the ones exploited and oppressed by the bourgeoisie so that they can accumulate wealth at the expense of the proletariat. Karl Marx was the first person to use the term proletariat to refer to the class of common workers and to urge them to unite in order to overthrow their bourgeoisie masters. Lenin included soldiers and peasant farmers in the proletariat and urged them all to unite and overthrow the Tsarist regime and its capitalist economy and afterward to establish a socialist economy and a government run by and for the benefit of the proletariat. Unfortunately for the workers, soldiers and peasants, by "proletariat", Lenin essentially meant members of the Communist Party.
Bourgeoisie
Of course. Don't you? It's believed by capitalists too, but they argue it's a necessity because it keeps economy running. Marxists call this division "class struggle", and these classes are: the bourgeoisie (the owners of the means of production) and the proletariat (the workforce).
Karl Marx referred to the owners of capital as the bourgeoisie, who controlled the means of production and exploited the labor of the proletariat, the working class. Marx critiqued the capitalist system for perpetuating inequality and alienation between these two social classes.
Although Karl Marx called members of the upper class the "bourgeoisie," the two terms are not synonymous. The bourgeoisie are the people who own and control the means of production, not just the upper class. People may be in the upper class if they are wealthy like professional people and shopowners, but they are not part of Marx's bourgeoisie, because they do not own the means of production of good and they don't employ workers in factories. Likewise, the term "proletariat" does not equate exactly to the "lower class."
Marx criticizes the bourgeoisie and capitalism for creating a system that exploits the working class, or proletariat, by prioritizing profit over human welfare. He argues that capitalism leads to alienation, as workers become disconnected from the fruits of their labor and their true human potential. Additionally, Marx contends that the bourgeoisie perpetuates inequality and class struggle, ultimately destabilizing society and leading to its own downfall. This critique forms the basis of his call for a revolutionary transformation towards a classless society.
Marx's Communist Manifesto called for the overthrow of capitalist societies and the establishment of a classless, communist society. It emphasized the struggle between the proletariat (working class) and the bourgeoisie (capitalist class) as a driving force of historical progress. The manifesto urged workers of the world to unite and rise against their oppressors, advocating for collective ownership of the means of production to eliminate class distinctions.
Marx referred to the dictatorship of the proletariat as a temporary transitionary phase during which the working class seizes control of the state to dismantle capitalism and establish a socialist society. In this phase, the proletariat holds political power to reshape the economic system and ultimately achieve a classless society.
Word salad. Ack. It's Karl Marx, by the way. And he didn't do anything for capitalists. He was opposed to capitalism. Some people even go so far as to call him the "father of modern communism".
The industrial revolution led to a new economic group of people we now call the middle class. The progressive movement found it's popularity in the middle class.