Marx explains the condition of the proletariat through oppression and lack of class consciousness - that magic feeling that the group of people - proletariat - shall get in order to understand their role in society and change their condition. To Marx, bourgeoisie controls proletariat through alienation - stripping away any human characteristics from the job, the process and the living.

I think this is fairly vivid: "The bourgeoisie has stripped of its halo every occupation hitherto honoured and looked up to with reverent awe. It has converted the physician, the lawyer, the priest, the poet, the man of science, into its paid wage labourers."

What he means is that as an outcome of the new developments in technology and industrial growth, the establishment of new economy, known human relationships became substituted by commodity or money relationships. That is, a human worth started being measured in one's income rather than in one's input. Additionally, mass production has broken down all complex crafts into simplified, unexciting parts that could be done by anyone, thus, turning people into commodities themselves. Deskilling, dull labor is cheaper than complex, interesting and rare talent.

Therefore, in the process of industrialization the human factor got lost. People lost their individuality, their skill and their worth, other than their worth in the wage they are paid. It is hard to change the world with such attributes.

Now, what's up with the middle class? The middle class is weak in comparison to the large, mass-producing factories. Think now - local small business vs Walmart, for example, same situation, different century. To his prediction, most middle class doesn't have the resources to rise higher, so they can only sink lower. Therefore, even existing and breathing, the middle class does not have any specific force to
create social change.

So, to Marx, it is up to the proletarians to find a way to take what rightfully belongs to them. And he doesn't just mean money, he means life with human dignity, that is not stripped of its essential elements - creativity, individualization, meaning in daily work, etc.

Marx, K.(1982). The Communist Manifesto. Harmondsworth Eng: Penguin Books.

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