While The Communist Manifesto states the revolutionary aims of communism and maintains that capitalism must inevitably destroy itself, Das Kapital is Marx's analysis of the means of destruction. It is a critique of political economy which attempts to explain economics in coldly analytical and scientific terms. To Marx, his scientific arguments comprise irrefutable evidence prognosticating the doom of capitalism.
Marx sets the scene for his attack on capitalism by describing a capitalistic world of perfect competition — where the market is free, without monopolies, unions, or special advantages for anyone. Every product sells for its correct price or value. Agreeing with Adam Smith and David Ricardo on the definition of value, Marx states that the value of a product is the amount of labor which goes into making it. The worker wishes to sell labor-power; the capitalist wants a profit.
But how can there be profit if everything sells for an exact value?
It would be simple for profits to arise if there are monopolies to set excessive prices, or if capitalists pay less for labor than it is worth. Marx demonstrates that in its most perfect form capitalism is unworkable. Therefore capitalism, with its monopolies and imperfections, has no chance for survival.
Das Kapital explains that profits arise from one product or commodity which is distinctive — labor. Because capitalists control all access to the means of production, the worker must sell labor-power to the capitalist for its exact worth. Its value is what it takes to keep the laborer alive.
Marx concludes that labor actually produces more for the capitalist by working extra hours. The surplus value of labor gives rise to the capitalist's profits. In short, while the worker receives only a daily wage equal to subsistence requirements, actual production for a workday results in extra units of products. The value is translated into profits for the capitalist, who steals what is rightfully the worker's.
