Capital is not then defined just by exploitation (which occurred in many precapitalist societies), but by its necessary drive to selfexpansion. The motivation for production and exchange is increasing the amount of value in the hands of the capitalist firma process for which some Marxist writers use the (in my view confusing) neologism "valorisation" .32
So the system is not just a system of commodity production; it is also a system of competitive accumulation. This creates limits to the action possible not only for workers, but also for capitalists. For if they do not continually seek to exploit their workers as much as is practically possible, they will not dispose of the surplus value necessary to accumulate as quickly as their rivals. They can choose to exploit their workers in one way rather than another. But they cannot choose not to exploit their workers at all, or even to exploit them less than other capitalists do-unless they want to go bust. They themselves are subject to a system which pursues its relentless course whatever the feelings of individual human beings.
Surplus value, accumulation and the rate of profit
Machines and raw materials do not themselves create value. Only the exercise of human labour has added to the natural wealth that existed in a state of nature and only continued human labour can increase it still further. Machines and raw materials exist because human labour has been applied in the past and they cannot substitute for it in the creation of new value. But they are necessary if labour is to achieve the average level of productivity prevailing in a particular society at a particular time. The final value of goods produced has to include an element covering the cost of the machines and materials used.
When a company produces cloth by employing workers to work on power looms that weave wool, the price of the final product has to cover not only the cost of providing the labour power of the workers (their wages) and the profit of the company, but also the cost of the wool and the wear and tear to the power looms. If the power loom can keep going for ten years, then in each year one tenth of its cost has to be covered by the annual sales of the cloth-this is what accountants refer to the depreciation costs of capital. Or, to put it another way, the labour incorporated in the value of the cloth includes not only the new socially necessary labour expended by the workers, but also the "dead labour" used to produce the wool and one tenth of the power loom.
Marx's Concepts
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