“How, ‘then, does a sum of commodities, of exchange values, become #capital?
Thereby, that as an independent social power, i. e., as the power of a part of society, it preserves itself and multiplies by exchange with direct, living labor-power. The existence of a class which possesses nothing but the ability to work is a necessary presupposition of capital. It is only the dominion of past, accumulated, materialized labor over immediate living labor that stamps the accumulated labor with the character of capital. Capital does not consist in the fact that accumulated labor serves living labor as a means for new production. It consists in the fact that living labor serves accumulated labor as the means of preserving and multiplying its exchange value.”

― Karl #Marx, Wage Labour and Capital