„We have just seen that, apart from money-capital, circulating capital is only another name for commodity-capital. But to the extent that labour power circulates in the market, it is not capital, no form of commodity-capital. It is not capital at all; the labourer is not a capitalist, although he brings a commodity to market, namely his own skin.“
— Karl Marx German philosopher, economist, sociologist, journalist and revolutionary socialist 1818 - 1883
Vol. II, Ch. X, p. 211.