 by labour (quite like the value-part added to the product by raw material, instruments of labour, etc., in short, by all the material components of constant capital) is equal only to the value of the means of subsistence paid to the labourers and necessarily consumed for the maintenance of their ability to function as labour-power. Their very doctrine stands in the way of their discovering the distinction between constant and variable capital. If it is labour that produces surplus-value (in addition to reproducing its own price), then it does so in industry as well as in agriculture. But since, according to their system, labour produces surplus-value only in one branch of production, namely agriculture, it does not arise out of labour but out of the special activity (assistance) of nature in this branch. And only for this reason agricultural labour is to them productive labour, as distinct from other kinds of labour.
Adam Smith classifies the means of subsistence of labourers as circulating capital in contradistinction to fixed capital:
1) Because he confuses circulating as distinguished from fixed capital with forms of capital pertaining to the sphere of circulation, with capital of circulation — a confusion uncritically accepted. He therefore mixes up commodity-capital and the circulating component of productive capital, and in that case it is a matter of course that whenever the social product assumes the form of commodities, the means of subsistence of the labourers as well as those of the non- labourers, the materials as well as the instruments of labour themselves, must be supplied out of the commodity capital.
2) But the physiocratic conception too lurks in Smith’s analysis, although it contradicts the esoteric — really scientific — part of his own exposition.
Generally speaking the advanced capital is converted into productive capital, i.e., it assumes the form of elements of production which are themselves the products of past labour. (Among them labour-power.) Capital can function in the process of production only in this form. Now, if instead of labour-power itself, into which the variable part of capital has been converted, we take the labourer’s means of subsistence, it is evident that these means as such do not differ, so far as the formation of value is concerned, from the other elements of productive capital, from the raw materials and the food of the labouring cattle, on which ground Smith in one of the passages quoted above places them, after the manner of the physiocrats, on the same level. The means of subsistence cannot themselves expand their own value or add any surplus-value to it. Their value, like that of the other elements of the productive capital, can re-appear only in the value of the product. They cannot add any more to its value than they have themselves. Like raw materials, semi-finished goods, etc., they differ from fixed capital composed of instruments of labour only in that they are entirely consumed in the product (at least as far as concerns the capitalist who pays for them) in the formation of which they participate and that therefore their value must be replaced as a whole, while in the case of the fixed capital this takes place only gradually, piecemeal. The part of productive capital advanced in labour-power (or in the labourer’s means of subsistence) differs here only materially and not in respect of the process of labour and production of surplus-value from the other material elements of productive capital. It differs only in so far as it falls into the category of circulating capital together with one part of the objective creators of the product ("materials" Adam Smith calls them generally), as opposed to the other part of these objective product creators, which belong in the category of fixed capital.
The fact that the capital laid out in wages belongs in the circulating part of productive capital and, unlike the fixed component of productive capital, shares the quality of fluency with a part of the objective product creators, the raw materials, etc., has nothing whatever t