Marx’s Economic Manuscripts of 1861-63
1) Transformation of Money into Capital
Labour capacity has a specific character and is therefore a specific commodity — just as money was both a commodity in general and a specific commodity, though with money its specific character was produced by the way all commodities related to any commodity which happened to be chosen as the exclusive commodity, whereas here it is produced by the nature of the commodity’s use value — but despite this it is like every other commodity 1) a use value, a particular object whose use satisfies particular needs, and 2) it has an exchange value, i.e. a definite quantity of labour has been used up, objectified, in it as object, as use value. As objectification of labour time in general it is value. The magnitude of its value is determined by the quantity of labour used up in it. This value, expressed in money, is the price of labour capacity. As we are proceeding here from the presupposition [I-26] that all commodities are sold according to their value, price is in general distinguished from value only by the fact that it is the value estimated or measured or expressed in the material of money. The commodity is therefore sold at its value when it is sold at its price. Similarly, one should understand under the price of labour capacity nothing but its value expressed in money. The value of labour capacity for a day or a week is therefore paid when the price of the means of subsistence required for the maintenance of labour capacity during a day or a week is paid. This price or value, however, is not just determined by the means of subsistence entirely consumed by labour capacity each day, but equally by the means of subsistence it makes use of each day, such as clothes, for example, but does not entirely use up each day thereby necessitating their constant renewal; they therefore need to be renewed or replaced only over a certain period of time. Even if all objects relating to clothing were only used up once within one year (vessels for eating and drinking, e.g., do not need to be replaced so quickly as clothing, because they do not wear out so rapidly, and this applies still more to furniture, beds, tables, chairs, etc.), the value of these articles of clothing would still be consumed during the whole year for the maintenance of labour capacity, and the worker would have to be able to replace them after the end of the year. He would therefore have to receive every day on an average an amount such that after deduction of the daily expenditure for daily consumption enough was left over to replace worn-out clothing by new after the year had run its course; hence a daily requirement of, if not the such and such portion of a coat, at least one day’s aliquot part of the value of a coat. The maintenance of labour capacity, if it is to be continuous, which is a prerequisite with the capital-relation, is not determined only by the price of the means of subsistence consumed in a day and therefore to be renewed, replaced on the next day: there must also be added the daily average of the price of the means of subsistence which need replacing over a longer period of time but must be used every day. It amounts to a difference in payment. A use value like a coat, for example, must be bought as a whole and used up as a whole. It is paid for by holding in reserve every day 1/x of the price of labour.
Since labour capacity is available only as an ability, an aptitude, a power enclosed in the living body of the worker, its maintenance means nothing other than the maintenance of the worker himself at the level of strength, health, vitality in general, which is needed for the exercise of his labour capacity.
[I-27] We must therefore state the following:
The commodity the worker offers for sale on the market in the sphere of circulation, the commodity he has to sell, is his own labour capacity, which, like every other commodity, has an objective existence so far as it is a use value, even if it is here only an ability, a power in the living body of the individual himself (it is hardly necessary to mention here that the head belongs to the body as well as the hand). Its functioning as a use value, however, the consumption of this commodity, its use as a use value, consists in labour itself, just like wheat, which only really functions as a use value when it is used up in the nutrition process, when it takes effect as an alimentary substance.
The use value of this commodity, like that of every other commodity, is only realised in the process of its consumption, hence only after it has passed from the hand of the seller into that of the buyer, but it has nothing to do with the process of sale itself except that it is a motive for the buyer. This use value, which exists as labour capacity before it is consumed, has in addition an exchange value, which, as in the case of every other commodity, is equal to the quantity of labour contained in it and therefore required for its reproduction; and as we have seen it is exactly measured by the labour time required to create the means of subsistence necessary for the maintenance of the worker. Time is the measure for life itself, just as e.g. weight is the measure for metals; hence the labour time required on an average to keep the worker alive for one day would be the daily value of his labour capacity, by virtue of which it is reproduced from one day to the next, or, what is the same thing here, preserved under the same conditions. As we have already said, the range of these conditions is not prescribed by simple natural need but by natural need historically modified at a certain level of civilisation.
This value of labour capacity expressed in money is its price, and we presuppose that it is paid, since we in general assume that equivalents are exchanged or that commodities are sold at their value. This price of labour is called the wage. The wage which corresponds to the value of labour capacity is its average price, as we have explained it b; it is the average wage, which is also called the minimum wage or salary, whereby we understand by minimum not the extreme limit of physical necessity but the average daily wage over e.g. one year, in which are balanced out the prices of labour capacity during that time, which now stand above their value, and now fall below it.
It lies in the nature of this particular commodity, labour capacity, that its real use value only really passes from one hand to the other, from the hand of the seller to that of the buyer, after it has been consumed. The real use of labour capacity is labour. But it is sold as a capacity, a mere possibility before the labour has been performed, as a mere power, whose real manifestation only takes place after its alienation to the buyer. Since here the formal alienation [by sale] of the use value and its actual handing over are not simultaneous occurrences, the money of the buyer in this exchange mostly functions as means of payment. Labour capacity is paid for daily, weekly, etc., but not at the moment when it is bought, rather after it has really been consumed in a day, a week, etc. In all countries where the capital-relation is developed the worker’s labour capacity is only paid for after it has functioned as such. In this connection it can be said that everywhere the worker gives credit to the capitalist, by the day or by the week; this is due to the special nature of the commodity he is selling. The worker hands over to him the use of the commodity he sells, and only receives its exchange value or price after it has been consumed. //In times of crisis, and even with isolated bankruptcies, it is then revealed that this credit given by the workers is no mere phrase, since they do not get paid.// Nevertheless this does not initially alter the exchange process. The price is laid down by contract, hence the value of labour capacity is estimated in money, although it is only realised, paid, later. The determination of price is therefore related to the value of labour capacity, not the value of the product which accrues to the buyer of labour capacity as a result of its consumption, its actual utilisation. Nor is it related to the value of labour, which is not a commodity as such.
[I-28] We now know in fact what is paid to the worker by the owner of money who wants to transform his money into capital, and therefore buys labour capacity: he in fact pays him e.g. the daily value of his labour capacity, a price or daily wage corresponding to its daily value, in that he pays him a sum of money = the value of the means of subsistence necessary to the daily maintenance of labour capacity; a sum of money which represents exactly as much labour time as is required for the production of these means of subsistence, i.e. for the daily reproduction of labour capacity.
We do not yet know what the buyer receives for his part. It is bound up with the specific nature of this commodity, labour capacity, and with the specific purpose of its purchase by the buyer — namely that he may prove himself as representative of self-valorising value — that the operations occurring after the sale are of a specific nature and must therefore be considered separately. In addition — and this is the essential point — the specific use value of the commodity and its realisation as use value concern the economic relationship, the determinate economic form itself, and are therefore relevant to our analysis. It can be pointed out here in passing that use value originally appears as a matter of indifference, as any material prerequisite one cares to choose. In the analysis of the commodity the real use value of the individual commodities is completely irrelevant,  and the same therefore holds for the specific character of the commodities altogether. What is alone important here is the general distinction between use value and exchange value, out of which money develops, etc. (See above.) // What the worker has in fact sold to the money owner is the disposition over his labour capacity, and the latter has to employ it in accordance with its nature, its specific character. Within what limits, will be seen later. // [I-28].