> This slippage is congnized by Marx in his terminology "socially necessary" or "social necessaries", I think.
> By the way, it impliedly includes the "family" in Marx , I think because the bourgeois know that the "race of laborers" must be perpetuated. Marx even has a measure of the number of years that the capitalist wants to get out of the worker before working him to death, based on fresh flesh produced in that family.
> Anyway, as you say the necessaries, the specific combination of use-values that meet physiological needs, derivative necessaries ( such as a car or transportation to get to work), and "normal" wants that derive from "fancy" (recreation , et al.) , is socially and historically determined in Marx's model. I think Marx's point would be that a reasonable estimate of this can be made concretely in each historical and social context, as you sketch the beginning of above. And Marx definitely recognizes that the definition of this is subject to class struggle as part of its social determination.
> This value of labor power is real and objective. In fact, its social determination makes it objective, that is outside the subjectivity of individuals. When you say "real" I am not sure what you mean. It is not a fantasy. The laborer and the labor power exist in objective reality. They are not just in someone's mind. The social is human ,but it is also real and objective.
> I'd say that Marx's mystification or point of an unexamined presumption is the notion that labor power is the only force of production that is able to add more value to the commodity produced than the value that went into producing it. Why does labor power have this "magic" power ?
Marx's argument is straightforward. The means of production (raw material and "instruments of labor") does not undergo any quantitaive alteration in production. They enter as the cost of their reproduction, and Marx calls them, for that reason constant capital. Otoh, productive labor does undergo an alteration in value in production, which is why he calls it variable capital.. It both produces the equivalent of its own value, and also an excess, surplus value, which itself varies according to circumstance. Surplus value is the measure of labor's exploitation. (see Capital, vol.1, chap 8, p.209)
> In the "family", is it not the labor of the wife, typically, that produces the laborers' labor power ? Both the husband's day-to-day, and the children of the "race of laborers" ? The labor power of a laborer is produced through many years in child care, with "building blocks", proto-stages that are necessary premises to the fully operable labor power of adults. Teaching a child to speak is a fundamental aspect of labor power produced by child care, for example.
True, Charles. But Marx includes the cost (value) of education and development of labor in his concept of social subsistence need. The fault lies in those of us making use of that concept today. Not only is measurement of social subsistence often neglected as an analytical concept, but when it is done, it typically only includes things like food, housing, transportation, etc.
> Thus, the answer to Marx's mystification is that the unpaid laborer of the wives (typically) is a major source of the ability of labor power to add more labor to the commodity than the value of the commodities that were "fed" to the laborer. The cooking, housekeeping, shopping, etc. that is unpaid are labors that produce the use-value of the labor power,but they are not counted as adding value to the labor power. They are a main source of the oversaturated value potency of labor power.
> The other way Marx says it is that labor power is the only source of NEW value in the production process ( all other forces of production can only add as much value as was added to them). Caring labor is the only source of the only source of (no typo) new value.
> This a feminist critique of Marx's labor power concept.
True enough, Charles. You not only need to buy food, housing, etc., but the cost of cooking cleaning, etc. are part of a subsistence need as well. Again Marx explicitly, not implicitly, based his concept on the needs of a worker's family, in order to reproduce the "race" of labor (he does say race, not class).
As to your general point about social subsistence: Different levels of economic and social development across different societies, and across time within the same society, result in different levels of social subsistence needs. There is no "slippage" as such. This allows capitalists, using essentially the same mode and means of production, to pay different wages as they try to drive wages toward subsistence in each situation, via class struggle in the labor market bargain. This is probably the clearest explication of why wages have nothing to do with labor's marginal product, as neoclassical economists would have you believe.