"Exactly a year before Nassau W. Senior discovered at Manchester, that the profit (including interest) of capital is the product of the last hour of the twelve, he had announced to the world another discovery. 'I substitute,' he proudly says, 'for the word capital, considered as an instrument of production, the word abstinence.'"
[In a footnote:] "It has never occurred to the vulgar economist to make the simple reflexion, that every human action may be viewed, as 'abstinence' from its opposite. Eating is abstinence from fasting, walking, abstinence from standing still, working, abstinence from idling, idling, abstinence from working, &c." -- K. Marx, CapitalMarx's footnote casually suggests a fertile potential that he didn't follow up on. I propose to use Veblen's notion of "conscientious withdrawal of efficiency" (or sabotage) and Robert Hale's "coercion" to outline what might be termed a "labour/abstinence theory of value" that avoids the pitfalls both of the misplaced concreteness of "embodied" labour and the unreal passivity of the equilibrium view of supply and demand.
Living labour-power is the consummate numéraire good because it is definitively limited by population and physiology at any given time while still being flexibly expandable. Keynes suggested as much in arguing that "we have been able to take the unit of labour as the sole physical unit which we require in our economic system, apart from units of money and of time."
By contrast, there are no such limits on the quantity of labour "embodied" in commodities, including physical capital. However, the value of such embodied labour is subject to depreciation due to obsolescence, wear and tear and over-accumulation (or excess capacity). So the first contrast between living labour power and labour embodied in capital goods is that the former is relatively fixed and the latter is indefinitely expandable -- at least in principle.
But there is also a second contrast, having to do with the perishability of living labour power. The worker who is unable to dispose of his or her capacity to work today can't put "yesterday's labour power" on the market tomorrow. It's gone. The penalty for not being able to immediately sell goods is not as final and can even sometimes result in a windfall. The same distinction applies equally to the conscientious withdrawal from the market.
Thus living labour power is a more or less definitive quantity that is disciplined by its perishability for a temporary withdrawal from the market, while labour embodied in capital goods is, in principle, indefinitely expandable and potentially rewarded by temporary withdrawal (abstinence) from the market. "Abstinence," then, makes its re-entry not in the form of a pious moral justification for profit but of a strategy for leveraging profitability by regulating the "scarcity" of capital relative to labour power.
"Value," in this account is not some mechanical adding up of units of labour power expended and/or embodied. Nor is it the passive intersection of complementary subjective utility functions. Instead it is the outcome of a "higgling of the market," to use Thornton's phrase, constrained by the properties of the labour-power numéraire. Thus it is constituted, in part, by labour-power and embodied labour but alternatively by the withholding of labour-power and embodied labour -- that is by abstinence of production, not in consumption.
The case for such a labour/abstinence theory of value can best be explained by arguing against competing interpretations that address elements of this argument but come to different conclusions. My foils will be Ludwig von Mises and John Roemer, for reasons which should become readily apparent.