I would like to underline shag's question. I have one suggestion, which doesn't answer trhe question but does set some parameters.
Postone does NOT for the most part allow for contingency. That is not an objection: focusing on contingency would impossibly jumble his analysis, and he correctly (as does Albritto focuses on capitalism at its most abstract -- and as did Marx. (Many of the really sloppy understandings of Capital come from those who more or less completely ignore his statement that the equivalen in a critique of political economy to experiments in science is ABSTRACTION.)
But though Postone writes at an abstract level, ignoring contingency, the reader needs to be aware that "Actually Existing Capitalism" actually exists in a context of non-0capitalist relations -- e.g., family life; e.g., schools; e.g., in fact, the state itself. Commodities do not get exchanged while a household is eating dinner; nor, despite the current efforts of the U.S. government, does the theory of value explain infantry tactics. All 'outside' capitalism, shaped by capitalism to its needs, but also shaping capitalism in the concret.
In the HM symposium on Postone (fucking aged-damaged short-term memory: this is a bit vague) one (negative) critic argues that workers are also humans; another, positive critic, growls that they aren' ALSO humans: they're humans who work. But when we view capitalism as a totality, workers are abstract, not particular. This is too sloppy and I'll try to come back to it in another post. But I do think "totality" is more graspable if we keep remembering that it is only at a highly abstract level that the concept holds.
Carrol