Shane Mage:
> Engels is talking about "barter." What can justify equating *barter* with > "a historical stage of simple commodity production?"
You should have read further:
"In a word: the Marxian law of value holds generally, as far as economic laws are valid at all, for the whole period of simple commodity production — that is, up to the time when the latter suffers a modification through the appearance of the capitalist form of production. Up to that time, prices gravitate towards the values fixed according to the Marxian law and oscillate around those values, so that the more fully simple commodity production develops, the more the average prices over long periods uninterrupted by external violent disturbances coincide with values within a negligible margin. Thus, the Marxian law of value has general economic validity for a period lasting from the beginning of exchange, which transforms products into commodities, down to the 15th century of the present era. But the exchange of commodities dates from a time before all written history — which in Egypt goes back to at least 2500 B.C., and perhaps 5000 B.C., and in
Babylon to 4000 B.C., perhaps to 6000 B.C.; thus, the law of value has prevailed during a period of from five to seven thousand years."