 Though exchange value is recognized, "economic value" is not, in theory, dependent on the existence of a market and price and value are not seen as equal.This is complicated, however, by the efforts of classical economists to connect price and labor value.Karl Marx, for one, saw exchange value as the "form of appearance" ["Erscheinungsform"] of value, which implies that, although value is separate from exchange value, it is meaningless without the act of exchange, i.e., without a market.