" This leaves us with the logical rationale, which I find much more persuasive. It focuses on the methodology at work as the argument unfolds: the dialectical and relational opposition between use-value and exchange-value as embodied in the commodity; the externalization of that opposition in the money-form as a way to represent value and facilitate commodity exchange; the internalization of this contradiction by the money-form as both a medium of circulation and a measure of value; and the resolution of that contradiction through the emergence of relations between debtors and creditors in the use of money as a means of payment. "

― David Harvey , A Companion to Marx's Capital