: Surplus value is not a capitalist invention. It existed then.
Right. But wasn't this really surplus produce extraction (e.g. rent, taxes, interest, etc.)? I always thought surplus value extraction was peculiar to the predominance of wage labor and generalized commodity production.
: The value is always in the production. It cannot be in the circulation. See Marx's refutation of 'Say's Law.'
Right again. And yet Marx says in Capital (Vol. III, p.329): "Since the movement of merchant's capital is M-C-M', the merchant's profit is made, first, in acts which occur only within the circulation process, hence in the two acts of buying and selling; and, secondly, it is realised in the last act, the sale." Needless to say, old Charlie's got me on the ropes again.