Ricardo and Marx versus Keynes
Ricardo, unlike Adam Smith, attempted to use the law of labor value consistently. He sensed that the law of labor value applied not only to simple commodity production but also to capitalism proper. Ricardo was not completely successful in this, but he was certainly on the right track. He realized that price is a relationship between two commodities, the commodities whose price is being measured and the money commodity—gold—in which the price of the commodity is reckoned.
According to the Ricardian law of labor value, market prices tend to fluctuate around an axis determined by the relative values of gold and the commodity whose value gold is measuring. Ricardo realized that a rise or fall in wages would affect the rate of profit but not the overall prices of commodities.
Marx developed Ricardo’s law of labor value further, resolving the contradictions that Ricardo himself was unable to overcome. However, even the Ricardian version of the law of labor value is quite sufficient to refute the claim of Keynes that wages determine prices.
As for Marx, he demonstrated in the first three chapters of volume I of “Capital” that price must always be measured in terms of the use value of the commodity that serves as the universal equivalent. Assuming gold is the money commodity, exchange value, or what comes to exactly the same thing, price, is always a certain quantity gold measured in terms of weight.
A Critique of Crisis Theory 