I don't know where Fred gets these ideas from. The diversion of natural
prices from value ratios has been admitted by Ricardo in the very
beginning. And it is known as the first modification of the labor theory of
value. As a matter of fact if commodities exchanged according to their
value ratios, then a change in the wage rate will have no impact on the
relative prices of the commodities, and so Ricardo's perennial problem
would not even arise. The problem of the 'invariable measure of value'
arises simply because equalization of the rate of profit implies that the
labor theory of value cannot be strictly valid. Cheers, ajit sinha