60 SOCIAL SCIENTIST the rate of profit itself evolved in a historical process through trading practices in Venice, Genoa and Asia Minor. Earlier, Engels ^teals exten--sively with the problem of how the law of value holds good in a system in which the labourer owns his own means of production and how in such a situation the volume of profit pet worker tends to be equal irrespective of differences in the values of capital employed by different workers. According to Marx, irrespective of the factors determining prices of production, The law of value dominates price movements with reductions or increases in required labour time making prices of production fall or rise. It is in this sense that Ricardo (who doubtlessly realised that his prices of production deviated from the value of commodities) says that "the inquiry to which I wish to draw the reader's attention relates to the effect of the variations in the relative value of commodities and not in their absolute value.4 (emphasis added) In dealing with this issue Marx clearly refers to relative prices and states that even where prices correspond to equal rate of profits, relative prices are still influenced and dominated by relative changes in values, that is to say, labour costs. I cannot see how objection can be taken to this statement in which there is no reference to absolute values at all. Are not relative prices influenced by changes in costs even when they yield equal rates of profit ? Joan Robinson unnecessarily accuses Marx of dogmatism which implies that after establishing the law of value in the opening chapters of Volume I (much before he starts elaborately analysing the features of capitalist production) Marx establishes the law of the equalisation of the rate of profit in Volume III without realising that the two laws contradict each other except in cases where the organic composition of capitals in certain industries coincides with the average composition for industry as a whole. This accusation is unfounded as the foregoing quotations abundantly clarify. While expressing views on value and price Joan Robinson refers to a slip which Marx made when he tried to show the relation between values and prices ofparticular commodities. Marx, according to her, forgot that "the elements of constant capital required for the production of a commodity enter into the calculation in terms of their prices, not of their labour values"5. What precisely is the position in this case ? Here is what Marx has to say in this connection in his chapter on the "Effect of Price Fluctuations". But in general, it should be noted here, as in the previous case, that if variations take place, either due to savings in constant capital, or due to fluctuations in the price of raw materials, they always affect the rate of profit.® In further elucidation of the effects of changes in the prices of the elements of constant capital, Marx says: The value of raw and auxiliary materials passes entirely and all at