Karl Marx explains in his "Capital" the necessity of the transformation of the price of labour-power into wages. But his explanation is not regarded as the demonstration of the necessity, for the reasons that on the assumption of the transformation he merely explains the affairs how this transformation reflects the idea of people in the bourgeois societies, and does not point out the objective bases of the transformation. These opinions are based on the confusion of objective reality with ideological and phenomenal form of it, or on the mechanistic interpretation of materialism: the ideal is immediate reflection of the material. Wages as "the price of labour" is no more than ideological and phenomenal form of the price of labour-power as objective reality. The necessity of such a thing should be explained not only by the material bases of it's existence but the subjective moments in the reflection of the material to thought. So "the necessity" given by K. Marx is an indispensable part of the necessity for such a description as he explains on the subjective moments. Then does K. Marx describe it without pointing out the objective bases of it? The fact is that he points them out from part I to part V in vol. I of his "Capital". And the key subject" of them is that "the exchange between capital and labour presents itself to the mind in .the same guise as the buying and selling of all other commodities", i. e. "the buyer gives a certain sum of money and the seller an article of a nature different from money", because the material moment of the circulation of commodities is the social circulation of matter. In most theories the objective basis is the deferred payment of wages or "the selling of labour" as the material overlook of the selling of labour-power. The former is one of the objective bases, but it only intensifies the phenomenon. From this point of view, the theory that the deferred payment of wages is the objective basis is insufficient. The latter is the imaginary expression itself, so it is not the objective basis. As this example, this theory is based on same mistakes. These theories come from the assumption that the imaginary expresion of "the price of labour" or the price of use-value of commodities haunts only the buying and selling of labour-power, and from this assumption they emphasize that the peculiarity results from the inseparability of labour-power from bodies of workers. But they are mistakes, for such expressions also haunt the buying and selling of all other commodities.