While the single commodity appeared from the standpoint of use-value as something independent, as exchange value it was regarded first of all in its relation to all other commodities. This relation was, however, merely theoretical, imaginary. It becomes real only in the process of exchange. On the other hand, a commodity _is_ an exchange value in so far as a certain quantity of labor-time has been expended on it, and it consequently represents _materialized labor-time_. But of itself it is only materialized individual labor-time of a particular kind, and not _universal_ labor-time. Therefore, it _is not_ directly an exchange value, but must first _become_ such. First of all, it is an embodiment of universal labor-time only in so far as it represents labor-time applied to a definite useful purpose, i. e., when it represents a use-value. This was the material condition under which alone labor-time contained in commodities was regarded as universal social labor. Thus, while a commodity can become a use-value only after it has been realized as an exchange value, it can, on the other hand, be realized as an exchange value only if it proves to be a use-value in the process of alienation. A commodity can be alienated as a use-value only to one whom it serves as a use-value, i. e., as a means of satisfying a certain want. On the other hand, it is exchanged for another commodity, or, if we put ourselves on the side of the owner of the other commodity, it, too, can be alienated, i. e., be realized, only if brought in contact with that particular want of which it is the object. In the universal exchange of commodities as _use-values_ the basis for their mutual relations is in their material difference as distinct objects which satisfy different wants by their specific properties. But as mere use-values, they are indifferent to each other, and are incommensurable. As use-values they can be exchanged only with reference to certain wants. They are exchangeable only as equivalents, and they are equivalents only as equal quantities of materialized labor-time, so that all regard to their natural properties as use-values and therefore to the relation of the commodities to particular wants is eliminated. On the contrary, a commodity is realized as an exchange value by replacing as an equivalent any definite quantity of any other commodity, regardless of whether it is a use-value for the owner of the other commodity or not. But to the owner of the other commodity it is a commodity only in so far as it is a use-value to him, and it becomes an exchange value to its owner only in so far as it is a commodity to that other person. Thus, the same relation appears as a proportion between commodities as magnitudes of the same denomination, but differing qualitatively; or, as an expression of their equivalence as embodiments of universal labor-time, and, at the same time, as a relation of qualitatively different objects, of use-values intended for the satisfaction of