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 particular wants, in short, a relation in which they are distinguished as actual use-values. But this equivalence and non-equivalence mutually exclude each other. Thus
