This common “something” cannot be either a geometrical, a chemical, or any other natural property of commodities. Such properties claim our attention only in so far as they affect the utility of those commodities, make them use values. But the exchange of commodities is evidently an act characterised by a total abstraction from use value. Then one use value is just as good as another, provided only it be present in sufficient quantity. Or, as old Barbon says,

“one sort of wares are as good as another, if the values be equal. There is no difference or distinction in things of equal value ... An hundred pounds’ worth of lead or iron, is of as great value as one hundred pounds’ worth of silver or gold.”

As use values, commodities are, above all, of different qualities, but as exchange values they are merely different quantities, and consequently do not contain an atom of use value.