92 ON COMPARING COMMODITIES

In this chapter I beg not to be understood as
contending, either that the values of commodi-
ties are to each other as the quantities of labour
necessary for their production, or that the
values of commodities are to each other as the
values of the labour: all that I intend to insist
upon is, that if the former is true, the latter
cannot be false ; and I have endeavoured to ex-
plain the source of the misconception which
has regarded the two propositions as incompa-
tible and contradictory *. The fact is, that the
quantity of labour and the value of labour are in
the same case. Any alteration in the compara-
tive quantities of labour required to produce a
and B, would alter their value in relation to
gach other; and an alteration in their mutual
value would equally follow from any change in
the comparative values of the producing labour,

* Of the two propositions, however, the latter is a much
nearer approximation to the truth, for reasons which will
be stated in a subsequent chapter on the causes of value.