AT DIFFERENT PERIODS. 83

position, that when one commodity or thing al-
ters its value in relation to other commodities,
the mutual relations of these other commodi-
ties, ceteris paribus, are not thereby affected *.

The reader will notice, that in supposing that
while the value of the producing labour was
doubled, the commodity remained the same, I
have used the expression, the value of the
commodity might not be affected,” for this rea-
son, that whether it was or was not affected,
would depend on the nature of the cause by
which the value of the labour was doubled.
In the proposition, the values of A and B are to
each other as the values of their producing la-
bour, the value of labour means aggregate
value. Now the aggregate value of the labour
necessary for the production of a commodity
may be increased in two ways, either by an
augmentation of the quantity of the labour at

* It may be necessary perhaps to state, that by the qua-
lification ceteris paribus, it is meant to restrict the propo-
sition to cases in which the altered commodity either does
not enter at all into the composition of other commodities,
or enters into them in the same proportion.