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ON THE NATURE

verting to this, Mr. Ricardo appears to have
reasoned, that because the quantity of labour
{according to his doctrine) is the cause of
value, if the cause in any one commodity remains
 the same, the effect must necessarily be
the same. But granting his doctrine, that the
quantity of labour determines value, it must
be the quantity requisite for the production of
each commodity compared, and not the quantity
 requisite for that of only one. The value
of both, or their relation to each other, must
necessarily vary with every change in the quantity
 of producing labour required for either.
To assert indeed, that the value of an object,
or its relation to another object, was invariable,
because whatever alteration had taken place in
the latter object, the former had undergone no
change in the conditions of its production,
would be as absurd as to assert the unvarying
likeness of a portrait to the original, because,
however the man had altered in feature, the
portrait itself had retained precisely the same
lineaments. The relation of value, as well as