1 56 
ON METHODS OF 
position that all commodities were doubled in 
quantity, this is the result, in whichever of the 
commodities or parts we choose to estimate the 
whole. But if any one commodity is supposed 
to be produced in the same quantity by the 
same labour as before, and the whole of the 
other commodities are estimated in this one, it 
will be true enough, that the whole produce 
continues of the same value, while the parts 
have fallen one half*. From this it is evident, 
that in all such cases the result depends on the 
commodity chosen as the medium of estima- 
tion. As by value we always imply value in 
something, a commodity may be said by one 
person to rise, and by another to fall, and with 
equal truth, if they speak with tacit reference 
to different commodities; but a general affirma- 
tion of this nature is worse than useless. The 
assertion of a rise or fall in any thing should 
be accompanied by a mention of the commo- 
* Assuming that commodities are to each other in value 
as the quantities of labour concerned in their production.