prices; but yet, as all light is the result of conflict, debate,
though it may be a proof of uncertainty, has for its object,
setting aside the greater or less amount of good faith that
enters into it, the discovery of the relation of values to each
other,-- that is, their measurement, their law.

Ricardo, in his theory of rent, has given a magnificent example
of the commensurability of values. He has shown that arable
lands are to each other as the crops which they yield with the
same outlay; and here universal practice is in harmony with
theory. Now who will say that this positive and sure method of
estimating the value of land, and in general of all engaged
capital, cannot be applied to products also? . . . . .

They say: Political economy is not affected by a priori
arguments; it pronounces only upon facts. Now, facts and
experience teach us that there is no measure of value and can be
none, and prove that, though the conception of such an idea was
necessary in the nature of things, its realization is wholly
chimerical. Supply and demand is the sole law of exchange.

I will not repeat that experience proves precisely the contrary;
that everything, in the economic progress of society, denotes a
tendency toward the constitution and establishment of value; that
that is the culminating point of political economy--which by this
constitution becomes transformed--and the supreme indication of
order in society: this general outline, reiterated without proof,
would become tiresome. I confine myself for the moment within
the limits of the discussion, and say that SUPPLY and DEMAND,
held up as the sole regulators of value, are nothing more than