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linen, but a definite quantity of coat (1 coat) is made the equivalent of a definite quantity (20
yards) of linen.
The equation, 20 yards of linen = 1 coat, or 20 yards of linen are worth one coat, implies that the
same quantity of value substance (congealed labour) is embodied in both; that the two
commodities have each cost the same amount of labour of the same quantity of labour time. But
the labour time necessary for the production of 20 yards of linen or 1 coat varies with every
change in the productiveness of weaving or tailoring. We have now to consider the influence of
such changes on the quantitative aspect of the relative expression of value.
I. Let the value of the linen vary,
20
that of the coat remaining constant. If, say in consequence
of the exhaustion of flax-growing soil, the labour time necessary for the production of the linen
be doubled, the value of the linen will also be doubled. Instead of the equation, 20 yards of linen
= 1 coat, we should have 20 yards of linen = 2 coats, since 1 coat would now contain only half the
labour time embodied in 20 yards of linen. If, on the other hand, in consequence, say, of
improved looms, this labour time be reduced by one-half, the value of the linen would fall by
one-half. Consequently, we should have 20 yards of linen = ½ coat. The relative value of
commodity A, i.e., its value expressed in commodity B, rises and falls directly as the value of A,
the value of B being supposed constant.
II. Let the value of the linen remain constant, while the value of the coat varies. If, under
these circumstances, in consequence, for instance, of a poor crop of wool, the labour time
necessary for the production of a coat becomes doubled, we have instead of 20 yards of linen = 1
coat, 20 yards of linen = ½ coat. If, on the other hand, the value of the coat sinks by one-half, then
20 yards of linen = 2 coats. Hence, if the value of commodity A remain constant, its relative value
expressed in commodity B rises and falls inversely as the value of B.
If we compare the different cases in I and II, we see that the same change of magnitude in relative
value may arise from totally opposite causes. Thus, the equation, 20 yards of linen = 1 coat,
becomes 20 yards of linen = 2 coats, either, because the value of the linen has doubled, or
because the value of the coat has fallen by one-half; and it becomes 20 yards of linen = ½ coat,
either, because the value of the linen has fallen by one-half, or because the value of the coat has
doubled.
III. Let the quantities of labour time respectively necessary for the production of the linen and
the coat vary simultaneously in the same direction and in the same proportion. In this case 20
yards of linen continue equal to 1 coat, however much their values may have altered. Their
change of value is seen as soon as they are compared with a third commodity, whose value has
remained constant. If the values of all commodities rose or fell simultaneously, and in the same
proportion, their relative values would remain unaltered. Their real change of value would appear
from the diminished or increased quantity of commodities produced in a given time.
IV. The labour time respectively necessary for the production of the linen and the coat, and
therefore the value of these commodities may simultaneously vary in the same direction, but at
unequal rates or in opposite directions, or in other ways. The effect of all these possible different
variations, on the relative value of a commodity, may be deduced from the results of I, II, and III.
Thus real changes in the magnitude of value are neither unequivocally nor exhaustively reflected
in their relative expression, that is, in the equation expressing the magnitude of relative value. The
relative value of a commodity may vary, although its value remains constant. Its relative value
may remain constant, although its value varies; and finally, simultaneous variations in the
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Chapter 1
magnitude of value and in that of its relative expression by no means necessarily correspond in
amount.
21
3. The Equivalent form of value
We have seen that commodity A (the linen), by expressing its value in the use value of a
commodity differing in kind (the coat), at the same time impresses upon the latter a specific form
of value, namely that of the equivalent. The commodity linen manifests its quality of having a
value by the fact that the coat, without having assumed a value form different from its bodily
form, is equated to the linen. The fact that the latter therefore has a value is expressed by saying
that the coat is directly exchangeable with it. Therefore, when we say that a commodity is in the
equivalent form, we express the fact that it is directly exchangeable with other commodities.
When one commodity, such as a coat, serves as the equivalent of another, such as linen, and coats
consequently acquire the characteristic property of being directly exchangeable with linen, we are
far from knowing in what proportion the two are exchangeable. The value of the linen being
given in magnitude, that proportion depends on the value of the coat. Whether the coat serves as
the equivalent and the linen as relative value, or the linen as the equivalent and the coat as relative
value, the magnitude of the coat’s value is determined, independently of its value form, by the
labour time necessary for its production. But whenever the coat assumes in the equation of value,
the position of equivalent, its value acquires no quantitative expression; on the contrary, the
commodity coat now figures only as a definite quantity of some article.
For instance, 40 yards of linen are worth – what? 2 coats. Because the commodity coat here plays
the part of equivalent, because the use-value coat, as opposed to the linen, figures as an
embodiment of value, therefore a definite number of coats suffices to express the definite quantity
of value in the linen. Two coats may therefore express the quantity of value of 40 yards of linen,
but they can never express the quantity of their own value. A superficial observation of this fact,
namely, that in the equation of value, the equivalent figures exclusively as a simple quantity of
some article, of some use value, has misled Bailey, as also many others, both before and after
him, into seeing, in the expression of value, merely a quantitative relation. The truth being, that
when a commodity acts as equivalent, no quantitative determination of its value is expressed.
The first peculiarity that strikes us, in considering the form of the equivalent, is this: use value
becomes the form of manifestation, the phenomenal form of its opposite, value.
The bodily form of the commodity becomes its value form. But, mark well, that this quid pro quo
exists in the case of any commodity B, only when some other commodity A enters into a value
relation with it, and then only within the limits of this relation. Since no commodity can stand in
the relation of equivalent to itself, and thus turn its own bodily shape into the expression of its
own value, every commodity is compelled to choose some other commodity for its equivalent,
and to accept the use value, that is to say, the bodily shape of that other commodity as the form of
its own value.
One of the measures that we apply to commodities as material substances, as use values, will
serve to illustrate this point. A sugar-loaf being a body, is heavy, and therefore has weight: but we
can neither see nor touch this weight. We then take various pieces of iron, whose weight has been
determined beforehand. The iron, as iron, is no more the form of manifestation of weight, than is
the sugar-loaf. Nevertheless, in order to express the sugar-loaf as so much weight, we put it into a
weight-relation with the iron. In this relation, the iron officiates as a body representing nothing
but weight. A certain quantity of iron therefore serves as the measure of the weight of the sugar,
and represents, in relation to the sugar-loaf, weight embodied, the form of manifestation of
weight. This part is played by the iron only within this relation, into which the sugar or any other