The Letter, Issue 15, Spring 1999, Pages 84 - 89
EXCHANGE-VALUE AND USE IN PSYCHOANALYSIS
One of the topics dealt with in the seminar on the Logic of Phantasy concerns the question as to whether or not, at the level of the unconscious, we are structured as male or female subjects. In order to tease out this idea Lacan initially refers to Marx's discussion on the value and its subsystem of use-value and exchange-value.
In order to give an understanding of Marx, I believe it best to let him speak for himself, for it is not possible for me to gild that lily.
Use-value derives from the material properties of a commodity, such as the ability of a watch to tell the time, or a car to get us to our destination.
Exchange-value is related to use-value in a quantitative relation and represents the proportion in which the use- value of one commodity is exchanged for the use-value of another commodity. This relation changes constantly with time and place and appears to be something accidental and purely relative, and consequently an intrinsic value, that is, an exchange value that is inseperably connected with the commodity, inherent in it, seems a contradiction in terms. If, for example, a kilo of wheat is exchanged for x boot-polish, y silk or z gold etc., this is in effect done so in the most diverse proportions. Therefore, the wheat has many exchange values instead of one. But x boot-polish, y silk or z gold, must be mutually replaceable or of identical magnitude. It follows from this that valid exchange-values of a particular commodity express something equal, and secondly, exchange-values cannot be anything other than the mode of expression, the form of appearance of a content
distinguishable from it. Let us now take two commodities, for example corn and iron. Whatever their exchange values may be, it can always be represented by an equation in which a given quantity of com is equated to some quantity of iron, for instance one kilo of corn = x kilos of iron. What does this equation signify? It signifies that a common element of identical magnitude exists in two different things, in 1 kilo of corn and similarly in x kilos of iron. Both are therefore equal to a third thing, which in itself is neither one nor the other. Each of them, so far as its exchange-value must be reducible to this third thing.