MARXIAN POLITICAL ECONOMY 49 5 pens = 1 pair of slippers. If the quantitative aspect (5 against 1) is left out for the moment, it equates pens to slippers. That is to say, this is a qualitative as well as a quantitative equation. There must be something common to the pen and the slippers that makes them commensurable. The qualitative problem is ••'what is this common element in the dissimilar commodities that makes them exchangeable for one another? It cannot be the physical, chemical or other natural proper, ties since what distinguishes the commodities from one another is that they are different use values. To say that it is 'money9 that equates the commodities to each other explains nothing since money, a social arrangement par excellence, is itself a product of the development of commodity production, and thus must have its own origin explained by the prior explanation of the basis of exchange value. If we examine the most diverse commodities carefully, leaving out their character of being use values (since exchange is characterized precisely by abstraction from use on the part of the seller), we find that.? they have one common property: being products of human labour they are the results, so to speak, of the expenditure of various portions of t he total labour expended in society. It is important to note that a ^leap9 in thought has occurred here. In abstracting from the specific characteristics of use values associated with the various commodities we are also thus necessarily adstracting from the specific characteristics of the different kinds of labour that go into these commodities (such as spinning in yarn, weaving in cloth). Thus we can say from a theoretical standpoint that the common element making for qualitative equality (a precondition for commensurability) of different commodities is that they are all products of^human labour in general",without regard to the specific kinds of labour involved. It is this property shared by all commodities, that makes them values. Marx put it thus: ^When looked at as crystals of this social substance [crystals of ^human labour in general, or abstract labour] common to them all, they [commodities] are— values99.4 A commodity may be seen, in the light of the above, as both a value and a use-value, exhange value being merely the phenomenal form of value. What Marx means by the term value, qualitatively, is the specific social property shared by a commodity with all other commodities, namely being the product of ^abstract human labour99. The significance of the terms value and abstract labour needs to be gone into. Before so doing, let us briefly revert to the quantitative aspect of the exchange-value problem. If the value of a commodity, qualitatively speaking.is its property "of being an embodiment or congelation of human labour in the abstract, the quantitative measure of value that suggests itself is the quantity of labour time involved in the production of the commodity, or the magnitude of labour time required to produce it. This needs to be qualified further,