of social economic value in terms of a feeling-magnitude which an individual can appreciate is not to be had. Value can be measured and quantitatively handled only in terms of _price_. In saying this, I do not mean to impeach that more abstract procedure which speaks of abstract units of value, and uses arithmetical numbers which designate no particular commodities, or algebraic symbols, or even ordinary speech, to indicate quantitative relations among different sums of these abstract units. Such procedure is thoroughly correct, and often highly convenient, if one be dealing with highly general laws, or if one wish to avoid any complications from changes in the value of any concrete commodity which might be chosen as the standard of value. Only, I would insist, such procedure is simply an abstraction from the price concept, and so presupposes it. A unit of value, in the concrete, must be the value of some particular concrete good, which is chosen as the standard. _What_ good is chosen is a purely arbitrary matter, determined by convenience. Abstract value, apart from valuable things, is an utter impossibility--only a Platonic idealism or mediaeval realism could hold the contrary view. And, in order to show how many units of value there are in a good, we must compare it with another good, whose value is the unit, unless, indeed, we arbitrarily choose as our unit the good in question, and say that its value is one unit, or several units, in case we arbitrarily define the unit as a fraction of its value. But clearly this latter procedure would tell us nothing after all as to the amount of the value in the good. It would be a purely formal process--like renaming a "hocus-pocus" and calling it two "Abracadabras." Any real measuring--and real measuring is essential for any quantitative manipulation--implies _two_ things, one of which shall serve as the measure of the other. The conception of abstract _units_ of value, therefore, is an abstraction from the price conception, and presupposes it.[208]