Summer 1927, D3/12/3: 37 ‒ 40; A4.14.ii ‒ iii
We shall mainly be concerned with the study of the causes of the determination of the price of an individual commodity, considered separately from all the others; we shall assume that all prices and quantities of other commodities are constant (i.e. not affected by variations of our own), and regard them as data of our problem.*
[* We shall also assume that our commodity is only one of a great number that is produced with the same factors of production and consumed by the same consumers, so that its variations cannot appreciably affect marginal utility of money and cost of factors of production.]
We shall therefore take into consideration only demand prices and expenses of production, without regard of the utilities and real costs which may be behind them.*
[* expand according to Marshall 338–9.]
It would not be legitimate, under the given hypotheses, to follow a different course: in fact, the only way of measuring the utilities of our commodity, is to observe the amount of money sacrifice that each successive dose is able to call forth and, being a very specialised commodity, the slope of the demand curve for it will be chiefly determined by the prices of substitutes (at fixed prices) and by their efficiency in giving utility, and only to a negligible extent by its «absolute utility»: and we shall not be able to go behind the prices of substitutes to find out their utility, as, ex hypothesis, we cannot make vary their consumption.*
[* Demand curves are inter-destructive: Wicksteed.]
On the other hand, cost of production would be only the loss of remuneration {of production factors} involved in not using them (at fixed remuneration) in the other industries, which would, ex hypothesi, be willing to take any amount of them at fixed prices.*
[* expand explain why it is necessary to stick very rigidly to the hypotheses.]
But this method of reasoning {about distribution} is legitimate only in respect of one commodity at a time: we could of course apply it in succession to each of the other commodities (so far as they can reasonably be brought within such hypotheses: not, e.g., corn) but not to all or several commodities at the same time.
We can therefore go without a conception of ultimate standard of value: our standard is − the value of other commodities: and this can be done, and is useful so far as we want to inquire into the internal organisation of an industry and its methods of marketing.
But so soon as we want to analyse how the general equilibrium is reached – i.e. we want to analyse the interactions of one commodity upon the other, how they affect each other’s conditions of production and utilities, and how the remuneration of common factors of production is determined − then an ultimate standard of value is required. We can no more refer the costs and utilities of one article to the costs and utilities of another one − in this case this would beg the question, and we would be reasoning in a circle.
Two standards offered: they are the same thing – words. But the intermediate is illegitimate: you cannot say where one begins and the other ends: and they are not independent. And if they were could they be measured one in terms of the other? crossing curves, Bernoulli? or Wicksteed
However there is one reality in cost, i.e. labour.














