Chapter VIII

, §10]

But this somewhat tame conclusion does not make it any less important to grasp clearly the significance of the appreciation in the value of capital goods. A failure to realize it lies at the root of our bewildered muddling of many crucial problems of the day. In the matter of housing, for instance, we know we cannot build houses at less than two or three times their prewar cost, and yet we cannot endure to see the owners of pre-war houses obtaining a commensurate increase of rent. And so, in Great Britain, we pass Rent Restriction Acts, and Housing Acts, and then, in a fit of economy we suspend the latter, and let the former stand, while the housing shortage becomes steadily more acute. When we hand the railways back from State control to private hands, our horror at the idea of the companies receiving larger money profits than they did before the war leads us to lay down principles for the fixing of fares and freight charges, which take no account of post-war construction costs; and then, in alarm lest we may have thereby made it unprofitable for the companies to spend a single penny of fresh capital upon further development, we seek to provide for capital expenditure by cumbrous and dubious expedients. Doubtless we shall muddle through somehow with such policies: and, public opinion being what it is, they may perhaps have been about the best policies that were practicable. But the problems would have been easier to handle, if the public generally were a little less disposed to think in terms of averages, and a little more in terms of margins, if we all of us instinctively realized that the cost that really matters is the cost at which additional production is profitable under the conditions ruling at the time, or in the immediate future.

§6. _General Relation between Price, Utility and Cost_. Let us conclude this chapter by summing up the conclusions which have emerged as to the relations of utility and cost to price.

The price of a commodity is determined by the conditions of both supply and demand; and neither can logically be said to be the superior influence, though it may sometimes be convenient to concentrate our attention on one or other of them. The chief factor on which the conditions of demand depend is the utility (as measured in terms of money). The chief factor on which the conditions of supply depend is the cost of production (again as measured in terms of money). The prevailing trend towards an equilibrium of demand and supply can thus be expressed as follows:--

LAW VI. A commodity tends to be produced on a scale at which its marginal cost of production is equal to its marginal utility, as measured in terms of money, and both are equal to its price.

##