# Principles of Political Economy (J.S. Mill, 1871), vol. 1/Book III, Chapter VI

CHAPTER VI.
SUMMARY OF THE THEORY OF VALUE.
§ 1.We have now attained a favourable point for looking back, and taking a simultaneous view of the space which we have traversed since the commencement of the present Book. The following are the principles of the theory of Value, so far as we have yet ascertained them.
I. Value is a relative term. The value of a thing means the quantity of some other thing, or of things in general, which it exchanges for. The values of all things can never, therefore, rise or fall simultaneously. There is no such thing as a general rise or a general fall of values. Every rise of value supposes a fall, and every fall a rise.
II. The temporary or market value of a thing, depends on the demand and supply; rising as the demand rises, and falling as the supply rises. The demand, however, varies with the value, being generally greater when the thing is cheap than when it is dear; and the value always adjusts itself in such a manner, that the demand is equal to the supply.
III. Besides their temporary value, things have also a permanent, or as it may be called, a Natural Value, to which the market value, after every variation, always tends to return; and the oscillations compensate for one another, so that, on the average, commodities exchange at about their natural value.
IV. The natural value of some things is a scarcity value; but most things naturally exchange for one another in the ratio of their cost of production, or at what may be termed their Cost Value.
V. The things which are naturally and permanently at a ​scarcity value, are those of which the supply cannot be increased at all, or not sufficiently to satisfy the whole of the demand which would exist for them at their cost value.
VI. A monopoly value means a scarcity value. Monopoly cannot give a value to anything except through a limitation of the supply.
VII. Every commodity of which the supply can be indefinitely increased by labour and capital, exchanges for other things proportionally to the cost necessary for producing and bringing to market the most costly portion of the supply required. The natural value is synonymous with the Cost Value, and the cost value of a thing, means the cost value of the most costly portion of it.
VIII. Cost of Production consists of several elements, some of which are constant and universal, others occasional. The universal elements of cost of production are, the wages of the labour, and the profits of the capital. The occasional elements are taxes, and any extra cost occasioned by a scarcity value of some of the requisites.
IX. Rent is not an element in the cost of production of the commodity which yields it; except in the cases (rather conceivable than actually existing) in which it results from, and represents, a scarcity value. But when land capable of yielding rent in agriculture is applied to some other purpose, the rent which it would have yielded is an element in the cost of production of the commodity which it is employed to produce.
X. Omitting the occasional elements; things which admit of indefinite increase, naturally and permanently exchange for each other according to the comparative amount of wages which must be paid for producing them, and the comparative amount of profits which must be obtained by the capitalists who pay those wages.
XI. The comparative amount of wages does not depend on what wages are in themselves. High wages do not make high values, nor low wages low values. The comparative ​amount of wages depends partly on the comparative quantities of labour required, and partly on the comparative rates of its remuneration.
XII. So, the comparative rate of profits does not depend on what profits are in themselves; nor do high or low profits make high or low values. It depends partly on the comparative lengths of time during which the capital is employed, and partly on the comparative rate of profits in different employments.
XIII. If two things are made by the same quantity of labour, and that labour paid at the same rate, and if the wages of the labourer have to be advanced for the same space of time, and the nature of the employment does not require that there be a permanent difference in their rate of profit; then, whether wages and profits be high or low, and whether the quantity of labour expended be much or little, these two things will, on the average, exchange for one another.
XIV. If one of two things commands, on the average, a greater value than the other, the cause must be that it requires for its production either a greater quantity of labour, or a kind of labour permanently paid at a higher rate; or that the capital, or part of the capital, which supports that labour, must be advanced for a longer period; or lastly, that the production is attended with some circumstance which requires to be compensated by a permanently higher rate of profit.
XV. Of these elements, the quantity of labour required for the production is the most important: the effect of the others is smaller, though none of them are insignificant.
XVI. The lower profits are, the less important become the minor elements of cost of production, and the less do commodities deviate from a value proportioned to the quantity and quality of the labour required for their production.
XVII. But every fall of profits lowers, in some degree, the cost value of things made with much or durable ​machinery, and raises that of things made by hand; and every rise of profits does the reverse.
§ 2.Such is the general theory of Exchange Value. It is necessary, however, to remark that this theory contemplates a system of production carried on by capitalists for profit, and not by labourers for subsistence. In proportion as we admit this last supposition—and in most countries we must admit it, at least in respect of agricultural produce, to a very great extent such of the preceding theorems as relate to the dependence of value on cost of production will require modification. Those theorems are all grounded on the supposition, that the producer's object and aim is to derive a profit from his capital. This granted, it follows that he must sell his commodity at the price which will afford the ordinary rate of profit, that is to say, it must exchange for other commodities at its cost value. But the peasant proprietor, the metayer, and even the peasant-farmer or allotment-holder—the labourer, under whatever name, producing on his own account—is seeking, not an investment for his little capital, but an advantageous employment for his time and labour. His disbursements, beyond his own maintenance and that of his family, are so small, that nearly the whole proceeds of the sale of the produce are wages of labour. When he and his family have been fed from the produce of the farm (and perhaps clothed with materials grown thereon, and manufactured in the family) he may, in respect of the supplementary remuneration derived from the sale of the surplus produce, be compared to those labourers who, deriving their subsistence from an independent source, can afford to sell their labour at any price which is to their minds worth the exertion. A peasant, who supports himself and his family with one portion of his produce, will often sell the remainder very much below what would be its cost value to the capitalist.
There is, however, even in this case, a minimum, or ​inferior limit, of value. The produce which he carries to market, must bring in to him the value of all necessaries which he is compelled to purchase; and it must enable him to pay his rent. Rent, under peasant cultivation, is not governed by the principles set forth in the chapters immediately preceding, but is either determined by custom, as in the case of metayers, or, if fixed by competition, depends on the ratio of population to land. Rent, therefore, in this case, is an element of cost of production. The peasant must work until he has cleared his rent and the price of all purchased necessaries. After this, he will go on working only if he can sell the produce for such a price as will overcome his aversion to labour.
The minimum just mentioned is what the peasant must obtain in exchange for the whole of his surplus produce. But inasmuch as this surplus is not a fixed quantity, but may be either greater or less according to the degree of his industry, a minimum value for the whole of it does not give any minimum value for a definite quantity of the commodity. In this state of things, therefore, it can hardly be said, that the value depends at all on cost of production. It depends entirely on demand and supply, that is, on the proportion between the quantity of surplus food which the peasants choose to produce, and the numbers of the non-agricultural, or rather of the non-peasant population. If the buying class were numerous and the growing class lazy, food might be permanently at a scarcity price. I am not aware that this case has anywhere a real existence. If the growing class is energetic and industrious, and the buyers few, food will be extremely cheap. This also is a rare case, though some parts of France perhaps approximate to it. The common cases are, either that, as in Ireland until lately, the peasant class is indolent and the buyers few, or the peasants industrious and the town population numerous and opulent, as in Belgium, the north of Italy, and parts of Germany. The price of the produce will adjust itself to these varieties of circumstances, ​unless modified, as in many cases it is, by the competition of producers who are not peasants, or by the prices of foreign markets.
§ 3.Another anomalous case is that of slave-grown produce: which presents, however, by no means the same degree of complication. The slave-owner is a capitalist, and his inducement to production consists in a profit on his capital. This profit must amount to the ordinary rate. In respect to his expenses, he is in the same position as if his slaves were free labourers working with their present efficiency, and were hired with wages equal to their present cost. If the cost is less in proportion to the work done, than the wages of free labour would be, so much the greater are his profits: but if all other producers in the country possess the same advantage, the values of commodities will not be at all affected by it. The only case in which they can be affected, is when the privilege of cheap labour is confined to particular branches of production, free labourers at proportionally higher wages being employed in the remainder. In this case, as in all cases of permanent inequality between the wages of different employments, prices and values receive the impress of the inequality. Slave-grown will exchange for non-slave-grown commodities in a less ratio than that of the quantity of labour required for their production; the value of the former will be less, of the latter greater, than if slavery did not exist.
The further adaptation of the theory of value to the varieties of existing or possible industrial systems may be left with great advantage to the intelligent reader. It is well said by Montesquieu, "II ne faut pas toujours tellement épuiser un sujet, qu'on ne laisse rien à faire au lecteur. Il ne's'agit pas de faire lire, mais de faire penser."