The Medium Of Circulationby Karl Marx
A. The Metamorphosis of Commodities
Chapter 2 showed that the exchange of commodities implies contradictory and mutually exclusive conditions.
The difference between commodities and money does not sweep away these inconsistencies. Instead it develops a modus vivendi, a form in which they can exist side by side.
This is how real contradictions are reconciled.
Exchange is a process that transfers commodities from hands in which they are non-use-values, to hands in which they become use-values. It is a social circulation of matter.
The product of one form of useful labour replaces that of another. When once a commodity has found a resting-place, where it can serve as a use-value, it falls out of the sphere of exchange into that of consumption.
But the former sphere alone interests us at present. We have, therefore, now to consider exchange from a formal point of view; to investigate the change of form or metamorphosis of commodities which effectuates the social circulation of matter.
The comprehension of this change of form is, as a rule, very imperfect. The cause of this imperfection is, apart from indistinct notions of value itself, that every change of form in a commodity results from the exchange of two commodities, an ordinary one and the money-commodity.
If we keep in view the material fact alone that a commodity has been exchanged for gold, we overlook the very thing that we ought to observe — namely, what has happened to the form of the commodity. We overlook the facts that gold, when a mere commodity, is not money, and that when other commodities express their prices in gold, this gold is but the money-form of those commodities themselves.
Commodities, first of all, enter into the process of exchange just as they are. The process then differentiates them into commodities and money, and thus produces an external opposition corresponding to the internal opposition inherent in them, as being at once use-values and values. Commodities as use-values now stand opposed to money as exchange-value. On the other hand, both opposing sides are commodi ties, unities of use-value and value.
But this unity of differences manifests itself at two opposite poles, and at each pole in an opposite way. Being poles they are as necessarily opposite as they are connected. On the one side of the equation we have an ordinary commodity, which is in reality a use-value. Its value is expressed only ideally in its price, by which it is equated to its opponent, the gold, as to the real embodiment of its value. On the other hand, the gold, in its metallic reality, ranks as the embodiment of value, as money.
Gold, as gold, is exchange-value itself. As to its use-value, that has only an ideal existence, represented by the series of expressions of relative value in which it stands face to face with all other commodities, the sum of whose uses makes up the sum of the various uses of gold. These antagonistic forms of commodities are the real forms in which the process of their exchange moves and takes place.
Let us now accompany the owner of some commodity — say, our old friend the weaver of linen — to the scene of action, the market. His 20 yards of linen has a definite price, £2. He exchanges it for the £2, and then, like a man of the good old stamp that he is, he parts with the £2 for a family Bible of the same price.
The linen, which in his eyes is a mere commodity, a depository of value, he alienates in exchange for gold, which is the linen’s value-form, and this form he again parts with for another commodity, the Bible, which is destined to enter his house as an object of utility and of edification to its inmates. The exchange becomes an accomplished fact by two metamorphoses of opposite yet supplementary character — the conversion of the commodity into money, and the re-conversion of the money into a commodity.
The two phases of this metamorphosis are both of them distinct transactions of the weaver — selling, or the exchange of the commodity for money; buying, or the exchange of the money for a commodity; and, the unity of the two acts, selling in order to buy.
The result of the whole transaction, as regards the weaver, is this, that instead of being in possession of the linen, he now has the Bible; instead of his original commodity, he now possesses another of the same value but of different utility. In like manner he procures his other means of subsistence and means of production. From his point of view, the whole process effectuates nothing more than the exchange of the product of his labour for the product of some one else’s, nothing more than an exchange of products.
The exchange of commodities is therefore accompanied by the following changes in their form.
Commodity — Money — Commodity. C——— M ———C.
The result of the whole process is, so far as concerns the objects themselves, C — C, the exchange of one commodity for another, the circulation of materialised social labour. When this result is attained, the process is at an end. C — M. First metamorphosis, or sale
The leap taken by value from the body of the commodity, into the body of the gold, is, as I have elsewhere called it, the salto mortale of the commodity. If it falls short, then, although the commodity itself is not harmed, its owner decidedly is. The social division of labour causes his labour to be as one-sided as his wants are many-sided. This is precisely the reason why the product of his labour serves him solely as exchange-value. But it cannot acquire the properties of a socially recognised universal equivalent, except by being converted into money. That money, however, is in some one else’s pocket.
In order to entice the money out of that pocket, our friend’s commodity must, above all things, be a use-value to the owner of the money. For this, it is necessary that the labour expended upon it, be of a kind that is socially useful, of a kind that constitutes a branch of the social division of labour. But division of labour is a system of production which has grown up spontaneously and continues to grow behind the backs of the producers. The commodity to be exchanged may possibly be the product of some new kind of labour, that pretends to satisfy newly arisen requirements, or even to give rise itself to new requirements.
A particular operation, though yesterday, perhaps, forming one out of the many operations conducted by one producer in creating a given commodity, may to-day separate itself from this connexion, may establish itself as an independent branch of labour and send its incomplete product to market as an independent commodity. The circumstances may or may not be ripe for such a separation.
Today, the product satisfies a social want.
Tomorrow the article may, either altogether or partially, be superseded by some other appropriate product. Moreover, although our weaver’s labour may be a recognised branch of the social division of labour, yet that fact is by no means sufficient to guarantee the utility of his 20 yards of linen. If the community’s want of linen, and such a want has a limit like every other want, should already be saturated by the products of rival weavers, our friend’s product is superfluous, redundant, and consequently useless. Although people do not look a gift-horse in the mouth, our friend does not frequent the market for the purpose of making presents. But suppose his product turn out a real use-value, and thereby attracts money?
The question arises, how much will it attract? No doubt the answer is already anticipated in the price of the article, in the exponent of the magnitude of its value. We leave out of consideration here any accidental miscalculation of value by our friend, a mistake that is soon rectified in the market.
We suppose him to have spent on his product only that amount of labour-time that is on an average socially necessary. The price then, is merely the money-name of the quantity of social labour realised in his commodity. But without the leave, and behind the back, of our weaver, the old-fashioned mode of weaving undergoes a change. The labour-time that yesterday was without doubt socially necessary to the production of a yard of linen, ceases to be so to-day, a fact which the owner of the money is only too eager to prove from the prices quoted by our friend’s competitors.
Unluckily for him, weavers are not few and far between. Lastly, suppose that every piece of linen in the market contains no more labour-time than is socially necessary. In spite of this, all these pieces taken as a whole, may have had superfluous labour-time spent upon them. If the market cannot stomach the whole quantity at the normal price of 2 shillings a yard, this proves that too great a portion of the total labour of the community has been expended in the form of weaving. The effect is the same as if each individual weaver had expended more labour-time upon his particular product than is socially necessary. Here we may say, with the German proverb= caught together, hung together. All the linen in the market counts but as one article of commerce, of which each piece is only an aliquot part. And as a matter of fact, the value also of each single yard is but the materialised form of the same definite and socially fixed quantity of homogeneous human labour. 
We see then, commodities are in love with money, but “the course of true love never did run smooth.” The quantitative division of labour is brought about in exactly the same spontaneous and accidental manner as its qualitative division. The owners of commodities therefore find out, that the same division of labour that turns them into independent private producers, also frees the social process of production and the relations of the individual producers to each other within that process, from all dependence on the will of those producers, and that the seeming mutual independence of the individuals is supplemented by a system of general and mutual dependence through or by means of the products.
The division of labour converts the product of labour into a commodity, and thereby makes necessary its further conversion into money. At the same time it also makes the accomplishment of this transubstantiation quite accidental. Here, however, we are only concerned with the phenomenon in its integrity, and we therefore assume its progress to be normal. Moreover, if the conversion take place at all, that is, if the commodity be not absolutely unsaleable, its metamorphosis does take place although the price realised may be abnormally above or below the value.
The seller has his commodity replaced by gold, the buyer has his gold replaced by a commodity. The fact which here stares us in the face is, that a commodity and gold, 20 yards of linen and £2, have changed hands and places, in other words, that they have been exchanged. But for what is the commodity exchanged? For the shape assumed by its own value, for the universal equivalent. And for what is the gold exchanged?
For a particular form of its own use-value. Why does gold take the form of money face to face with the linen? Because the linen’s price of £2, its denomination in money, has already equated the linen to gold in its character of money. A commodity strips off its original commodity-form on being alienated, i.e., on the instant its use-value actually attracts the gold, that before existed only ideally in its price. The realisation of a commodity’s price, or of its ideal value-form, is therefore at the same time the realisation of the ideal use-value of money; the conversion of a commodity into money, is the simultaneous conversion of money into a commodity. The apparently single process is in reality a double one. From the pole of the commodity-owner it is a sale, from the opposite pole of the money-owner, it is a purchase. In other words, a sale is a purchase, C—M is also M—C. 
Up to this point we have considered men in only one economic capacity, that of owners of commodities, a capacity in which they appropriate the produce of the labour of others, by alienating that of their own labour. Hence, for one commodity-owner to meet with another who has money, it is necessary, either, that the product of the labour of the latter person, the buyer, should be in itself money, should be gold, the material of which money consists, or that his product should already have changed its skin and have stripped off its original form of a useful object. In order that it may play the part of money, gold must of course enter the market at some point or other. This point is to be found at the source of production of the metal, at which place gold is bartered, as the immediate product of labour, for some other product of equal value. From that moment it always represents the realised price of some commodity.
Apart from its exchange for other commodities at the source of its production, gold, in whose-so-ever hands it may be, is the transformed shape of some commodity alienated by its owner; it is the product of a sale or of the first metamorphosis C—M.  Gold, as we saw, became ideal money, or a measure of values, in consequence of all commodities measuring their values by it, and thus contrasting it ideally with their natural shape as useful objects, and making it the shape of their value. It became real money, by the general alienation of commodities, by actually changing places with their natural forms as useful objects, and thus becoming in reality the embodiment of their values. When they assume this money-shape, commodities strip off every trace of their natural use-value, and of the particular kind of labour to which they owe their creation, in order to transform themselves into the uniform, socially recognised incarnation of homogeneous human labour.
We cannot tell from the mere look of a piece of money, for what particular commodity it has been exchanged. Under their money-form all commodities look alike. Hence, money may be dirt, although dirt is not money. We will assume that the two gold pieces, in consideration of which our weaver has parted with his linen, are the metamorphosed shape of a quarter of wheat. The sale of the linen, C—M, is at the same time its purchase, M—C.
But the sale is the first act of a process that ends with a transaction of an opposite nature, namely, the purchase of a Bible; the purchase of the linen, on the other hand, ends a movement that began with a transaction of an opposite nature, namely, with the sale of the wheat. C—M (linen—money), which is the first phase of C—M—C (linen—money—Bible), is also M—C (money—linen), the last phase of another movement C—M—C (wheat—money—linen). The first metamorphosis of one commodity, its transformation from a commodity into money, is therefore also invariably the second metamorphosis of some other commodity, the retransformation of the latter from money into a commodity.
M—C, or purchase.
The second and concluding metamorphosis of a commodity.
Because money is the metamorphosed shape of all other commodities, the result of their general alienation, for this reason it is alienable itself without restriction or condition. It reads all prices backwards, and thus, so to say, depicts itself in the bodies of all other commodities, which offer to it the material for the realisation of its own use-value. At the same time the prices, wooing glances cast at money by commodities, define the limits of its convertibility, by pointing to its quantity.
Since every commodity, on becoming money, disappears as a commodity, it is impossible to tell from the money itself, how it got into the hands of its possessor, or what article has been changed into it. Non olet, from whatever source it may come. Representing on the one hand a sold commodity, it represents on the other a commodity to be bought. 
M—C, a purchase, is, at the same time, C—M, a sale; the concluding metamorphosis of one commodity is the first metamorphosis of another. With regard to our weaver, the life of his commodity ends with the Bible, into which he has reconverted his £2. But suppose the seller of the Bible turns the £2 set free by the weaver into brandy M—C, the concluding phase of C—M—C (linen—money—Bible), is also C—M, the first phase of C—M—C (Bible—money—brandy).
The producer of a particular commodity has that one article alone to offer; this he sells very often in large quantities, but his many and various wants compel him to split up the price realised, the sum of money set free, into numerous purchases. Hence a sale leads to many purchases of various articles. The concluding metamorphosis of a commodity thus constitutes an aggregation of first metamorphoses of various other commodities.
If we now consider the completed metamorphosis of a commodity, as a whole, it appears in the first place, that it is made up of two opposite and complementary movements, C—M and M—C. These two antithetical transmutations of a commodity are brought about by two antithetical social acts on the part of the owner, and these acts in their turn stamp the character of the economic parts played by him. As the person who makes a sale, he is a seller; as the person who makes a purchase, he is a buyer. But just as, upon every such transmutation of a commodity, its two forms, commodity-form and money-form, exist simultaneously but at opposite poles, so every seller has a buyer opposed to him, and every buyer a seller. While one particular commodity is going through its two transmutations in succession, from a commodity into money and from money into another commodity, the owner of the commodity changes in succession his part from that of seller to that of buyer. These characters of seller and buyer are therefore not permanent, but attach themselves in turns to the various persons engaged in the circulation of commodities.
The complete metamorphosis of a commodity, in its simplest form, implies four extremes, and three dramatic personae. First, a commodity comes face to face with money; the latter is the form taken by the value of the former, and exists in all its hard reality, in the pocket of the buyer. A commodity-owner is thus brought into contact with a possessor of money. So soon, now, as the commodity has been changed into money, the money becomes its transient equivalent-form, the use-value of which equivalent-form is to be found in the bodies of other commodities. Money, the final term of the first transmutation, is at the same time the starting-point for the second. The person who is a seller in the first transaction thus becomes a buyer in the second, in which a third commodity-owner appears on the scene as a seller. 
The two phases, each inverse to the other, that make up the metamorphosis of a commodity constitute together a circular movement, a circuit= commodity-form, stripping off of this form, and return to the commodity-form. No doubt, the commodity appears here under two different aspects. At the starting-point it is not a use-value to its owner; at the finishing point it is. So, too, the money appears in the first phase as a solid crystal of value, a crystal into which the commodity eagerly solidifies, and in the second, dissolves into the mere transient equivalent-form destined to be replaced by a use-value.
The two metamorphoses constituting the circuit are at the same time two inverse partial metamorphoses of two other commodities. One and the same commodity, the linen, opens the series of its own metamorphoses, and completes the metamorphosis of another (the wheat). In the first phase or sale, the linen plays these two parts in its own person. But, then, changed into gold, it completes its own second and final metamorphosis, and helps at the same time to accomplish the first metamorphosis of a third commodity. Hence the circuit made by one commodity in the course of its metamorphoses is inextricably mixed up with the circuits of other commodities. The total of all the different circuits constitutes the circulation of commodities.
The circulation of commodities differs from the direct exchange of products (barter), not only in form, but in substance. Only consider the course of events. The weaver has, as a matter of fact, exchanged his linen for a Bible, his own commodity for that of some one else. But this is true only so far as he himself is concerned. The seller of the Bible, who prefers something to warm his inside, no more thought of exchanging his Bible for linen than our weaver knew that wheat had been exchanged for his linen. B’s commodity replaces that of A, but A and B do not mutually exchange those commodities.
It may, of course, happen that A and B make simultaneous purchases, the one from the other; but such exceptional transactions are by no means the necessary result of the general conditions of the circulation of commodities. We see here, on the one hand, how the exchange of commodities breaks through all local and personal bounds inseparable from direct barter, and develops the circulation of the products of social labour; and on the other hand, how it develops a whole network of social relations spontaneous in their growth and entirely beyond the control of the actors. It is only because the farmer has sold his wheat that the weaver is enabled to sell his linen, only because the weaver has sold his linen that our Hotspur is enabled to sell his Bible, and only because the latter has sold the water of everlasting life that the distiller is enabled to sell his eau-de-vie, and so on.
The process of circulation, therefore, does not, like direct barter of products, become extinguished upon the use-values changing places and hands. The money does not vanish on dropping out of the circuit of the metamorphosis of a given commodity. It is constantly being precipitated into new places in the arena of circulation vacated by other commodities. In the complete metamorphosis of the linen, for example, linen — money — Bible, the linen first falls out of circulation, and money steps into its place. Then the Bible falls out of circulation, and again money takes its place. When one commodity replaces another, the money-commodity always sticks to the hands of some third person.  Circulation sweats money from every pore.
Nothing can be more childish than the dogma, that because every sale is a purchase, and every purchase a sale, therefore the circulation of commodities necessarily implies an equilibrium of sales and purchases. If this means that the number of actual sales is equal to the number of purchases, it is mere tautology. But its real purport is to prove that every seller brings his buyer to market with him. Nothing of the kind.
The sale and the purchase constitute one identical act, an exchange between a commodity-owner and an owner of money, between two persons as opposed to each other as the two poles of a magnet. They form two distinct acts, of polar and opposite characters, when performed by one single person. Hence the identity of sale and purchase implies that the commodity is useless, if, on being thrown into the alchemistical retort of circulation, it does not come out again in the shape of money; if, in other words, it cannot be sold by its owner, and therefore be bought by the owner of the money. That identity further implies that the exchange, if it does take place, constitutes a period of rest, an interval, long or short, in the life of the commodity. Since the first metamorphosis of a commodity is at once a sale and a purchase, it is also an independent process in itself. The purchaser has the commodity, the seller has the money, i.e., a commodity ready to go into circulation at any time. No one can sell unless some one else purchases.
But no one is forthwith bound to purchase, because he has just sold. Circulation bursts through all restrictions as to time, place, and individuals, imposed by direct barter, and this it effects by splitting up, into the antithesis of a sale and a purchase, the direct identity that in barter does exist between the alienation of one’s own and the acquisition of some other man’s product. To say that these two independent and antithetical acts have an intrinsic unity, are essentially one, is the same as to say that this intrinsic oneness expresses itself in an external antithesis. If the interval in time between the two complementary phases of the complete metamorphosis of a commodity become too great, if the split between the sale and the purchase become too pronounced, the intimate connexion between them, their oneness, asserts itself by producing — a crisis.
The antithesis, use-value and value; the contradictions that private labour is bound to manifest itself as direct social labour, that a particularised concrete kind of labour has to pass for abstract human labour; the contradiction between the personification of objects and the representation of persons by things; all these antitheses and contradictions, which are immanent in commodities, assert themselves, and develop their modes of motion, in the antithetical phases of the metamorphosis of a commodity. These modes therefore imply the possibility, and no more than the possibility, of crises. The conversion of this mere possibility into a reality is the result of a long series of relations, that, from our present standpoint of simple circulation, have as yet no existence.