In a society of producers of commodities, the exchange of commodities is carried out according to the labour socially necessary for their production. Labour is the source and the measure of their exchange-value. Nothing could seem more "just" than this to any man imbued with the ideas engendered by a society of producers of commodities. Unfortunately this "justice" is no more "eternal" than anything else here below. The development of the production of commodities necessarily brings in its train the transformation of the greater part of society into proletarians, possessing nothing but their labour-power, and of the other part into capitalists, who, buying this power, the only commodity of the proletarians, turn it into a source of wealth for themselves. In working for the capitalists the proletarian produces the income of his exploiter, at the same time as his own poverty, his own social subjection. Is not this sufficiently unjust? The partisan of the rights of the producer of commodities deplores the lot of the proletarians; he thunders against capital. But at the same time he thunders against the revolutionary tendencies of the proletarians who speak of expropriating the exploiter and of a communistic organisation of production. Communism is unjust, it is the most odious tyranny. What wants organising is not _production_ but _exchange_, he assures us. But how organise exchange? That is easy enough, and what is daily going on before our eyes may serve to show us the way. Labour is the source and the measure of the _value_ of commodities. But is the _price_ of commodities always determined by their value? Do not prices continually vary according to the rarity or abundance of these commodities? The value of a commodity and its price are two different things; and this is the misfortune, the great misfortune of all of us poor, honest folk, who only want justice, and only ask for our own. To solve the social question, therefore we must put a stop to the _arbitrariness of prices_, and to the anomaly of value (Proudhon's own expressions). And in order to do this we must "constitute" value; _i.e._, see that every producer shall always, in exchange for his commodity, receive exactly what it costs. Then will private property not only cease to be theft, it will become the most adequate expression of justice. To constitute value is to constitute small private property, and small private property once constituted, everything will be justice and happiness in a world now so full of misery and injustice. And it is no good for proletarians to object, they have no means of production: by guaranteeing themselves _credit gratis_, all who want to work will, as by the touch of a magic wand, have everything necessary for production.