"To solve this contradiction we must discover its ground. The state takes possession of the remainder, not in respect to its form, as remainder and as property, but in respect to its substance, as something which is necessary to sustain life. In order to solve the contradiction thoroughly, form and substance must, therefore, be separated. The state must have the power of taking the substance without touching the form. Without exhibiting here unnecessary profundity, I shall solve the problem at once. We must discover a mere form of property, a mere sign of it, which is a sign of whatever is useful in the state, without having in itself the least use ; for if it were useful in itself, the state would possess the right to claim it, like the other products, for public purposes. Such a mere form of property is called money. The use of money must be introduced in a state necessarily; and this solves our problem. The producer has not the right to keep his products; he must sell them. Nevertheless, they are his absolute property, guaranteed to him by the state. True, he is not to give them away for nothing, but in exchange for wares. But he needs no wares at present, at least not those which are offered to him. Hence, he receives money. The same applies to the artist. The state is obliged to furnish to the producer wares for his products, and to the artist products for his wares."