III. Tc ... P (C')

If we combine all three forms, all premises of the process appear as its result, as a premise produced by it itself. Every element appears as a point of departure, of transit, and of return. The total process presents itself as the unity of the processes of production and circulation. The process of production becomes the mediator of the process of circulation and vice versa.

All three circuits have the following in common: The self-expansion of value as the determining purpose, as the compelling motive. In I this is expressed in its form. Formula II begins with P, the very process of creating surplus-value. In III the circuit begins with the self-expanded value, even if the movement is repeated on the same scale.

As C — M means M — C for the buyer, and M — C means C — M for the seller, the circulation of capital presents only the ordinary metamorphosis of commodities, and the laws evolved with regard to it on the mass of money in circulation are valid here. However, if we do not cling to this formal aspect but rather consider the actual connection between the metamorphoses of the various individual capitals, in other words, if we study the connection between the circuits of individual capitals as partial movements of the process of reproduction of the total social capital, then the mere change of form of money and commodities cannot explain the connection.

In a constantly revolving circle every point is simultaneously a point of departure and a point of return. If we interrupt the rotation, not every point of departure is a point of return. Thus we have seen that not only does every individual circuit presuppose (implicite) the others, but also that the repetition of the circuit in one form comprises the performance of the circuit in the other forms. The entire difference thus appears to be a merely formal one, or as a merely subjective distinction existing solely for the observer.

Since every one of these circuits is considered a special form of this movement in which various individual industrial capitals are engaged, this difference exists only as an individual one. But in reality every individual industrial capital is present simultaneously in all three circuits. These three circuits, the forms of reproduction assumed by the three forms of capital, are made continuously side by side. For instance, one part of the capital-value, which now performs the function of commodity-capital, is transformed into money-capital, but at the same time another part leaves the process of production and enters the circulation as a new commodity-capital. The circuit form C' ... C' is thus continuously described; and so are the other two forms. The reproduction of capital in each one of its forms and stages is just as continuous as the metamorphosis of these forms and the successive passage through the three stages. The entire circuit is thus a unity of its three forms.