Every part describes continuously its own cycle, but it is always another part of capital which exists in this form, and these special cycles form only simultaneous and successive elements of the aggregate process.
The continuity -- instead of the above-described interruption -- of the aggregate process is achieved only in the unity of the three circuits. The aggregate social capital always has this continuity and its process always exhibits the unity of the three circuits.
The continuity of the reproduction is at times more or less interrupted so far as individual capitals are concerned. In the first place the masses of value are frequently distributed at various periods in unequal portions over the various stages and functional forms. In the second place these portions may be differently distributed, according to the character of the commodity to be produced, hence according to the particular sphere of production in which the capital is invested. In the third place the continuity may be more or less broken in those branches of production which are dependent on the seasons, either on account of natural conditions (agriculture, herring catch, etc.) or on account of conventional circumstances, as for instance in so-called seasonal work. The process goes on most regularly and uniformly in the factories and mines. But this difference in the various branches of production does not cause any difference in the general forms of the circular process.
Capital as self-expanding value embraces not only class relations, a society of a definite character resting on the existence of labour in the form of wage-labour. It is a movement, a circuit-describing process going through various stages, which itself comprises three different forms of circuit-describing process. Therefore it can be understood only as a motion, not as a thing at rest. Those who regard the gaining by value of independent existence as a mere abstraction forget that the movement of industrial capital is this abstraction in actu . Value here passes through various forms, various movements in which it maintains itself and at the same time expands, augments. As we are here concerned primarily with the mere form of this movement, we shall not take into consideration the revolutions which capital-value may undergo during its circuit. But it is clear that in spite of all the revolutions of value, capitalist production exists and can endure only so long as capital-value is made to create surplus-value, that is, so long as it describes its circuit as a value that has gained independence, so long therefore as the revolutions in value are overcome and equilibrated in some way. The movements of capital appear as the action of some individual industrial capitalist who performs the functions of a buyer of commodities and labour, a seller of commodities, and an owner of productive capital, who therefore promotes the circuit by this activity.
If social capital experiences a revolution in value, it may happen that the capital of the individual capitalist succumbs to it and fails, because it cannot adapt itself to the conditions of this movement of values. The more acute and frequent such revolutions in value become, the more does the automatic movement of the now independent value operate with the elemental force of a natural process, against the foresight and calculation of the individual capitalist, the more does the course of normal production become subservient to abnormal speculation, and the greater is the danger that threatens the existence of the individual capitals. These periodical revolutions in value therefore corroborate what they are supposed to refute, namely, that value as capital acquires independent existence, which it maintains and accentuates through its movement.
This succession of the metamorphoses of capital in process includes continuous comparison of the change in the magnitude of value of the capital brought about in the circuit with the original value. If value's acquisition of independence of the value-creating power , labour-power, is inaugurated by the act M---L (purchase of labour-power) and is effected during the process of production as exploitation of labour-power , this acquisition of independence on the part of value does not re-appear in that circuit, in which money, commodities, and elements of production are merely alternating forms of capital-value in process, and the former magnitude of value is compared with capital's present changed magnitude of value.
"Value," argues Bailey against the acquisition of independence by value, an independence which is characteristic of the capitalist mode of production and which he treats as an illusion of certain economists;"value is a relation between contemporary commodities, because such only admit of being exchanged for each other." [See Bailey, Samuel, A Critical Dissertation on the Nature, Measures, and Causes of Value; Chiefly in Reference to the Writings of Mr. Ricardo and His Followers By the Author of Essays on the Formation and Publication of Opinions, London, 1825, p. 72. -- Ed. ]