This is the first solution which Marx gave to the problem of the accumulation of the aggregate capital. Having dwelt on this aspect of the question already in volume i of Capital, Marx returns to the problem at the end of the second volume of his main work whose concluding 21st chapter is devoted to accumulation and enlarged reproduction of the aggregate capital.

Let us examine Marx’s diagrammatic exposition of accumulation more closely. On the model of the diagram of simple reproduction with which we are already familiar, he devised a diagram for enlarged reproduction, the difference appearing most clearly if we compare the two.

Assuming that society’s annual aggregate product can be represented by an amount to the value of 9,000 (denoting millions of working hours, or, in capitalist monetary terms, any arbitrary amount of money), the aggregate product is to be distributed as follows:

I.4,000c+1,000v+1,000s=6,000
II.2,000c+500v+500s=3,000
Total:9,000

Department I represents means of production, Department II consumer goods. One glance at the proportion of the figures shows that in this case simple reproduction alone is possible. The means of production made in Department I equal the total of the means of production actually used by the two departments. If these are merely renewed, production can be repeated only on its previous scale. On the other hand, the aggregate product of Department II equals the total of wages and surplus value in both departments. This shows that the consumer goods available permit only the employment of just as many workers as were previously employed, and that the entire surplus value is similarly spent on consumer goods, i.e. the personal consumption of the capitalist class.

Now let us take the same aggregate product of 9,000 in the following equation:

I.4,000c+1,000v+1,000s=6,000
II.1,500c+750v+750s=3,000
Total:9,000

Here a double disproportion confronts us: 6,000 means of production are created—more than those which are actually used by the society, i.e. 4,000c + 1,500c, leaving a surplus of 500. Similarly, less consumer goods (3,000) are produced than the sum of what is paid out in wages (i.e. 1,000v + 750v, the requirement of the workers), plus the aggregate of surplus value that has been produced (1,000s + 750s). This results in a deficit of 500. Since our premises do not allow us to decrease the number of workers employed, the consequence must be that the capitalist class cannot consume the entire surplus value it has pocketed. This proves fully consistent with the two material preconditions of enlarged reproduction on a capitalist basis: part of the appropriated surplus value is not to be consumed but is used for the purposes of production; and more means of production must be produced so as to ensure the use of the capitalised surplus value for the actual expansion of reproduction.

In considering the diagram of simple reproduction, we saw that its fundamental social conditions are contained in the following equation: the aggregate of means of production (the product of Department I) must be equivalent to the constant capital of both departments, but the aggregate of consumer goods (the product of Department II) must equal the sum of variable capitals and surplus values of the two departments. As regards enlarged reproduction, we must now infer a precise inverse double ratio. The general precondition of enlarged reproduction is that the product of Department I must be greater in value than the constant capital of both departments taken together, and that of Department II must be so much less than the sum total of both the variable capital and the surplus value in the two departments.

This, however, by no means completes the analysis of enlarged reproduction; rather has it led us merely to the threshold of the question. Having deduced the proportions of the diagram, we must now pursue their further activities, the flow of circulation and the continuity of reproduction. Just as simple reproduction may be compared to an unchanging circle, to be repeated time and again, so enlarged reproduction, to quote Sismondi, is comparable to a spiral with ever expanding loops. Let us begin by examining the loops of this spiral. The first general question arising in this connection is how actual accumulation proceeds in the two departments under the conditions now known to us, i.e. how the capitalists may capitalise part of their surplus value, and at the same time acquire the material prerequisites necessary for enlarged reproduction.