Marx on the positive-feedback dynamic of capitalism, describing the generalized expansionary pulsion as a “metabolism”:
Since money as universal material representative of wealth emerges from circulation, and is as such itself a product of circulation, both of exchange at a higher potentiality, and a particular form of exchange, it stands therefore in the third function as well, in connection with circulation; it stands independent of circulation, but this independence is only its own processes. It derives from it just as it returns to it again. Cut off from all relation to it, it would not be money, but merely a natural object, gold or silver. In this character it is just as much its precondition as its result. Its independence is not the end of all relatedness to circulation, but rather a negative relation to it. This comes from its independence as a result of M-C-C-M. In the case of money as capital, money is posited as (1) a precondition of circulation as well as its result; (2) as having independence only in the form of a negative relation, but always a relation to circulation; (3) as itself an instrument of production, since circulation no longer appears in its primitive simplicity, as quantitative exchange, but as a process of production, as a real metabolism. And thus money is itself stamped as a particular moment of this process of production.
(from Grundrisse, pgs. 216-217)