The economic process is always the current, purely-dynamic, concrete functioning. The analysis of the dynamic process is always relevant to the present fact. The immanent intelligibility of such a dynamic, ever-varying process may itself be an invariant; i.e. though the differentials may change in magnitude, the relation of the differential velocities and accelerations among themselves is invariant.  So it is in the case of dynamic pendular motion, elliptic motion, the variables of electromagnetic phenomena, and in the dynamic economic process.  The general laws of the process are applicable in any instance.  These primary, abstract, general, field-theoretic laws may be applied to whatever may be the secondary determinations from the concrete non-systematic manifold.  Thus we can get the particular law explaining the particular concrete process under investigation.

The overall economic functioning has an objective immanent intelligibility.  This intelligibility is an invariant – a set of differential equations which implicitly define the explanatory, conjugate, differentials of the dynamic process. The explanatory terms are abstract functions defined by their functional relations to one another. In the implicit equations, the terms define the relations and the relations define the terms, and insight fixes both. And the equations cohere with one another to constitute a fully-explanatory field theory.

The point-to-line and higher correspondences are based upon the indeterminacy of the relation between certain (surplus) products and the (later ultimate basic) products that (exit the process and eventually) enter into the standard of living. … the indeterminacy is very much a present fact.  One has to await the future to have exact information.   And while estimates in the present may be esteemed accurate, the future has no intention of being ruled by them: owners do not junk equipment simply because it has outlasted the most reliable estimates; nor are bankrupts kept in business because their expectations, though mistaken, are proved to have been perfectly reasonable.  The analysis that insists on the indeterminacy is the analysis that insists on the present fact: estimates and expectations are proofs of the present indeterminacy and attempts to get round it; and, to come to the main point, an analysis based on such estimates and expectations can never arrive at a criticism of them; it would move in a vicious circle.  It is to avoid that circle that we have divided the process in terms of indeterminate point-to-line and point-to-surface and higher correspondences. [CWL 15, 27-28]

in the long run, and especially in the very long run, such a correlation exists.  It is that surplus production is the accelerator of basic production.  In other words the correspondence between the two is not a point-to-point but a point-to-line correspondence; … Now such a correspondence, if it is to be expressed not in terms of expectations of the future but in terms of present fact, is a correspondence of accelerator to accelerated. … If the system is to move into a long-term expansion, this movement has to begin with a surplus quantity acceleration: surplus production has not merely to maintain or renew existing capital equipment but has to reach a level at which it turns out new units of production and maintains or renews a greater number of existing units; this gives the quantity surplus expansion. [CWL 21, 132]

(there is to be discerned a threefold process in which a basic stage is maintained and accelerated by a series of surplus stages, while the needed additions to or subtractions from the stock of money in these processes is derived from the redistributive area) … The maintaining of a standard of living is attributed to a basic process (distinct process 1), an ongoing sequence of instances of so much every so often.  The maintenance and acceleration (distinct process 2) of this basic process is brought about by a sequence of surplus stages, in which each lower stage is maintained and accelerated by the next higher.  Finally, transactions that do no more than transfer titles to ownership are concentrated in a redistributive function, whence may be derived changes in the stock of money (distinct process 3) dictated by the acceleration (positive or negative) in the basic and surplus stages of the process. … So there is to be discerned a threefold process in which a basic stage is maintained and accelerated by a series of surplus stages, while the needed additions to or subtractions from the stock of money in these processes is derived from the redistributive area. … it will be possible to distinguish stable and unstable combinations and sequences of rates in the three main areas and so gain some insight into the long-standing recurrence of crises in the modern expanding economy. [CWL 15, 53-54]