As is well known, the method on which the dominant (marginalist or ‘neoclassical’) economic theory is based at present is constructed upon the notions of ‘temporary’ or, more frequently, ‘intertemporal’ equilibrium. In several respects these two notions differ widely from one another; they have, however, this in common: they both refer to positions of the economic system that do not imply a uniform rate of net return on the supply price of the capital goods existing in that system. In this crucial respect, therefore, the method employed today is, whatever its particular formulation, in stark contrast to the method used both by the classical economists and by the founders and the first systematisers of the marginalist theory who, in order to study value and distribution, always referred to positions of the economic system in which that uniformity - and more generally the uniformity of the rate of profit - was assured.
Trabucchi, P. (2013). Capital and Stationary States. Considerations on the Reasons Adduced for Abandoning the Method of Normal Positions. In A.P. Enrico Sergio Levrero (a cura di), Sraffa and the Reconstruction of Economic Theory (pp. 129-150). London : Palgrave Macmillan [10.1057/9781137316837.0013].