ABSTRACT
Let us recall once more that here, as throughout this book, Dynamics means exclusively analysis that links quantities pertaining to different points of theoretic time—in the sense that has been repeatedly explained before—and not the theory of evolutionary processes that run their courses in historic time: it is practically coextensive with sequence analysis and includes period analysis as a special case, but it is not coextensive with the theory of economic growth or development, or ‘progress.’ 1 Thus defined dynamics is a genuinely new departure. We have indeed seen at various turns of our way, particularly in the case of Sismondi, that dynamic considerations in our sense intruded into economic analysis times out of number, chiefly by implication but also explicitly. But the exact core of economics was nevertheless static and was believed to constitute a self-contained body of doctrine, a body moreover that embraced all or almost all of the essential insights. This is obvious in the case of Walras. But it also applies to Marshall. 2 He no doubt added plenty of extra-static considerations, chiefly about growth but also about sequences, so much in fact that he may be said to have posited the task of future dynamic theory (see e.g. Principles, p. 519), just as he posited the task of future econometrics; but though he presented material, viewpoints, and desiderata, he did not cross the Rubicon. For the rest, we have noticed the suggestive pointers of Pantaleoni and Pareto, but there was no advance toward the goal to which they pointed.
