Lonergan’s basic terms are velocities. There is a shift to dynamics. P. McShane called the creative shift from Walrasian macrostatics to macroeconomic dynamics the Leibnitz-Newtonian shift.
Please see under Key Notions the subtopic with the lengthy title: The Leibnitz-Newtonian Shift of Context and Scientific Economics; Basic Terms, Explanatory Conjugates, An adequate Level of Abstraction, No Premature Introduction of Boundary Conditions.
Taking into account past and (expected) future values does not constitute the creative key transition to dynamics. Those familiar with elementary statics and dynamics (in physical mechanics) will appreciate the shift in thinking involved in passing from equilibrium analysis (of a suspended weight or a steel bridge)…to an analysis where attention is focused on second-order differential equations, on d2θ/dt2, d2x/dt2, d2y/dt2, on a range of related forces, central, friction, whatever. Particular boundary conditions, “past and future values” are relatively insignificant for the analysis. What is significant is the Leibnitz-Newtonian shift of context. [McShane, 1980, 127]
Note that the vertical axis of the Figure 24-7 below represents the accelerations: dQ’/Q’ and dQ”/Q”. Q’ and Q” represent velocities. The title underneath the Figure 24-7 fails to apply the proper superscript to surplus activity. Also, k-1 might be, for example 1.05-1 or .05 or 5% or a geometric increase period after period, while (1/r – 1)Q1 might be !/.95 – 1)100 or (1.05263-1)100 or (.05263)100 or 5.263 which would be a constant magnitude period after period and, therefore, a declining percent period after period. Thus the title indicating the Rate of Change of a percentage change.
Lonergan’s basic terms are velocities and their changes. There is a shift to dynamics. P. McShane called the creative shift from Walrasian macrostatics to macroeconomic dynamics the Leibnitz-Newtonian shift. Again,
In Lonergan’s circulation analysis, the basic terms are rates – rates of productive activities and rates of payments. The objective of the analysis is to discover the underlying intelligible and dynamic (accelerative) network of functional, mutually conditioning, and interdependent relationships of these rates to one another. [CWL 15 26-27 ftnt 27]