History of economic thought has been marked by both continuity and change, Insofar as economics as a discipline is not concerned with an undifferentiated and unhistorical reality, change is to be expected. It is the continuity-change combination which is a matter of interest and is indicative of the fact that the core of bourgeois thought is essentially a historic. The intermeshing of continuity and change in varying proportions has often had a retrogressive effect and the so-called 'revolutions' in economic theory have been followed by 'counter-revolutions' at the level of both thought and practice.