One might have expected that Keynes' General Theory, insofar as it examines how various shocks would impact on an economy in which the money supply does not expand and new plant can be bought but not put into use, could hardly serve as the basis for political initiatives. Nothing could be further from the truth. In order for something like Keynes' theory to serve as a guide to policymaking it is necessary for Keynes' short term model to be extended to a medium term model, in which more variables are subject to change. Keynes offers no clue as to how, for instance, the medium term rate of profit on marginal capital might show the same tendency to decline as the short term rate of profit. He certainly does offers policy makers encouragement to use his theory in precisely this way.
Keynes believes that output and employment can be increased if capitalists are prepared to produce at a lower rate of interest. The increased employment of available resources, including labour, ought can be thought of as a general improvement. Keynes thinks this reduction in the operative rate of interest can be effected in two ways:
1. Increasing the propensity to invest at every rate of interest - shifting schedule "N" down and to the right
2. Increasing the propensity to consume at every level of income - shifting schedule "S" down and to the left
These are surely long term or medium term goals for an administration, and incorporating these changes into Keynes' short term model is, at best, stretching a point. Keynes' model implicitly rules out the use of new industrial plant, and the effect of this increase in capacity on output and interest, as beyond its scope. This feature of capitalist production is excised for formal reasons, even though policy proposals are made, the efficacy of which certainly depend on the growth path of capitalist production.
The ideas mentioned above about psychological propensities to save or invest are the basis for Keynes' reverie about ancient Egypt, which:
"was doubly fortunate, and doubtless owed to this its fabled wealth, in that it possessed two activities, namely, pyramid-building as well as the search for precious metals, the fruits of which, since they could not serve the needs of man by being consumed, did not stale with abundance".
This is probably only half serious, because ancient Egypt evidently was not a fancy dress version of bourgeois England. Keynes' point is that the relatively low amount of saving in ancient Egypt, i.e. hoarding of gold, would have reduced "the interest rate", whatever that was, and increased output. This counterfactual story is not just picturesque, however, because it serves as a rhetorical support for the most celebrated keynesian policy: wholly wasteful loan expenditure.