> Because the total social product is a flow per unit time. If expressed
> in money it must be measured over a time interval.
Alan replies:
But anything that exists as a flow, also exists as a stock.
At any time, we can identify quite determinately and indeed, physically,
everything that is being offered for sale. It's a perfectly definite thing,
as is its monetary measure.
I agree that we can also identify the flows into this product per unit
time. And the flows out of it.
Its size at any moment is the time-integral of the difference between these
two flows, plus a constant of integration which is its stock at any
definite starting point.
In like manner, if we have a tub of water being filled by a tap, and
emptied by a plughole, then there are flows of water in and out of the tub.
The fact that the water is flowing does not negate the existence of a
definite water level at every definite point in time.
Alan