After some thought, my conjecture is, maybe:
If everything works out as Keynes postulate, an injection by investment will first increase T (which is equal to C + I + G + X-M) (or Y, if using MV = PY), then V will increase in response, reflecting the 1st round of the multiplier effect, then, increasing C (which is in T or Y also), which in effect increases V again in the 2nd round of the multiplier process, henceforth increasing C again, and so on. Keynes argue that MV and PT (or PY) will in this way both be pushed to higher levels, reflecting economic growth.
Monetarists however think that a blatant injection of investment or government spending will increase T ( or Y) only once, because it is indeterminately inherently fixed if nothing is done to increase productivity; that this increase in I or G will then show up in V, which will also be rigid, in effect bouncing the increment to P, causing inflation.
Is this rubbish? Anyone here interested to join in the discussion or correct me?
Thanks...