What Are The Limitations Of The Quantity Theory?

There are many criticisms on the quantity theory. First of all there is no direct and appropriate relationship. The relationship between the quantity of money and the price level is not direct and proportionate relationship. The relationship between the quantity of money and the price level is not direct and proportionate as assumed in Fisher's theory.  The second thing is the static theory. The theory assumes that the changes in supply of money do not affect V and T which are independent variables. The fact is that in the real life, these variables do not remain constant. This theory also considers the assumption of full employment. The theory is based on the assumption of full employment which is unrealistic. According to Keynes, full employment in a capitalistic economy is rare situation. The economy normally operates at less then full employment.  In the quantity theory of Fisher's the influence of the rate of interest on the money supply and the level of prices has been completely ignored. The fact is that an increase or decrease in money supply has an important  bearing on the rate of interest an increase in money supply leads to a decline in the rate of interest and vice versa.