This leads on to the idea that there is a 'natural' or 'neutral' or equilibrium' rate of interest, namely, that rate of interest which equates investment to classical savings proper without any addition from 'forced savings'; and finally to what, assuming they are on the right track at the start, is the most obvious solution of all, namely, that, if the quantity of money could only be kept constant in all circumstances, none of these complications would arise, since the evils supposed to result from the supposed excess of investment over savings proper