But it may fluctuate for decades about a level which is chronically too high for full employment;particularly if it is the prevailing opinion that the rate of interest is selfadjusting, so that the level established by convention is thought to be rooted in objective grounds much stronger than convention, the failure of employment to attain an optimum level being in no way associated, in the minds either of the public or of authority, with the prevalence of an inappropriate range of rates of interest.