254 THE GENERAL THEORY OF EMPLOYMENT bk. iv

a recession unless there are compensating changes inother factors.

For this reason, even those degrees of recovery andrecession, which can occur within the limitationsset by our other conditions of stability, will be likely,if they persist for a sufficient length of time and are notinterfered with by changes in the other factors, to causea reverse movement in the opposite direction, until thesame forces as before again reverse the direction.

Thus our four conditions together are adequate toexplain the outstanding features of our actual experi-ence;—namely, that we oscillate, avoiding the gravestextremes of fluctuation in employment and in prices inboth directions, round an intermediate position appreci-ably below full employment and appreciably above theminimum employment a decline below which wouldendanger life.

But we must not conclude that the mean position thusdetermined by “natural” tendencies, namely, by thosetendencies which are likely to persist, failing measuresexpressly designed to correct them, is, therefore, estab-lished by laws of necessity. The unimpeded rule ofthe above conditions is a fact of observation concerningthe world as it is or has been, and not a necessary prin-ciple which cannot be changed.