The essence of my thesis is that the principle of homeostasis or steady state maintenance can be applied to psychological phenomena and psycho-analytic theory. The functions of the ego in receiving external and internal stimuli and in dealing with them for the best interests of the organism can be viewed as those of a homeostatic effector. The constructive and destructive drives of the organism must be so directed and modified as to permit the maintenance of a level of tension which is both tolerable and conducive to safe, productive, and satisfying living and continued growth.

Events constantly occur which tend to disturb the adjustments and reconciliations achieved, and these stresses require the ego to improvise adaptive expedients for maintaining the integrity of the organism. Minor stresses are usually handled by relatively minor, 'normal', 'healthy' devices. Greater stresses or prolonged stress excite the ego to increasingly energetic and expensive activity in the interests of homeostatic maintenance.