Hence Kierkegaard and Nietszche and Camus and Sartre have proclaimed that courage is not the absence of despair; it is, rather, the capacity to move ahead in spite of despair.

Because it is possible to create — creating one’s self, willing to be one’s self, as well as creating in all the innumerable daily activities (and these are two phases of the same process) — one has anxiety. One would have no anxiety if there were no possibility whatever. Now creating, actualizing one’s possibilities, always involves negative as well as positive aspects. It always involves destroying the status quo, destroying old patterns within oneself, progressively destroying what one has clung to from childhood on, and creating new and original forms and ways of living. If one does not do this, one is refusing to grow, refusing to avail himself of his possibilities; one is shirking his responsibility to himself. Hence refusal to actualize one’s possibilities brings guilt toward one’s self. But creating also means destroying the status quo of one’s environment, breaking the old forms; it means producing something new and original in human relations as well as in cultural forms (e.g., the creativity of the artist). Thus every experience of creativity has its potentiality of aggression or denial toward other persons in one’s environment or established patterns within one’s self. To put the matter figuratively, in every experience of creativity something in the past is killed that something new in the present may be born. Hence, for Kierkegaard, guilt feeling is always a concomitant of anxiety: both are aspects of experiencing and actualizing possibility. The more creative the person, he held, the more anxiety and guilt are potentially present.

Intense fatigue or illness may also weaken the control of the cortex. Hence we find tired or sick persons responding to threats with a greater degree of undifferentiated anxiety. In psychoanalytic terms, we would speak of this as regression.