“Anxiety is love’s greatest killer,” Anaïs Nin famously wrote. But what, exactly, is anxiety, that pervasive affliction the nature of which remains as drowning yet as elusive as the substance of a shadow? In his 1844 treatise The Concept of Anxiety (public library), Danish philosopher Søren Kierkegaard (May 5, 1813–November 11, 1855) explains anxiety as the dizzying effect of freedom, of paralyzing possibility, of the boundlessness of one’s own existence — a kind of existential paradox of choice. He writes:

Anxiety is a qualification of dreaming spirit, and as such it has its place in psychology. Awake, the difference between myself and my other is posited; sleeping, it is suspended; dreaming, it is an intimated nothing. The actuality of the spirit constantly shows itself as a form that tempts its possibility but disappears as soon as it seeks to grasp for it, and it is a nothing that can only bring anxiety. More it cannot do as long as it merely shows itself. [Anxiety] is altogether different from fear and similar concepts that refer to something definite, whereas anxiety is freedom’s actuality as the possibility of possibility. […] Anxiety may be compared with dizziness. He whose eye happens to look down the yawning abyss becomes dizzy. But what is the reason for this? It is just as much in his own eye as in the abyss, for suppose he had not looked down. Hence, anxiety is the dizziness of freedom, which emerges when the spirit wants to posit the synthesis and freedom looks down into its own possibility, laying hold of finiteness to support itself. Freedom succumbs to dizziness. Further than this, psychology cannot and will not go. In that very moment everything is changed, and freedom, when it again rises, sees that it is guilty. Between these two moments lies the leap, which no science has explained and which no science can explain. He who becomes guilty in anxiety becomes as ambiguously guilty as it is possible to become.

He captures the invariable acuteness of anxiety’s varied expressions:

Anxiety can just as well express itself by muteness as by a scream.

Kierkegaard argues that, to paraphrase Henry Miller, on how we orient ourselves to anxiety depends the failure or fruitfulness of life:

In actuality, no one ever sank so deep that he could not sink deeper, and there may be one or many who sank deeper. But he who sank in possibility — his eye became dizzy, his eye became confused… Whoever is educated by possibility is exposed to danger, not that of getting into bad company and going astray in various ways as are those educated by the finite, but in danger of a fall, namely, suicide. If at the beginning of education he misunderstands the anxiety, so that it does not lead him to faith but away from faith, then he is lost. On the other hand, whoever is educated [by possibility] remains with anxiety; he does not permit himself to be deceived by its countless falsification and accurately remembers the past. Then the assaults of anxiety, even though they be terrifying, will not be such that he flees from them. For him, anxiety becomes a serving spirit that against its will leads him where he wishes to go.

Core to this premise is the conception of anxiety as a dual force that can be both destructive and generative, depending on how we approach it. Like Nin herself observed in her reflection of why emotional excess is necessary for writing, Kierkegaard argues that anxiety is essential for creativity. Perhaps the most enduring and thoughtful interpretation of his treatment of the relationship between creativity and anxiety comes from legendary existential psychologist Rollo May’s The Meaning of Anxiety (public library), originally published in 1950:

We can understand Kierkegaard’s ideas on the relation between guilt and anxiety only by emphasizing that he is always speaking of anxiety in its relation to creativity. 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.

Both The Concept of Anxiety and The Meaning of Anxiety endure as excellent reads in their entirety, timeless and increasingly timely in our age of anxious wonder.