Not sadness but structural misrelation — the self failing to relate honestly to itself, either refusing to be who it is (weakness) or attempting total self-authorship (defiance), often invisible to the sufferer.
In The Sickness Unto Death, Kierkegaard defines despair as the fundamental disorder of selfhood — not an emotion but a structural condition in which the self has failed to relate properly to its own existence. Because the self is constituted through the ongoing activity of relating to itself, despair is the breakdown of that activity. Kierkegaard identifies two primary forms: the despair of weakness, in which the person refuses to be the particular, limited self her circumstances have produced, and the despair of defiance, in which she attempts to create herself from nothing, denying the conditions she did not choose. Most unsettling is his claim that despair is often invisible — a person can be productive, successful, admired, and utterly despairing because genuine selfhood has been abandoned for a performance.
Despair (Kierkegaard)
In The You On AI Field Guide
The concept emerges from Kierkegaard's anthropology of the self as fundamentally relational and dynamic. Unlike Cartesian models treating the self as