In his most important contribution to the Heidelberg school, a founder of existentialism critiques the scientific aspirations of psychotherapy.

In 1910, Karl Jaspers wrote a seminal essay on morbid jealousy in which he laid the foundation for the psychopathological phenomenology that through his work and the work of Hans Gruhle and Kurt Schneider, among others, would become the hallmark of the Heidelberg school of psychiatry. In General Psychopathology, his most important contribution to the Heidelberg school, Jaspers critiques the scientific aspirations of psychotherapy, arguing that in the realm of the human, the explanation of behavior through the observation of regularity and patterns in it (Erklärende Psychologie) must be supplemented by an understanding of the "meaning-relations" experienced by human beings (Verstehende Psychologie).