Ein Mensch wie ich kann ohne Steckenpferd, ohne herrschende Leidenschaften, ohne einen Tyrannen in Schillers Worten, nicht leben. Ich habe meinen Tyrannen gefunden und in seinem Dienst kenne ich kein Maß.
Letter to Wilhelm Fliess (1895), as quoted in Journal of the History of the Behavioral Sciences Vol 3-4 (1967) p. 159
1890s
Context: A man like me cannot live without a hobby-horse, a consuming passion — in Schiller's words a tyrant. I have found my tyrant, and in his service I know no limits. My tyrant is psychology. it has always been my distant, beckoning goal and now since I have hit upon the neuroses, it has come so much the nearer.