Ernst Brücke

Austrian physiologist and Freud's laboratory director at the University of Vienna, who instilled in Freud the mechanistic-reductionist scientific program of the Helmholtz school — the intellectual framework Freud later struggled to apply to the mind.

Represented the 19th-century Helmholtz program of reducing biological phenomena to physico-chemical forces — the scientific worldview that Freud absorbed and then tried to apply to psychology in his never-published Project for a Scientific Psychology.