Schopenhauer as the originator of Freudian metapsychology]

The influence of 19th century philosophy on Freud's thought is to this day underestimated in comparison with the influence of the scientific theories. G?dde vindicates Max Horkheimer's proposition that Freud was "in certain respects a successor to Schopenhauer" even though Freud knew Schopenhauer (and Nietzsche) through secondary literature rather than through the original writings.