"Freud remained deeply suspicious of philosophers and their speculations. Fond of repeating his conviction that psychoanalysis has little to learn from philosophy, he more than once compared philosophical systems to the delusions of paranoiacs and suggested that the primary impact of psychoanalysis on philosophy might consist in affording new insight into the personal quirks that motivate philosophical theory-building. The most common error of philosophers, he thought, is their restriction of the sphere of the mental life to conscious activity. But equally questionable is their tendency to project for themselves a seamless account of reality, their penchant for 'clinging to the illusion of being able to present a picture of the universe that is without gaps and is coherent' (SE, 22:160). Among Freud's favorite quotations was Heine's derisive caricature of the philosopher: 'With his nightcaps and the tatters of his dressing gown he patches up the gaps in the structure of the universe' (SE, 22:161)."

-Richard Boothby, Freud as Philosopher p. 283

(Illustration: Magritte, Philosopher's Lamp)