I did not know this:
In Einstein’s study in Berlin in the 1920s, three portraits hung on the wall: Michael Faraday, James Clerk Maxwell, and Arthur Schopenhauer.
I learned that from Don Howard’s fascinating “A Peek behind the Veil of Maya” (pdf).
Schopenhauer’s pessimism was extreme. Reality, he wrote in The World as Will and Representation, is a “world of constantly needy creatures who continue for a time merely by devouring one another, pass their existence in anxiety and want, and often endure terrible affliction, until they fall at last into the arms of death” (p. 349). And more: “we have not to be pleased but rather sorry about the existence of the world, that its non-existence would be preferable to its existence” (p. 576). As for mankind: “nothing else can be stated as the aim of our existence except the knowledge that it would be better for us not to exist” (p. 605).
For what Einstein admired in the great life-denier, check out Howard’s essay. (Thanks to Professor Fred Seddon for recommending it to me.)