“Philosophers have only interpreted the world, in various ways; the point, however, is to change it.” This famous 11th thesis from Karl Marx’s Theses on Feuerbach is engraved on his tombstone in Highgate Cemetery in London.

It was meant to be a refutation of another famous saying, by G.W.F. Hegel: “The owl of Minerva takes flight only when darkness falls.”

This poetic but enigmatic remark is from the Philosophy of Right. It means understanding always arrives too late; philosophy can only teach about the past, never the future: “When philosophy paints its grey on grey, then has a form of life grown old, and with grey on grey it cannot be rejuvenated, but only known; the Owl of Minerva first takes flight with twilight closing in.”