" Another, more fluid metaphor for the world of thought gradually suggested itself to him, derived from his former voyages at sea. A philosopher who was trying to consider human understanding in all its aspects would behold beneath him a mass molded in calculable curves, streaked by currents which could be charted, and deeply furrowed by the pressure of winds and the heavy, inert weight of water. It seemed to him that the shapes which the mind assumes are like those great forms, born of undifferentiated water, which assail or replace each other on the surface of the deep; each concept collapses, eventually, to merge with its very opposite, like two waves breaking against each other only to subside into the same single line of white foam. "

― Marguerite Yourcenar , L'Œuvre au noir