On the Fourfold Root of the Principle of Sufficient Reason

Schopenhauer's analyses of causation and related concepts . . . rival and probably surpass in their depth and brilliance the more celebrated discussions of David Hume. Where Hume grossly oversimplified these problems and left them riddled with paradoxes, Schopenhauer disentangled them and shed light on what had seemed hopelessly dark. --Richard Taylor, University of Rochester