On the Fourfold Root of the Principle of Sufficient Reason

Arthur Schopenhauer was a German philosopher best known for his book, The World as Will and Representation. The writings of German philosopher were a profound influence on art and aesthetics, music and literature in the 19th century. 

The principle of sufficient reason is a powerful and controversial philosophical principle stipulating that everything must have a reason or cause. Arthur Schopenhauer took the Kantian concept that all knowledge derives from experience and broadened it to conclude that our experience of the world is necessarily subjective and influenced by our own intellect and biases, and that reality is but an extension of our own will. Schopenhauer revised and re-published it in 1847. This work articulated the centerpiece of many of Schopenhauer's arguments, and throughout his later works he consistently refers his readers to this short treatise as the necessary beginning point for a full understanding of his further writings.