The world is just what it is because the will, whose manifestation it is, is what it is, because it so wills.
 Arthur Schopenhauer, The World as Will and Representation (1819). copy citation

add
Author Arthur Schopenhauer
Source The World as Will and Representation
Topic world
Date 1819
Language English
Reference
Note Translated by R. B. Haldane and J. Kemp
Weblink http://www.gutenberg.org/files/38427/38427-h/38427-h.html

Context

“The world exists as the mirror of this assertion, with innumerable individuals in infinite time and space, in infinite suffering, between generation and death without end. Yet from no side is a complaint to be [pg 427] further raised about this; for the will conducts the great tragedy and comedy at its own expense, and is also its own spectator. The world is just what it is because the will, whose manifestation it is, is what it is, because it so wills. The justification of suffering is, that in this phenomenon also the will asserts itself; and this assertion is justified and balanced by the fact that the will bears the suffering. Here we get a glimpse of eternal justice in the whole:” source