of explanation. It should be observed, and Schopenhauer himself is at
pains to point out, that his system is like a citadel with a hundred
gates: at whatever point you take it up, wherever you make your
entrance, you are on the road to the center. In this respect his
writings resemble a series of essays composed in support of a single
thesis; a circumstance which led him to insist, more emphatically even
than most philosophers, that for a proper understanding of his system it
was necessary to read every line he had written. Perhaps it would be
more correct to describe _Die Welt als Wille und Vorstellung_ as his
main thesis, and his other treatises as merely corollary to it. The
essays in this volume form part of the corollary; they are taken from a
collection published towards the close of Schopenhauer's life, and by
him entitled _Parerga und Paralipomena_, as being in the nature of
surplusage and illustrative of his main position. They are by far the
most popular of his works, and since their first publication in 1851,
they have done much to build up his fame. Written so as to be
intelligible enough in themselves, the tendency of many of them is
towards the fundamental idea on which his system is based. It may
therefore be convenient to summarize that idea in a couple of sentences;
more especially as Schopenhauer sometimes writes as if his advice had
been followed and his readers were acquainted with the whole of his
work.

All philosophy is in some sense the endeavor to find a unifying
principle, to discover the most general conception underlying the whole
field of nature and of knowledge. By one of those bold generalizations
which occasionally mark a real advance in Science, Schopenhauer
conceived this unifying principle, this underlying unity, to consist in
something analogous to that _will_ which self-consciousness reveals to
us. _Will_ is, according to him, the fundamental reality of the world,