Philosophy studies the fundamental nature of existence, of man,
and of man's relationship to existence. As against the special sciences,
which deal only with particular aspects, philosophy deals with those
aspects of the universe which pertain to everything that exists. In the
realm of cognition, the special sciences are the trees, but philosophy is
the soil which makes the forest possible.
-- Ayn Rand, "Philosophy: Who Needs It," Philosophy: Who Needs It