Metaphysics is the branch of philosophy concerned with the fundamentals of existence or reality. Although it takes its name merely from the title an early compiler gave a volume of Aristotle's essays he placed "after the Physics (meta ta phusika), many philosophers have assumed that the meta- of metaphysics has the sense of "beyond," thus regarding metaphysics as speculation concerning things that are beyond the scope of science. Positivists (see positivism) have thus denounced the study, not recognizing that their own principles were themselves strictly metaphysical. Indeed all philosophical controversies ultimately reduce to well-worn debates in metaphysics.