DEFINITION OF METAPHYSICS -- ITS UTILITY AND DIVISION.
1. Real Philosophy, or Metaphysics, is that part of Philosophy which treats of that which is immaterial and supersensible in real being. -- Rational Philosophy treats of entities as they are in the order of cognition; Metaphysics studies them as they are in themselves.
2. The excellence of Metaphysics is seen both from its own nature and from its relations to other sciences. -- The natural sciences, mathematics, and other sciences treat only of this or that being and under a particular aspect; they are, therefore, subordinate to metaphysics, which studies being in its highest or ultimate causes or reasons. Although, relatively to the end of man, moral philosophy excels all the other sciences, and rational philosophy claims pre-eminence as a necessary condition for advancing in any science whatever; yet, considered absolutely, metaphysics excels both, for it is their foundation.{1} Metaphysics yields in excellence to Sacred Theology alone.
3. Metaphysics is divided into General Metaphysics, or Ontology, and Special Metaphysics. Special Metaphysics is further divided into Cosmology, Psychology, and Natural Theology. -- Being, in its most general sense, when considered in itself as Being simply, is the object of General Metaphysics, or Ontology. When contemplated in its concrete reality, it is the object of Special Metaphysics. But Being is either created or uncreated. Cosmology treats of the created world in its most general principles, leaving to the subaltern sciences the study of particular things. Yet as man occupies a place apart in creation, the study of the human soul forms a separate branch of special metaphysics, and is called Psychology. Lastly, the study of God and His attributes is the object of Natural Theology.
{1} The inferior sciences neither prove their first principles nor defend them against attack; this they leave to a superior science, i.e metaphysics. Cf. St. Thomas, Sum. Th. i, q. i, a. 8.