Ontology (philosophy): the study of being, existence, and reality

The term ontology seems to have been first used in German by Rudolf Goclenius (1547-1628). At about the same time there is a reference in Jacob Lorhard (1561-1609), professor in St. Gallen, Switzerland. Johann Georg Walch (1693-1775) defines in his work Philosophisches Lexicon: "Ontology means the doctrine of the end [being], and is a designation by which some recent philosophers understood the science dealing with the end in general and its properties." Walch points out that "others prefer to say ontosophy."

The term "ontology" was first used in its proper sense (doctrine of being) by Rudolf Goclenius in 1613 and by Johannes Clauberg in 1656. Rudolf Goclenius separates ontology and metaphysics.

In the classical philosophical system (which goes back to Christian Wolff, among others) ontology represents a part of metaphysics, namely general metaphysics (metaphysica generalis) in contrast to special metaphysics (metaphysica specialis), which deals with God (natural theology), the soul (natural psychology) and the world (natural cosmology).

With special metaphysics is connected the claim to investigate certain areas of entities on the basis of reason alone (i.e. non-empirically): Natural theology, for example, contrasts with forms of theology based on revelation, on "sacred writings"; natural cosmology contrasts with empirical physics. Typical questions of a special metaphysics are, for example, the problems whether the world has a beginning in time or whether the soul is immortal.

In the course of history, various phenomena or topics have emerged that are the subject of philosophical or more general scientific discussions, and which can be called the basic questions of ontology:

• the question of existence, which is a characteristic of every being or is questioned as being in itself.
• the problem of totality, of unity in multiplicity, of the (causal) connection of complex entities.
• the distinction between things, constructs, processes, states and events-      
• the dynamic development of material systems, connected with the duality of being and becoming
• the numerical equality or difference, the problem of individuation.
• the question of relationships or relations or structural connections.
• the problem of identity or persistence and change over time.
• the issue of qualitative sameness and difference, the question of the general or the particular, also known as the problem of universals.