Theory of being as such.
It was originally called "first philosophy" by Aristotle . In the 18th century David Hume and Immanuel Kant . Ontology was revived in the early 20th century by practitioners of phenomenology and existentialism , notably Edmund Husserl and his student Martin Heidegger . In the English-speaking world, interest in ontology was renewed in the mid-20th century by W.V.O. Quine ; by the end of the century it had become a central discipline of {{link=analytic philosophy">analytic philosophy . See also idealism ; realism ; universal .