Brentano’s Ontology: From Conceptualism to Reism

It is often claimed that the beginnings of Brentano’s ontology were Aristotelian in nature; but this claim is only partially true. Certainly the young Brentano adopted many elements of Aristotle’s metaphysics, and he was deeply influenced by the Aristotelian way of doing philosophy. But he always interpreted Aristotle’s ideas in his own fashion. He accepted them selectively, and he used them in the service of ends that would not have been welcomed by Aristotle himself. The present paper is an exposition of the development of Brentano’s ontology, beginning with the Lectures on Metaphysics first delivered by Brentano in Würzburg in 1867 and concluding with his late work from 1904–1917.