Buffalo Ontology Site - Information on ontology, on the history of ontology, and on contemporary ontology and its applications. Stanford Encyclopedia of Philosophy: The Identity of Indiscernibles - A principle of analytic ontology first explicitly formulated by Leibniz. It states that no two distinct substances exactly resemble each other. Stanford Encyclopedia of Philosophy: Tropes - An article describing tropes; by John Bacon. Stanford Encyclopedia of Philosophy: Holes - An interesting case-study for ontologists and epistemologists. Stanford Encyclopedia of Philosophy: Events - Survey of philosophical views on the character and status of events; by Roberto Casati and Achille Varzi. Stanford Encyclopedia of Philosophy: Physicalism - Discussion of the thesis that everything is physical; by Daniel Stoljar. Stanford Encyclopedia of Philosophy: Abstract Objects - Survey of attempts to draw the distinction between concrete and abstract objects; by Gideon Rosen. Qualia: The Knowledge Argument - Aims to establish that conscious experience involves non-physical properties. It is one of the most discussed arguments against physicalism; from the Stanford Encyclopedia by Martine Nida-Rümelin. Why Does Anything Exist? - Sequence of short essays on this topic. Stanford Encyclopedia of Philosophy: Existence - Survey article by Barry Miller. Dualism and the Shift of Aspect in Language and Thought - Examines the bearing of the shift of aspect in language and thought on mind/world dualism, and other intractable difficulties affecting the nature of relation, change, reality, meaning and knowledge. Theory and History of Ontology - Resources on the development of ontology, especially in the twentieth century. What is Ontology? - Collected definitions, from leading philosophical reference works and from philosophers from Wolff to Husserl.