The Shift of Aspect in Language and Thought
- Examines the role of this ubiquitous but neglected feature of expression and perception, suggesting that by a shift of aspect reality is both mental and physical.
- http://www.shift-of-aspect-in-language-and-thought.net

PhilSci Archive: Idealist Philosophy: What is Real ?
- Paper by Axel Randrup defending idealism and arguing that materialism leads to logical contradictions, which closes by considering the implications of this for religion.
- http://philsci-archive.pitt.edu/archive/00001216/01/reality.html

Stanford Encyclopedia of Philosophy: Existence
- Survey article by Barry Miller.
- http://plato.stanford.edu/entries/existence/

Metaphysics of Quality
- Robert M. Pirsig deals with the fundamentals of existence and attempts to provide a more coherent system for understanding reality than current paradigms allow.
- http://www.moq.org/

Why Does Anything Exist?
- Sequence of short essays on this topic.
- http://www.hedweb.com/nihilism/

What is Ontology?
- Collected definitions, from leading philosophical reference works and from philosophers from Wolff to Husserl.
- http://www.formalontology.it/section_4.htm

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.
- http://plato.stanford.edu/entries/qualia-knowledge/

Stanford Encyclopedia of Philosophy: Abstract Objects
- Survey of attempts to draw the distinction between concrete and abstract objects; by Gideon Rosen.
- http://plato.stanford.edu/entries/abstract-objects/

Stanford Encyclopedia of Philosophy: Physicalism
- Discussion of the thesis that everything is physical; by Daniel Stoljar.
- http://plato.stanford.edu/entries/physicalism/

Stanford Encyclopedia of Philosophy: Events
- Survey of philosophical views on the character and status of events; by Roberto Casati and Achille Varzi.
- http://plato.stanford.edu/entries/events/

Stanford Encyclopedia of Philosophy: Holes
- An interesting case-study for ontologists and epistemologists.
- http://plato.stanford.edu/entries/holes/

Ontology. A Resource Guide for Philosophers
- Resources on the development of ontology, especially in the twentieth century.
- http://www.formalontology.it/

Stanford Encyclopedia of Philosophy: Tropes
- An article describing tropes; by John Bacon.
- http://plato.stanford.edu/entries/tropes/

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.
- http://plato.stanford.edu/entries/identity-indiscernible/

Buffalo Ontology Site
- Information on ontology, on the history of ontology, and on contemporary ontology and its applications.
- http://wings.buffalo.edu/philosophy/ontology/