The best collection of online articles in linguistics, especially formal semantics, and neighboring areas of interest to philosophers is Institute for Logic, Language and Computation Publications , where you can find such important articles as Theo Janssen s article on Compositionality and Groenendijk and Stokhof s article on Dynamic Montague Grammar. There is also a good collection of Semantics Web Resources . Such important modern ontologists as Barry Smith and Peter Simons , who have studied the formal ontology of parts and wholes and dependency relations, and Achille C. Varzi have their own homepages. Barry Smith's homepage is especially noteworthy, since you can download many of his articles from it. Another philosopher on the borderline with far wilder ideas is Alan Randall .
Philosophy of mind is one of the most interesting areas of ontology.
David Chalmers has assembled a good collection of links to Online Papers on Consciousness . The articles of Chalmers himself are among the most interesting modern treatments of the psychophysical problem. The Cognitive Sciences Eprint Archive is also a useful resource for philosophy of mind. There is also a good collection of Classics in the History of Psychology . Williams James s Principles of Psychology and Wilhelm Wundt s Outlines of Psychology.