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- Ockham's Theory of
Terms: Part 1 of the Summa Logicae, Translated and Introduced by Michael
J. Loux (Notre Dame, Indiana: University of Notre Dame Press, 1974).
- Ogden, C. K.
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- Oppenheim, P.
- (and Carl Hempel) "Studies in the Logic of Explanation," Philosophy of Science 15, 1948.
- Osborne, H.
- "Definition of Value," Philosophy 6, 1931.
- Foundations of the Philosophy of Value (Cambridge, 1933).
- Owen, Joseph
- The Doctrine of Being in the Aristotelian Metaphysics (Toronto: Pontifical Institute of Medieval Studies, 1957).