Abstract:
The doctrine of a metaphysical realism of properties, relations, and propositions (PRPs) is one of the two basic tenets of this book. The other is that unlike set theory the theory of PRPs is a genuine part of logic and simultaneously a foundation for philosophy, psychology, theory of language, and mathematics. Two views of PRPs as intentional entities are distinguished: one according to which PRPs are identical if and only if they are necessarily equivalent; the other maintaining that intentional entities are either complex or simple and that each complex PRP has a unique, non-circular ultimate analysis in terms of simple PRPs and certain fundamental logical operations. The first conception is appropriate in the treatment of modality and the second is appropriate in the analysis of intentionality and the theory of meaning.
