b. 1952
Edward N. Zalta is an American philosopher and senior research scholar at Stanford University, best known for developing Axiomatic Metaphysics (object theory) and for founding and directing the Stanford Encyclopedia of Philosophy (SEP), one of the most important open-access reference works in philosophy.
Founded and directs the Stanford Encyclopedia of Philosophy (SEP)
Developed axiomatic object theory (Abstract Objects: An Introduction to Axiomatic Metaphysics, 1983)
Advanced a neo-Meinongian theory of abstract and nonexistent objects
Formalized Leibniz's and Descartes' ontological arguments using object theory
Contributed to formal epistemology and the philosophy of mathematics
Being abstract is not simply the negation of being concrete.
premiseSome objects are not currently concrete but are possibly concrete.
premiseNumbers, sets, and similar objects are not the kind of thing that could be concrete.
claimAbstract objects necessarily lack causal powers.
claimOrdinary objects include both actually concrete objects and possible objects that are not in fact concrete but could have been.
premiseAbstract objects are, by definition, not concrete at any possible world.
premiseNecessarily, anything with causal powers is concrete (□∀x(Cx → E!x)).
premiseIf abstract meant merely 'not concrete', then abstractness would be compatible with possible concreteness, which fails to capture the modal status of mathematical objects.
premiseActual existence (E!x) implies possible existence (◇E!x).