Abstract Objects: An Introduction to Axiomatic Metaphysics (1983) is the title of a publication by Edward Zalta that outlines abstract object theory.
AOT is adual predication approach (also known as "dual copula strategy") to abstract objects[3] influenced by the contributions ofAlexius Meinong[4][5] and his studentErnst Mally.[6][5] On Zalta's account, there are two modes ofpredication: some objects (the ordinaryconcrete ones around us, like tables and chairs)exemplify properties, while others (abstract objects like numbers, and what others would call "nonexistent objects", like theround square and the mountain made entirely of gold) merelyencode them.[7] While the objects that exemplify properties are discovered through traditional empirical means, a simple set of axioms allows us to know about objects that encode properties.[8] For every set of properties, there is exactly one object that encodes exactly that set of properties and no others.[9] This allows for aformalizedontology.
In 2007, Zalta andBranden Fitelson introduced the termcomputational metaphysics to describe the implementation and investigation of formal,axiomatic metaphysics in anautomated reasoning environment.[17][18]
^Zalta, Edward N. (2004)."The Theory of Abstract Objects". The Metaphysics Research Lab, Center for the Study of Language and Information, Stanford University. RetrievedJuly 18, 2020.
^McMichael, Alan; Zalta, Edward N. (1980). "An alternative theory of nonexistent objects".Journal of Philosophical Logic.9 (3):297–313, esp. p. 313 n. 15.doi:10.1007/BF00248396.ISSN0022-3611.
^Zalta 2025, p. 258: "Some non-core λ-expressions, such as those leading to the Clark/Boolos, McMichael/Boolos, and Kirchner paradoxes, will be provably empty."
^Jesse Alama, Paul E. Oppenheimer,Edward N. Zalta,"Automating Leibniz's Theory of Concepts", in A. Felty and A. Middeldorp (eds.),Automated Deduction – CADE 25: Proceedings of the 25th International Conference on Automated Deduction (Lecture Notes in Artificial Intelligence: Volume 9195), Berlin: Springer, 2015, pp. 73–97.
José L. Falguera and Concha Martínez-Vidal; based on earlier work by Gideon Rosen (August 21, 2025)."Abstract Objects".Stanford Encyclopedia of Philosophy. RetrievedAugust 23, 2025.{{cite web}}: CS1 maint: multiple names: authors list (link)
