Frege's notion of sense is somewhat obscure, and neo-Fregeans have come up with different candidates for its role.Sam Cumming, Names, Stanford Encyclopedia of Philosophy 2013. Accounts based on the work of CarnapMeaning and Necessity, Chicago: University of Chicago Press, 1947. and Church“A Formulation of the Logic of Sense and Denotation”, in P. Henle, M. Kallen, and S. K. Langer, eds., Structure, Method, and Meaning, New York: Liberal Arts Press, 1951 treat sense as an intension, or a function from possible worlds to extensions. For example, the intension of ‘number of planets’ is a function that maps any possible world to the number of planets in that world. John McDowell supplies cognitive and reference-determining roles.McDowell, J., “On the Sense and Reference of a Proper Name”, Mind, 86: 159–85, 1977. Michael Devitt treats senses as causal-historical chains connecting names to referents, allowing that repeated "groundings" in an object account for reference change.Devitt, M., Designation, New York: Columbia University Press, 1981.
