Lambert, Karel. 1967. "Free Logic and the Concept of Existence." Notre Dame Journal of Formal Logic no. 8:133-144.
———. 1970. "Russell's Theory of Definite Descriptions." Dialectica no. 44:137-152.
———. 1972. "Being and Being So." In Jenseits Von Sein Und Nichtsein, edited by Haller, Rudolf, 37-46. Graz: Akademische Druck u. Verlagsanstalt.
———. 1974. "Impossible Objects." Inquiry no. 17:303-314.
"This paper deals with the Meinong-Russell controversy on nonsubsistent objects. The first part notes the similarity of certain contemporary semantical developments to Meinong's
theory of nonsubsistent objects. Then it lays out the major features of Meinong's famous theory, considers Russell's objections to same and Meinong's counter-objections to Russell, and argues that
Russell's well-known argument fails. However, it is possible to augment Russell's argument against Meinong with sound Russellian principles in such a way that it presents at least a strong inclining
reason against Meinong's theory of impossible objects."
———. 1974. "Predication and Extensionality." Journal of Philosophical Logic no. 3:255-264.
"Predication, writes W. V. Quine, "joins a general term and a singular term to form a sentence that is true or false according as the general term is true or false of the object, if
any, to which the singular term refers". (1) The view of predication expressed by Quine in the quoted passage is not restricted to Quine; P. F. Strawson, for example, though perhaps not a rabid
supporter of Quine's choice of words, is on record as finding the theory congenial with his own views. (2)
Quine has also written that "so long merely as the predicated general term is true of the object named by the singular term... the substitution of a new singular term that names the
same object leaves the predication true." (3) Nevertheless, most of my efforts will be directed at establishing that the theory of predication expressed in Quine's words is nonextensional.
To be precise about my quite limited objective, I need Quine's help just once more. He writes that "in an opaque construction you also cannot in general supplant a general term by a
coextensive term (one true of the same objects)... without disturbing the truth value of the containing sentence. Such a failure is one of the failures of extensionality." (4) The theory of
predication under consideration is, I claim, non-extensional in the sense that it does not satisfy the extensionality principle that coextensive general terms substitute for each other salva
veritate; proof of this claim is my major objective.
My secondary objective is to elicit some of the implications of the claim that the theory of predication under discussion is nonextensional."
(1) W. V. Quine, Word and object, Wiley, New York, 1960, p. 96
(2) P. F. Strawson, "Singular terms and predication", The Journal of Philosophy, 58 (1961).
(3) Op. cit. Word and object, pp. 142-143.
(4) Ibid., p. 151.
———. 1976. "On "the Durability of Impossible Objects"." Inquiry no. 19:251-253.
———. 1981. "On the Philosophical Foundations of Free Logic." Inquiry no. 24:147-203.
"The essay outlines the character of free logic, and motivation for its construction and development. It details some technical achievements of high philosophical interest, hut
urges that the role of existence assumptions in logic is still not fully understood, that unresolved old problems, both technical and philosophical, abound, and presents some new problems of
considerable philosophical import in free logic."
———. 1983. Meinong and the Principle of Independence. Its Place in Meinong's Theory of Objects and Its Significance in Contemporary Philosophical Logic. Cambridge:
Cambridge University Press.
———. 1986. "Nonexistent Objects: Why Theories About Them Are Important." Grazer Philosophische Studien no. 25/26:439-446.
"This essay argues for the importance of developing theories of nonexistent objects. The grounds are utility and smoothness of logical theory. In the latter case a parallel with the
theory of negative and imaginary numbers is exploited. The, essay concludes with a counterexample to a general argument against the enterprise of developing theories of nonexistent objects, and
outlining the foremost problem an adequate theory of nonexistent objects must solve."
———. 1987. "On the Philosophical Foundations of Free Description Theory." History and Philosophy of Logic no. 8:57-66.
———, ed. 1991. Philosophical Applications of Free Logic. New York: Oxford University Press.
———. 1992. "Russell's Version of the Theory of Definite Descriptions." Philosophical Studies no. 65:153-167.
———. 1995. "Substitution and the Expansion of the World." Grazer Philosophische Studien no. 49:129-143.
"The major goal of this paper is to argue that a well known argument to overturn the principle that coextensive predicates substitute in any statement without alteration of truth
value can be avoided - even in the simplest of languages. Apparently this can be clone nonartificially only by expanding the universe with nonexisting objects. It is not proved that the principle of
substitution salva veritate holds in Meinongian model structures, but in fact it does - as any completeness proof of free logics based on inner domain-outer domain semantics will show. If -
as some have suggested - Meinong's views are compatible with the attitudes of a complete extensionalist, and he subscribed to the outlined modern theory of predication, there is no escape from
Aussersein. That may seem terribly obvious, but in the light of the development of free logics, more than mere conviction is needed. This dogmatic intuition is supplanted with some strong
———. 1997. Free Logics: Their Foundations, Character, and Some Applications Thereof. Sankt Augustin: Academia Verlag.
———. 2000. "Set Theory and Definite Descriptions. Four Solutions in Search of a Common Problem." Grazer Philosophische Studien no. 60:1-12.
———. 2003. Free Logic. Selected Essays. Cambridge: Cambridge University Press.
Lambert, Karel, and Fraassen, Bas C.van. 1972. Derivation and Counterexample. An Introduction to Philosophical Logic. Encino: Dickenson.
Lambert, Karel, and Ulrich, William. 1980. The Nature of Argument. New York: Macmillan.