6 minute read

Truth

Deflationary Theories

Deflationary theories treat the truth predicate as having only a logical or grammatical function, rather than as ascribing a property or relation to a truth bearer, as on correspondence, pragmatist, and coherence theories. Frank Plumpton Ramsey (1903–1930) proposed, contrary to Moore, that true generally makes no substantive contribution to what is asserted in a statement: "'it is true that Caesar was murdered' means no more than that Caesar was murdered" (p. 157). "Whatever he says is true" comes out "For all p, if he says that p, then p." This is called the redundancy theory of truth. It is deflationary in denying that true expresses a property of truth bearers or a relation of correspondence between truth bearers and the way the world is.

In Philosophical Investigations (1958), Ludwig Wittgenstein (1889–1951) rejected his idea presented in the Tractatus (1961, originally published in 1922) that "This is how things are" expresses the general form of a proposition. This form of words does express a proposition, but "To say that this proposition agrees or does not agree with reality would be obvious nonsense." Rather, it is a propositional variable the value of which is fixed by an earlier statement, in the way the referent of a pronoun is fixed by an earlier use of a name. This proposal, known as the "prosentential" theory of truth because it treats "That is true" as a "prosentence," was subsequently developed by Dorothy Grover, Joseph L. Camp, Jr., and Nuel D. Belnap, Jr. (1975).

Willard Van Orman Quine (1908–2000) proposed that the truth predicate is used for semantic ascent, which in certain cases is indispensable for expressive purposes: "If we want to affirm some infinite lot of sentences that we can demarcate only by talking about sentences, then the truth predicate has its use" (p. 11). If we wish to say only that Tom is mortal, we can say "'Tom is mortal' is true," but we need not do so. But if we wish to affirm each of the sentences of Euclidean geometry, we have no option but to say "All the sentences of Euclidean geometry are true." We are saying no more than we would say by uttering each of the sentences, but since there are infinitely many of them, we cannot utter them all. For this reason, the truth predicate is practically indispensable. This suggests a disquotational theory of truth on which the content of true for a language is given by all the equivalences: "p" is true just in case p (for all sentences "p" of the language). Presumably, occurrences of true in contexts like "What he said is true" or "That is true" would be either spelled out in the manner of Ramsey or implicitly defined by the T-equivalences in virtue of the fact that the subject of the sentence refers to a particular sentence. Paul Horwich developed a related minimalist theory of truth by taking as the axioms of the theory all the equivalences: the proposition that p is true if and only if p (1990). These deflationary theories have, in common with Moore's and Russell's correspondence theories, the disadvantage of entailing the principle of bivalence, which prohibits "truth-value gaps," as in borderline vague sentences or sentences with presuppositions that fail. A correspondence theory such as Field's can be formulated in a way that avoids bivalence (1972). Deflationary theories also differ from correspondence theories in making it impossible to ascribe truth to sentences in a language we can't understand. Field argued in a 1986 article that a deflationary notion of truth cannot be employed to account for how our tendency to believe truths explains our practical success in action.

Some have denied that truth is definable. Gottlob Frege (1848–1925) argued that if truth is definable as a property, then any judgment of whether an idea is true would involve judging whether the idea has the property, and the question would then arise whether it is true that the idea has the property, generating a circle (1956). The early Moore (1953, p. 262) and Donald Davidson (1917–2003) also denied that truth is definable. Since 1980, philosophers (e.g., Huw Price) have shown an interest in functionalist accounts of truth, which characterize truth in terms of its cognitive or social function, rather than define the concept in other terms.

BIBLIOGRAPHY

Aquinas, St. Thomas. Summa Theologiae. 2 vols. Edited by Thomas Gilby. Garden City, N.Y.: Image Books, 1969.

Aristotle. The Complete Works of Aristotle: The Revised Oxford Translation. 2 vols. Edited by Jonathan Barnes. Princeton, N.J.: Princeton University Press, 1984.

Austin, J. L. "Truth." Proceedings of the Aristotelian Society 24 (1950): 111–128.

Blanshard, Brand. The Nature of Thought. 2 vols. New York: Allen and Unwin, 1939.

Bradley, F. H. Essays on Truth and Reality. Oxford: Clarendon, 1914.

Davidson, Donald. "The Folly of Trying to Define Truth." Journal of Philosophy 93 (1996): 263–278.

Descartes, René. "Letter to Marin Mersenne, 16 October 1639." In Descartes: Philosophical Letters. Translated and edited by Anthony Kenny. Minneapolis: University of Minnestoa Press, 1970.

Field, Hartry. "The Deflationary Conception of Truth." In Fact, Science, and Morality: Essays on A. J. Ayer's Language, Truth, and Logic, edited by Graham Macdonald and Crispin Wright. Oxford: Blackwell, 1986.

——. "Tarski's Theory of Truth." Journal of Philosophy 69 (1972): 347–375.

Frege, Gottlob. "The Thought: A Logical Inquiry." Translated by A. M. Quinton and Marcelle Quinton. Mind 65 (1956): 289–311.

Grover, Dorothy, Joseph L. Camp, Jr., and Nuel D. Belnap, Jr. "A Prosentential Theory of Truth." Philosophical Studies 27 (1975): 73–125.

Hegel, Georg Wilhelm Friedrich. Hegel's Science of Logic. Translated by A. V. Miller. Atlantic Highlands, N.J.: Humanities Press, 1989.

Horwich, Paul. Truth. Oxford: Blackwell, 1990.

Hume, David. A Treatise of Human Nature. 2nd ed., edited by L. A. Selby-Bigge. Oxford: Clarendon, 1978.

James, William. Pragmatism: A New Name for Some Old Ways of Thinking, Together with Four Related Essays Selected from The Meaning of Truth. New York: Longmans, Green, and Co., 1947.

Joachim, Harold H. The Nature of Truth. Oxford: Clarendon, 1906.

Kant, Immanuel. Critique of Pure Reason. Translated and edited by Paul Guyer and Allen W. Wood. Cambridge, U.K.: Cambridge University Press, 1997.

——. Logic. Translated by Robert S. Hartman and Wolfgang Schwarz. Indianapolis: Bobbs-Merrill, 1974.

Locke, John. An Essay Concerning Human Understanding. 2 vols. Edited by A. C. Fraser. New York: Dover Publications, 1959.

Moore, G. E. Some Main Problems of Philosophy. London: Allen and Unwin, 1953.

Peirce, Charles Sanders. The Essential Peirce: Selected Philosophical Writings. 2 vols. Edited by Nathan Houser and Christian Kloesel. Bloomington: Indiana University Press, 1992–1998.

Plato. The Collected Dialogues of Plato. Edited by Edith Hamilton and Huntington Cairns. New York: Pantheon, 1961.

Price, Huw. Facts and the Function of Truth. Oxford: Blackwell, 1988.

Quine, W. V. Philosophy of Logic. Englewood Cliffs, N.J.: Prentice-Hall, 1970.

Ramsey, Frank P. "Facts and Propositions." Proceedings of the Aristotelian Society 7 (1927): 153–170.

Russell, Bertrand. An Inquiry into Meaning and Truth. London: Allen and Unwin, 1921.

——. Logic and Knowledge, Essays 1901–1950. Edited by R. C. Marsh. London: Allen and Unwin, 1956.

——. "On the Nature of Truth." Proceedings of the Aristotelian Society 7 (1906–1907): 28–49.

——. The Problems of Philosophy. New York: H. Holt, 1912.

Sextus Empiricus. Against the Professors 8.85–6. In The Hellenistic Philosophers. 2 vols. Edited and translated by A. A. Long and D. N. Sedley. Cambridge, U.K.: Cambridge University Press, 1987.

Spinoza, Baruch. Ethics. In The Collected Works of Spinoza, volume 1. Translated and edited by Edwin Curley. Princeton, N.J.: Princeton University Press, 1985.

Strawson, P. F. "Truth." Proceedings of the Aristotelian Society 24 (1950): 129–156.

Tarski, Alfred. "The Semantic Conception of Truth and the Foundations of Semantics." Philosophy and Phenomenological Research 4 (1944): 341–375.

Wittgenstein, Ludwig. Philosophical Investigations. Translated by G. E. M. Anscombe. New York: Macmillan, 1953.

——. Tractatus Logico-Philosophicus. Translated by D. F. Pears and B. F. McGuiness. London: Routledge and Paul, 1961.

Frederick F. Schmitt

Additional topics

Science EncyclopediaScience & Philosophy: Toxicology - Toxicology In Practice to TwinsTruth - The Correspondence Theory: Ancient And Modern, Pragmatist And Coherence Theories, The Correspondence Theory: Twentieth Century