In 1976, Michael Dummett delivered the William James Lectures at Harvard University. These lectures are usually published by Harvard University Press shortly after they are given, but professional commitments kept Dummett from making the necessary revisions until the late 1980’s, and the lectures were not published until 1991. The effects of the delay were not, however, entirely negative. It gave Dummett time to revise and expand the lectures so that the resulting book, The Logical Basis of Metaphysics, can fairly be seen as the definitive expression of his position on a number of the logical, semantic, and metaphysical issues that have been the focus of his career. Although the book may be the definitive statement of his views on these issues, Dummett does not regard it as providing a definitive solution to them. He says the book is merely his attempt to establish a base camp for future assaults on the metaphysical peaks still looming in the distance; he does not claim to take the expedition any further than the foothills of metaphysical truth.

The Logical Basis of Metaphysics begins with the observation that the nonprofessional expects philosophers to answer deep questions about the nature of the world. Such questions, concerning, for example, whether the will is free, whether the soul is immortal, or whether God exists, have traditionally been at the center of philosophical thinking. However, from the nonprofessional’s...

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Top-Down and Bottom-Up Strategies

Realists and antirealists have traditionally tackled these issues directly and then from their metaphysical positions derived conclusions about meaning and logic—an approach Dummett calls the “top-down” strategy. The debate between Platonists (the realists) and intuitionists (the antirealists) over the existence of mathematical objects and the objectivity of mathematical truth provides a clear example of this. Platonists hold the metaphysical view that there is a mind-independent world of mathematical structures. This metaphysical view is then invoked to justify the principles of classical logic including, in particular, the law of excluded middle: For any proposition P, either P or not-P is true. The belief that this logical principle is universally valid for mathematical statements is, then, based on the metaphysics of Platonism: Because there is an objective and fully determinate mathematical reality, it will determine that either P is true or not-P is true independently of whether it is possible to discover which of these is in fact the case. The traditional intuitionists also employ a top-down approach. Their basic metaphysical thesis is the idealist view that mathematical objects and truths are created by the construction of mathematical proofs and hence do not have a mind-independent existence. This leads them to deny the universal validity of the law of excluded middle: Because a mathematical statement is...

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The Truth-Conditional Theory and Verification

The most developed approach to meaning is the truth-conditional theory of meaning. According to this theory, the meaning of a sentence is its truth condition—the condition that must be satisfied in order for the sentence to be true. Therefore, understanding a sentence is a matter of grasping the condition that must be satisfied in order for it to be true. Truth, in this view, is in no way constrained by people’s capacity to discover it. This view endorses the principle of bivalence, which holds that sentences are determinately true or false independently of people’s capacity to discover their truth-value. The principle of bivalence supports classical logic: Because statements are true or false independently of one’s power to determine truth or falsity, the principles of classical logic, including the law of excluded middle, are the right ones. The metaphysical picture that emerges from the truth-conditional theory is realistic. Because statements are true or false independently of people’s access to the facts that determine their truth-value, people will find the picture of reality as mind-independent and fully determinate almost irresistible.

Although the truth-conditional theory of meaning is the most developed and widespread approach to meaning, Dummett believes that it fails to do what any adequate theory of meaning must do: provide an illuminating account of what it is for a speaker to understand the meaning of a sentence. The truth-conditional theory identifies what a speaker knows, but Dummett’s charge is that the theory cannot say what possession of such knowledge means by relating that knowledge to the speaker’s practical abilities. Because it is knowledge of truth conditions...

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Dummett and the Debate over Realism

Dummett devoted his career to articulating and exploring many of the themes of The Logical Basis of Metaphysics, so many of the ideas in this work exercised an influence long before the book itself was published. The aspect of Dummett’s work that has had the greatest impact is undoubtedly his analysis of the realism/antirealism dispute. More than anyone else, Dummett has redirected attention to this central philosophical issue, and his approach to it, the bottom-up strategy, dominates recent philosophical thinking on this topic. Even those philosophers dealing with the realism issue who do not accept the bottom-up approach to issues over realism feel compelled to explain why they reject it.

However, to acknowledge Dummett’s influence on contemporary philosophy is not, of course, to say that he has converted the philosophical world to antirealism or convinced it that the bottom-up approach is the proper way of doing metaphysical business. The position Dummett has staked out on the realism issue is controversial, so it is not surprising that he has had critics. Some have said, for example, that underlying the bottom-up strategy is nothing more than the positivist dogma that metaphysical theses are not resolvable by empirical means and so are meaningless. Others have argued that Dummett’s central argument against the truth-conditional theory of meaning presupposes epistemological behaviorism, at best a highly controversial view. Why, it is asked, must a speaker’s grasp of truth conditions be manifested in the observable behavior of recognizing that the condition is satisfied? Still other critics might bluntly suggest that any retreat from realism reveals not philosophical sophistication but a serious lack of a robust sense of reality. Even Dummett himself has sometimes expressed doubts about the coherence of global antirealism. However, in spite of these criticisms—and perhaps even because of them—the central ideas of The Logical Basis of Metaphysics have contributed enormously to the debate over realism.


Additional Reading

Devitt, Michael. Realism and Truth. Princeton, N.J.: Princeton University Press, 1991. An interpretation and assessment of most contemporary forms of antirealism from a naturalistic and physicalist standpoint. Devitt devotes a lengthy chapter to a detailed exposition and criticism of Michael Dummett’s antirealism.

French, P., T. Uehling, and H. Wettstein, eds. Realism and Antirealism. Vol. 12 in Midwest Studies in Philosophy. Minneapolis: University of Minnesota Press, 1988. A collection of papers exploring many aspects of the realism/antirealism debate. Many of the papers discuss issues raised by Dummett’s treatment of realism and antirealism.

Heck, Richard G., ed. Language, Thought, and Logic: Essays in Honour of Michael Dummett. Oxford: Oxford University Press, 1997. Many of the papers in this collection focus on Dummett’s contributions to the philosophy of language, especially issues concerning the relationship between thought and language. Others concern Dummett’s views on the nature of time, Gottlob Frege, and the philosophy of mathematics.

Luntley, Michael. Language, Logic, and Experience. La Salle, Ill.: Open Court, 1988. Building on Dummett, the author articulates and defends an antirealist account of logic, truth, and reality. For advanced undergraduates.

McGuinness, B., and G. Oliveri, eds. The Philosophy of Michael Dummett. Dordrecht, Netherlands: Kluwer Academic, 1994. This collection contains papers on Dummett’s philosophies of language, mathematics, time, mind, and religion. Also includes Dummett’s replies to his critics.

Taylor, Barry, ed. Michael Dummett: Contributions to Philosophy. Dordrecht, Netherlands: Martinus Nijhoff, 1987. Although most of the essays in this collection focus on Dummett’s antirealism, the book also includes papers on two of his nonphilosophical passions: the history of playing cards and card games and the struggle for racial justice and equality in Britain. Also contains Dummett’s responses.

Wright, Crispin. Realism, Meaning, and Truth. Oxford: Basil Blackwell, 1987. A collection of Wright’s papers on Dummett and topics relating to antirealism. Wright’s introductory essay is especially valuable for beginning students of the realism/antirealism debate.

Wright, Crispin. Wittgenstein on the Foundations of Mathematics. London: Gerald Duckworth, 1980. While the nominal subject of the book is Ludwig Wittgenstein’s philosophy of mathematics, many of Dummett’s central ideas are explored. A difficult book but worth the effort.

Young, James O. Global Anti-realism. Aldershot, England: Avebury, 1995. A brief and readable defense of antirealism. Recommended for undergraduates interested in realism and antirealism.