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11Review: Richard E. Grandy, Advanced Logic for Applications (review)Journal of Symbolic Logic 47 (3): 714-716. 1982.
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156Deflationism and the gödel phenomena: Reply to KetlandMind 114 (453): 89-96. 2005.I am not a deflationist. I believe that truth and falsity are substantial. The truth of a proposition consists in its having a constructive proof, or truthmaker. The falsity of a proposition consists in its having a constructive disproof, or falsitymaker. Such proofs and disproofs will need to be given modulo acceptable premisses. The choice of these premisses will depend on the discourse in question.
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41Conventional Necessity and the Contingency of ConventionDialectica 41 (1‐2): 79-95. 1987.SummaryI defend a conventionalist view of logical and mathematical truths against the criticisms of Quine and Stroud. Conventionalism is best formulated by appealing to sense‐conferring rules governing important logical and mathematical expressions. Conventional necessity can be understood as arising from these rules in a way that is immune to Quine's and Stroud's criticisms of the earlier formulation of conventionalism, in which stress was incorrectly laid on axiomatic systems of logic.RésuméJe…Read more
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40Williamson’s WoesSynthese 173 (1): 9-23. 2010.This is a reply to Timothy Williamson ’s paper ‘Tennant’s Troubles’. It defends against Williamson ’s objections the anti-realist’s knowability principle based on the author’s ‘local’ restriction strategy involving Cartesian propositions, set out in The Taming of the True. Williamson ’s purported Fitchian reductio, involving the unknown number of books on his table, is analyzed in detail and shown to be fallacious. Williamson ’s attempt to cause problems for the anti-realist by means of a suppos…Read more
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87Intuitionistic mathematics does not needex falso quodlibetTopoi 13 (2): 127-133. 1994.We define a system IR of first-order intuitionistic relevant logic. We show that intuitionistic mathematics (on the assumption that it is consistent) can be relevantized, by virtue of the following metatheorem: any intuitionistic proof of A from a setX of premisses can be converted into a proof in IR of eitherA or absurdity from some subset ofX. Thus IR establishes the same inconsistencies and theorems as intuitionistic logic, and allows one to prove every intuitionistic consequence of any consi…Read more
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111Belief-revision, the Ramsey test, monotonicity, and the so-called impossibility resultsReview of Symbolic Logic 1 (4): 402-423. 2008.Peter G¨ ardenfors proved a theorem purporting to show that it is impossible to adjoin to the AGM -postulates for belief-revision a principle of monotonicity for revisions. The principle of monotonicity in question is implied by the Ramsey test for conditionals. So G¨
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60Ultimate Normal Forms for Parallelized Natural DeductionsLogic Journal of the IGPL 10 (3): 299-337. 2002.The system of natural deduction that originated with Gentzen , and for which Prawitz proved a normalization theorem, is re-cast so that all elimination rules are in parallel form. This enables one to prove a very exigent normalization theorem. The normal forms that it provides have all disjunction-eliminations as low as possible, and have no major premisses for eliminations standing as conclusions of any rules. Normal natural deductions are isomorphic to cut-free, weakening-free sequent proofs. …Read more
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69The Law of Excluded Middle Is Synthetic A Priori, If ValidPhilosophical Topics 24 (1): 205-229. 1996.
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27Evolutionary v. Evolved EthicsPhilosophy 58 (225): 289-302. 1983.Kant writes: If … the only aim of Nature regarding some creature possessed of reason and a will were its preservation, its well-being, in a word its happiness, then she would have come to a very bad arrangement in choosing its reason as executor of that aim. For all actions that it had to execute in this her intention, and the whole regulation of its behaviour would have been able to be prescribed to it much more precisely by instinct, and that aim thereby much more certainly maintained, than ev…Read more
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51New Foundations for a Relational Theory of Theory-revisionJournal of Philosophical Logic 35 (5): 489-528. 2006.AGM-theory, named after its founders Carlos Alchourrón, Peter Gärdenfors and David Makinson, is the leading contemporary paradigm in the theory of belief-revision. The theory is reformulated here so as to deal with the central relational notions 'J is a contraction of K with respect to A' and 'J is a revision of K with respect to A'. The new theory is based on a principal-case analysis of the domains of definition of the three main kinds of theory-change (expansion, contraction and revision). Th…Read more
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BOSTOCK, D. "Logic and Arithmetic, Vol. II-Rational and Irrational Numbers" (review)Mind 90 (n/a): 473. 1981.
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49Sex and the evolution of fair-dealingPhilosophy of Science 66 (3): 391-414. 1999.Brian Skyrms has studied the evolutionary dynamics of a simple bargaining game. Fair-dealing is the strategy 'demand 1/2', competing with the more modest strategy 'demand 1/3' and the greedier strategy 'demand 2/3'. Individuals leave offspring in proportion to their accumulated payoffs. The rules for payoffs from encounters penalize low- and high-demanders. The result is a significant basin of attraction for fair-dealing as an evolutionarily stable strategy. From these considerations Skyrms conc…Read more
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1Delicate proof theoryIn Brian Jack Copeland (ed.), Logic and reality: essays on the legacy of Arthur Prior, Oxford University Press. pp. 351--385. 1996.
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294Anti-realism and logic: truth as eternalOxford University Press. 1987.Anti-realism is a doctrine about logic, language, and meaning that is based on the work of Wittgenstein and Frege. In this book, Professor Tennant clarifies and develops Dummett's arguments for anti-realism and ultimately advocates a radical reform of our logical practices.
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298Changing the theory of theory change: Towards a computational approachBritish Journal for the Philosophy of Science 45 (3): 865-897. 1994.The Theory of theory change has contraction and revision as its central notions. Of these, contraction is the more fundamental. The best-known theory, due to Alchourrón, Gärdenfors, and Makinson, is based on a few central postulates. The most fundamental of these is the principle of recovery: if one contracts a theory with respect to a sentence, and then adds that sentence back again, one recovers the whole theory. Recovery is demonstrably false. This paper shows why, and investigates how one ca…Read more
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2Intentionality, syntactic structure and the evolution of languageIn Christopher Hookway (ed.), Minds, Machines And Evolution, Cambridge University Press. 1984.
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38On the Degeneracy of the Full AGM-Theory of Theory-RevisionJournal of Symbolic Logic 71 (2). 2006.A general method is provided whereby bizarre revisions of consistent theories with respect to contingent sentences that they refute can be delivered by revision-functions satisfying both the basic and the supplementary postulates of the AGM-theory of theory-revision
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97Rule-Circularity and the Justification of DeductionPhilosophical Quarterly 55 (221). 2005.I examine Paul Boghossian's recent attempt to argue for scepticism about logical rules. I argue that certain rule- and proof-theoretic considerations can avert such scepticism. Boghossian's 'Tonk Argument' seeks to justify the rule of tonk-introduction by using the rule itself. The argument is subjected here to more detailed proof-theoretic scrutiny than Boghossian undertook. Its sole axiom, the so-called Meaning Postulate for tonk, is shown to be false or devoid of content. It is also shown tha…Read more
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218Carnap, gödel, and the analyticity of arithmeticPhilosophia Mathematica 16 (1): 100-112. 2008.Michael Friedman maintains that Carnap did not fully appreciate the impact of Gödel's first incompleteness theorem on the prospect for a purely syntactic definition of analyticity that would render arithmetic analytically true. This paper argues against this claim. It also challenges a common presumption on the part of defenders of Carnap, in their diagnosis of the force of Gödel's own critique of Carnap in his Gibbs Lecture. The author is grateful to Michael Friedman for valuable comments. Part…Read more
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71Is every truth knowable? Reply to WilliamsonRatio 14 (3). 2001.This paper addresses an objection raised by Timothy Williamson to the ‘restriction strategy’ that I proposed, in The Taming of The True, in order to deal with the Fitch paradox. Williamson provides a new version of a Fitch-style argument that purports to show that even the restricted principle of knowability suffers the same fate as the unrestricted one. I show here that the new argument is fallacious. The source of the fallacy is a misunderstanding of the condition used in stating the restricte…Read more
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41The Taming of the TruePhilosophical Review 109 (2): 290. 2000.The Taming of the True continues the project Neil Tennant began in Anti-realism and Logic of investigating and defending anti-realism. Tennant’s earlier book anticipated a second volume, in which issues related to empirical discourse would be addressed in greater detail. The Taming of the True provides this sequel. It also attempts a ground-clearing project, by addressing challenges to some of the presuppositions and implications of Tennant’s anti-realist position. Finally, it takes an opportuni…Read more
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156On the necessary existence of numbersNoûs 31 (3): 307-336. 1997.We examine the arguments on both sides of the recent debate (Hale and Wright v. Field) on the existence, and modal status, of the natural numbers. We formulate precisely, with proper attention to denotational commitments, the analytic conditionals that link talk of numbers with talk of numerosity and with counting. These provide conceptual controls on the concept of number. We argue, against Field, that there is a serious disanalogy between the existence of God and the existence of numbers. We g…Read more
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