Stephen Read

Intentional verbs create three different problems: problems of non-existence, of indeterminacy, and of failure of substitutivity. Meinongians tackle the first problem by recognizing non-existent objects; so too did many medieval logicians. Meinongians and the medievals approach the problem of indeterminacy differently, the former diagnosing an ellipsis for a propositional complement, the latter applying their theory directly to non-propositional complements. The evidence seems to favour the Meinongian approach. Faced with the third problem, Ockham argued bluntly for substitutivity when the intentional complement is non-propositional; Buridan developed a novel way of resisting substitutivity. Ockham's approach is closer to the Meinongian analysis of these cases; Buridan's seems to raise difficulties for a referential semantics. The comparision between the Meinongian and medieval approaches helps to bring out merits and potential pitfalls of each.

Stephen Read - Johannes Buridanus: Summulae de Practica Sophismatum - Journal of the History of Philosophy 45:1 Journal of the History of Philosophy 45.1 157-158 Muse Search Journals This Journal Contents Reviewed by Stephen Read University of St. Andrews Fabienne Pironet, editor. Johannes Buridanus: Summulae de Practica Sophismatum. Artistarium 10–9. Turnhout: Brepols 2004. Pp. xlix + 193. Paper, €40.00. John Buridan was an unusual figure in fourteenth-century logic and philosophy. Logic was at that time largely the preserve of the young, who would lecture on logic while studying in higher faculties such as theology, before moving on to lecture in their maturity on philosophy and theology. Two notable exceptions are the Englishman Walter Burley and the Frenchman from Picardy, John Buridan. Already active in the Arts Faculty at Paris in the late 1320s, Buridan was still there thirty years later. In the meantime, among other works on metaphysics, ethics, politics, and natural philosophy, he..

In this book, Stephen Read sets out to rescue logic from its undeserved reputation as an inflexible, dogmatic discipline by demonstrating that its technicalities and processes are founded on assumptions which are themselves amenable to philosophical investigation. He examines the fundamental principles of consequence, logical truth and correct inference within the context of logic, and shows that the principles by which we delineate consequences are themselves not guaranteed free from error. Central to the notion of truth is the beguiling issue of paradox. Its philosophical value, Read shows, lies in exposing the invalid assumption on which the paradox is built. Thinking About Logic also discusses logical puzzles which introduce questions relating to language, the world, and their relationship.

Bradwardine’s solution to the the logical paradoxes depends on the idea that every sentence signifies many things, and its truth depends on things’ being wholly as it signifies. This idea is underpinned by his claim that a sentence signifies everything that follows from what it signifies. But the idea that signification is closed under entailment appears too strong, just as logical omniscience is unacceptable in the logic of knowledge. What is needed is a more restricted closure principle. A clue can be found in speech act pluralism, whereby indirect speech reports are closed under intersubstitutivity of co-referential terms. The conclusion is that solving the semantic paradoxes does not require revision of logic, thus saving logic from paradox

Thomas Bradwardine's solution to the semantic paradoxes, presented in his Insolubilia written in Oxford in the early 1320s, turns on two main principles: that a proposition is true only if things are wholly as it signifies; and that signification is closed under consequence. After exploring the background in Walter Burley's account of the signification of propositions, the question is considered of the extent to which Bradwardine's theory is compatible with the distribution of truth over conjunction, disjunction, negation and the conditional.

General-elimination harmony articulates Gentzen’s idea that the elimination-rules are justified if they infer from an assertion no more than can already be inferred from the grounds for making it. Dummett described the rules as not only harmonious but stable if the E-rules allow one to infer no more and no less than the I-rules justify. Pfenning and Davies call the rules locally complete if the E-rules are strong enough to allow one to infer the original judgement. A method is given of generating harmonious general-elimination rules from a collection of I-rules. We show that the general-elimination rules satisfy Pfenning and Davies’ test for local completeness, but question whether that is enough to show that they are stable. Alternative conditions for stability are considered, including equivalence between the introduction- and elimination-meanings of a connective, and recovery of the grounds for assertion, finally generalizing the notion of local completeness to capture Dummett’s notion of stability satisfactorily. We show that the general-elimination rules meet the last of these conditions, and so are indeed not only harmonious but also stable.

This chapter focuses on alternative logics. It discusses a hierarchy of logical reform. It presents case studies that illustrate particular aspects of the logical revisionism discussed in the chapter. The first case study is of intuitionistic logic. The second case study turns to quantum logic, a system proposed on empirical grounds as a resolution of the antinomies of quantum mechanics. The third case study is concerned with systems of relevance logic, which have been the subject of an especially detailed reform program. Finally, the fourth case study is paraconsistent logic, perhaps the most controversial of serious proposals.

This book presents the very latest research on the medieval use of sophisms in logical and grammatical investigation by twenty-three of the leading experts in Europe and beyond. Important insights into the genre of sophismatic treatises have been gained only very recently, and the organisation of the European Symposium on this topic in 1990 led to a concentration of research and evaluation of insights. The papers are divided into three groups: one covers textual study and analysis of the role of sophisms in the medieval curriculum; another deals with grammatical sophisms; and the third covers particular logical sophisms, from 'Man is the worthiest of creatures' and problems in the theory of reference to the Liar paradox and the work of William of Ockham.

MEDIEVAL AND RENAISSANCE LOGICSIMON OF FAVERSHAM, Quaestiones super Libro Elenchorum. Text in Latin with introduction and notes in English, edited by Sten Ebbesen, Thomas Izbicki, John Longeway, Francesco del Punta, Eileen Serene and Eleonore Stump. Toronto: Pontifical Institute of Mediaeval Studies, 1984. xiv + 270 pp. $3 1.OO.JACOPO ZABARELLA, De methodis libri quatuor; Liber de regressu. Edited by Cesare Vasoli. Bologna: Editrice CLUEB, 1985. xxxviii+ 193 pp. Lire 57,000.EDITIONSG. W. F. HEGEL, Wissenschafl der Logik. Erster Teil. Die objektive Logik, Erster Band. Die Lehre von Sein. Herausgegeben von F. Hogemann und W. Jaeschke. Hamburg: Felix Meiner Verlag, 1985. x + 448 S. DM 140.BERNARD BOLZANO, Wissenschaftslehre, Sects. 1-45. Edited and introduction Jan Berg. Stuttgart-Bad Cannstatt: Friedrich Fromman, 1985. 269 pp. No price stated.MAX H. FISCH, C. J. W. KLOESEL, E. C. MOORE and DON D.ROBERTS, LYNN A. ZIEGLER, Writings of Charles S. Peirce: a chronological edition. Bloomington, Indiana: Indiana University Press. Vol. I 1857-1866. 1982. xxxv + 698 pp. $32.50. Vo l. I1 1867-1871. 1984. xlviii + 649 pp. with introductory essays by Max H. Fisch, C. F. Delaney and Daniel D. -Merrill. $35.00.ALFRED TARSKI, Logic, semantics, metamathematics. Translated by J. H. Woodger. Second edition, edited and introduced by John Corcoran. Philadelphia: Hackett, 1983, xxx+ 506 pp. $50.00/£37.50 ; $29.50/&27.50.J. MITTELSTRASS, Enzyklopadie Philosophie und Wissenschaftstheorie, Bd.2: H-0. Mannheim, Wien, Zurich: Bibliographisches Institut, 1984. 1105 pp. DM 156.LOGIC AND MATHEMATICSA. GROTE, Anzahl, Zahl und Menge. Die phanomenologische Grundlagen der Arithmetik. Hamburg: Meiner, 1983. vii + 143 pp. DM 36.VICTOR LOWE, Alfred North Whitehead: the man and his work. Volume 1: 1861-1910. Baltimore and London: The Johns Hopkins University Press, 1985. xi+ 351 pp. $27.50/£26.40.MURIEL SELTMAN and PETER SELTMAN, Piaget's logic: a critique of genetic epistemology. London, Boston and Sydney: George Allen and Unwin, 1985. ix+ 353 pp. £30.00.MORRIS KLINE, Mathemafics: the loss of certainty. New York: Oxford University Press, 1980. vi + 366 pp. $19.95.RACHEL WALLACE GARDEN, Modern logic and quantum mechanics. Bristol: Adam Hilger, 1983. xii+ 178 pp. £18.00.LOGIC AND LANGUAGEH. LEBLANC, E. MENDELSON and A. ORESTEIN, Logic, language, and mathematics. Dordrecht and Boston: D. Reidel Publishing Company, 1984, 282 pp. Dfl.90/$34.50.R. M. MARTIN, Mind, modality, meaning and method. Albany, New York: State University of New York Press, 1983. xiv+ 225 pp. $44.50 /$16.95.HERBERT HOCHBERG, Logic, ontology, and language-essays on truth and reality. Miinchen and Wein: Philosophia Verlag, 1984. 448 pp., $74.00.

In recent years, speech-act theory has mooted the possibility that one utterance can signify a number of different things. This pluralist conception of signification lies at the heart of Thomas Bradwardine’s solution to the insolubles, logical puzzles such as the semantic paradoxes, presented in Oxford in the early 1320s. His leading assumption was that signification is closed under consequence, that is, that a proposition signifies everything which follows from what it signifies. Then any proposition signifying its own falsity, he showed, also signifies its own truth and so, since it signifies things which cannot both obtain, it is simply false. Bradwardine himself, and his contemporaries, did not elaborate this pluralist theory, or say much in its defence. It can be shown to accord closely, however, with the prevailing conception of logical consequence in England in the fourteenth century. Recent pluralist theories of signification, such as Grice’s, also endorse Bradwardine’s closure postulate as a plausible constraint on signification, and so his analysis of the semantic paradoxes is seen to be both well-grounded and plausible.

Michael Dummett and Dag Prawitz have argued that a constructivist theory of meaning depends on explicating the meaning of logical constants in terms of the theory of valid inference, imposing a constraint of harmony on acceptable connectives. They argue further that classical logic, in particular, classical negation, breaks these constraints, so that classical negation, if a cogent notion at all, has a meaning going beyond what can be exhibited in its inferential use. I argue that Dummett gives a mistaken elaboration of the notion of harmony, an idea stemming from a remark of Gerhard Gentzen's. The introduction-rules are autonomous if they are taken fully to specify the meaning of the logical constants, and the rules are harmonious if the elimination-rule draws its conclusion from just the grounds stated in the introduction-rule. The key to harmony in classical logic then lies in strengthening the theory of the conditional so that the positive logic contains the full classical theory of the conditional. This is achieved by allowing parametric formulae in the natural deduction proofs, a form of multiple-conclusion logic

The correspondence theory of truth has experienced something of a revival recently in the form of the Truthmaker Axiom: whatever is true, something makes it true. We consider various postulates which have been proposed to characterize truthmaking, in particular, the Disjunction Thesis (DT), that whatever makes a disjunction true must make one or other disjunct true. In conjunction with certain other assumptions, DT leads to triviality. We show that there are elaborations of truthmaking on which DT holds (which must therefore take steps to avoid the triviality); but that there are more plausible accounts of truthmaking on which DT fails.