Problems on Philosophical Logic
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In Defence of Folk Psychology
FRANK JACKSON & PHILIP PETTIT IN DEFENCE OF FOLK PSYCHOLOGY (Received 14 October, 1988) It turned out that there was no phlogiston, no caloric fluid, and no luminiferous ether. Might it turn out that there are no beliefs and desires? Patricia and Paul Churchland say yes. ~ We say no. In part one we give our positive argument for the existence of beliefs and desires, and in part two we offer a diagnosis of what has misled the Church- lands into holding that it might very well turn out that there are no beliefs and desires. 1. THE EXISTENCE OF BELIEFS AND DESIRES 1.1. Our Strategy Eliminativists do not insist that it is certain as of now that there are no beliefs and desires. They insist that it might very well turn out that there are no beliefs and desires. Thus, in order to engage with their position, we need to provide a case for beliefs and desires which, in addition to being a strong one given what we now know, is one which is peculiarly unlikely to be undermined by future progress in neuroscience. Our first step towards providing such a case is to observe that the question of the existence of beliefs and desires as conceived in folk psychology can be divided into two questions. There exist beliefs and desires if there exist creatures with states truly describable as states of believing that such-and-such or desiring that so-and-so. Our question, then, can be divided into two questions. First, what is it for a state to be truly describable as a belief or as a desire; what, that is, needs to be the case according to our folk conception of belief and desire for a state to be a belief or a desire? And, second, is what needs to be the case in fact the case? Accordingly , if we accepted a certain, simple behaviourist account of, say, our folk Philosophical Studies 59:31--54, 1990. -
John P. Burgess Department of Philosophy Princeton University Princeton, NJ 08544-1006, USA [email protected]
John P. Burgess Department of Philosophy Princeton University Princeton, NJ 08544-1006, USA [email protected] LOGIC & PHILOSOPHICAL METHODOLOGY Introduction For present purposes “logic” will be understood to mean the subject whose development is described in Kneale & Kneale [1961] and of which a concise history is given in Scholz [1961]. As the terminological discussion at the beginning of the latter reference makes clear, this subject has at different times been known by different names, “analytics” and “organon” and “dialectic”, while inversely the name “logic” has at different times been applied much more broadly and loosely than it will be here. At certain times and in certain places — perhaps especially in Germany from the days of Kant through the days of Hegel — the label has come to be used so very broadly and loosely as to threaten to take in nearly the whole of metaphysics and epistemology. Logic in our sense has often been distinguished from “logic” in other, sometimes unmanageably broad and loose, senses by adding the adjectives “formal” or “deductive”. The scope of the art and science of logic, once one gets beyond elementary logic of the kind covered in introductory textbooks, is indicated by two other standard references, the Handbooks of mathematical and philosophical logic, Barwise [1977] and Gabbay & Guenthner [1983-89], though the latter includes also parts that are identified as applications of logic rather than logic proper. The term “philosophical logic” as currently used, for instance, in the Journal of Philosophical Logic, is a near-synonym for “nonclassical logic”. There is an older use of the term as a near-synonym for “philosophy of language”. -
Deontic Logic and Meta-Ethics
Deontic Logic and Meta-Ethics • Deontic Logic as been a field in which quite apart from the questions of antinomies "paradoxes" have played a decisive roles, since the field has been invented. These paradoxes (like Ross' Paradox or the Good Samaritian) are said to show that some intuitively valid logical principles cannot be true in deontic logic, even if the same principles (like deductive closure within a modality) are valid in alethic modal logic. Paraconsistency is not concerned with solutions to these paradoxes. pp ∧¬∧¬pp • There are, however, lots of problems with ex contradictione qoudlibet Manuel Bremer in deontic logic, since systems of norms and regulations, even more so Centre for Logic, Language and if they are historically grown, have a tendency to contain conflicting Information requirements. To restrict the ensuing problems at least a weak paraconsistent logic is needed. • There may be, further on, real antinomies of deontic logic and meta- ethics (understood comprehensively as including also some basic decision and game theory). Inconsistent Obligations • It often may happen that one is confronted with inconsistent obligations. • Consider for example the rule that term papers have to be handed in at the institute's office one week before the session in question combined with the rule that one must not disturb the secretary at the institute's office if she is preparing an institute meeting. What if the date of handing in your paper falls on a day when an institute meeting is pp ∧¬∧¬pp prepared? Entering the office is now obligatory (i.e. it is obligatory that it is the Manuel Bremer case that N.N. -
Concrete Possible Worlds (Final)
CONCRETE POSSIBLE WORLDS Phillip Bricker 1. INTRODUCTION. Open a book or article of contemporary analytic philosophy, and you are likely to find talk of possible worlds therein. This applies not only to analytic metaphysics, but to areas as diverse as philosophy of language, philosophy of science, epistemology, and ethics. Philosophers agree, for the most part, that possible worlds talk is extremely useful for explicating concepts and formulating theories. They disagree, however, over its proper interpretation. In this chapter, I discuss the view, championed by David Lewis, that philosophers’ talk of possible worlds is the literal truth.1 There exists a plurality of worlds. One of these is our world, the actual world, the physical universe that contains us and all our surroundings. The others are merely possible worlds containing merely possible beings, such as flying pigs and talking donkeys. But the other worlds are no less real or concrete for being merely possible. Fantastic? Yes! What could motivate a philosopher to believe such a tale? I start, as is customary, with modality.2 Truths about the world divide into two sorts: categorical and modal. Categorical truths describe how things are, what is actually the case. Modal truths describe how things could or must be, what is possibly or 1 The fullest statement of Lewis’s theory of possible worlds is contained in his magnum opus, Lewis (1986), On the Plurality of Worlds. Lewis’s view is sometimes called “modal realism.” 2 Historically, it was the attempt to provide semantics for modal logic that catapulted possible worlds to the forefront of analytic philosophy. -
David Lewis's Place in Analytic Philosophy Scott Soames by The
David Lewis’s Place in Analytic Philosophy Scott Soames By the early 1970s, and continuing through 2001, David Lewis and Saul Kripke had taken over W.V.O. Quine’s leadership in metaphysics, epistemology, philosophy of language, and philosophical logic in the English-speaking world. Quine, in turn, had inherited his position in the early 1950s from Rudolf Carnap, who had been the leading logical positivist -- first in Europe, and, after 1935, in America. A renegade positivist himself, Quine eschewed apriority, necessity, and analyticity, while (for a time) adopting a holistic version of verificationism. Like Carnap, he placed philosophical logic and the philosophy of science at the center of philosophy. While not entirely avoiding metaphysics and epistemology, he tried to “naturalize” both. By contrast, Lewis and Kripke embraced the modalities Quine rejected.1 They also had no sympathy for his early verificationism, or his twin flights from intension and intention. As for philosophy of science, it was transforming itself into specialized philosophies of the several sciences, and did not lend itself to unified treatment. Although Lewis had deep interests in scientific issues, and was commendably realist about science in general, science itself was not the center of own distinctive approach to philosophy. Despite similarities in their opposition to Quine, the differences between Lewis and Kripke were large – especially in the semantics and metaphysics of modality. They also had different philosophical styles. Whereas Lewis was a wide-ranging thinker who pieced together a systematic philosophical world view, Kripke gave little thought to system, focusing instead on a few central topics. There is, therefore, no conflict between the two on many of the issues on which Kripke was silent. -
Logic: a Brief Introduction Ronald L
Logic: A Brief Introduction Ronald L. Hall, Stetson University Chapter 1 - Basic Training 1.1 Introduction In this logic course, we are going to be relying on some “mental muscles” that may need some toning up. But don‟t worry, we recognize that it may take some time to get these muscles strengthened; so we are going to take it slow before we get up and start running. Are you ready? Well, let‟s begin our basic training with some preliminary conceptual stretching. Certainly all of us recognize that activities like riding a bicycle, balancing a checkbook, or playing chess are acquired skills. Further, we know that in order to acquire these skills, training and study are important, but practice is essential. It is also commonplace to acknowledge that these acquired skills can be exercised at various levels of mastery. Those who have studied the piano and who have practiced diligently certainly are able to play better than those of us who have not. The plain fact is that some people play the piano better than others. And the same is true of riding a bicycle, playing chess, and so forth. Now let‟s stretch this agreement about such skills a little further. Consider the activity of thinking. Obviously, we all think, but it is seldom that we think about thinking. So let's try to stretch our thinking to include thinking about thinking. As we do, and if this does not cause too much of a cramp, we will see that thinking is indeed an activity that has much in common with other acquired skills. -
Topics in Philosophical Logic
Topics in Philosophical Logic The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Litland, Jon. 2012. Topics in Philosophical Logic. Doctoral dissertation, Harvard University. Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:9527318 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA © Jon Litland All rights reserved. Warren Goldfarb Jon Litland Topics in Philosophical Logic Abstract In “Proof-Theoretic Justification of Logic”, building on work by Dummett and Prawitz, I show how to construct use-based meaning-theories for the logical constants. The assertability-conditional meaning-theory takes the meaning of the logical constants to be given by their introduction rules; the consequence-conditional meaning-theory takes the meaning of the log- ical constants to be given by their elimination rules. I then consider the question: given a set of introduction (elimination) rules , what are the R strongest elimination (introduction) rules that are validated by an assertabil- ity (consequence) conditional meaning-theory based on ? I prove that the R intuitionistic introduction (elimination) rules are the strongest rules that are validated by the intuitionistic elimination (introduction) rules. I then prove that intuitionistic logic is the strongest logic that can be given either an assertability-conditional or consequence-conditional meaning-theory. In “Grounding Grounding” I discuss the notion of grounding. My discus- sion revolves around the problem of iterated grounding-claims. -
The Philosophy of Mathematics: a Study of Indispensability and Inconsistency
Claremont Colleges Scholarship @ Claremont Scripps Senior Theses Scripps Student Scholarship 2016 The hiP losophy of Mathematics: A Study of Indispensability and Inconsistency Hannah C. Thornhill Scripps College Recommended Citation Thornhill, Hannah C., "The hiP losophy of Mathematics: A Study of Indispensability and Inconsistency" (2016). Scripps Senior Theses. Paper 894. http://scholarship.claremont.edu/scripps_theses/894 This Open Access Senior Thesis is brought to you for free and open access by the Scripps Student Scholarship at Scholarship @ Claremont. It has been accepted for inclusion in Scripps Senior Theses by an authorized administrator of Scholarship @ Claremont. For more information, please contact [email protected]. The Philosophy of Mathematics: A Study of Indispensability and Inconsistency Hannah C.Thornhill March 10, 2016 Submitted to Scripps College in Partial Fulfillment of the Degree of Bachelor of Arts in Mathematics and Philosophy Professor Avnur Professor Karaali Abstract This thesis examines possible philosophies to account for the prac- tice of mathematics, exploring the metaphysical, ontological, and epis- temological outcomes of each possible theory. Through a study of the two most probable ideas, mathematical platonism and fictionalism, I focus on the compelling argument for platonism given by an ap- peal to the sciences. The Indispensability Argument establishes the power of explanation seen in the relationship between mathematics and empirical science. Cases of this explanatory power illustrate how we might have reason to believe in the existence of mathematical en- tities present within our best scientific theories. The second half of this discussion surveys Newtonian Cosmology and other inconsistent theories as they pose issues that have received insignificant attention within the philosophy of mathematics. -
Redalyc.Logical Consequence for Nominalists
THEORIA. Revista de Teoría, Historia y Fundamentos de la Ciencia ISSN: 0495-4548 [email protected] Universidad del País Vasco/Euskal Herriko Unibertsitatea España ROSSBERG, Marcus; COHNITZ, Daniel Logical Consequence for Nominalists THEORIA. Revista de Teoría, Historia y Fundamentos de la Ciencia, vol. 24, núm. 2, 2009, pp. 147- 168 Universidad del País Vasco/Euskal Herriko Unibertsitatea Donostia-San Sebastián, España Available in: http://www.redalyc.org/articulo.oa?id=339730809003 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Logical Consequence for Nominalists Marcus ROSSBERG and Daniel COHNITZ BIBLID [0495-4548 (2009) 24: 65; pp. 147-168] ABSTRACT: It has repeatedly been argued that nominalistic programmes in the philosophy of mathematics fail, since they will at some point or other involve the notion of logical consequence which is unavailable to the nominalist. In this paper we will argue that this is not the case. Using an idea of Nelson Goodman and W.V.Quine's which they developed in Goodman and Quine (1947) and supplementing it with means that should be nominalistically acceptable, we present a way to explicate logical consequence in a nominalistically acceptable way. Keywords: Philosophy of mathematics, nominalism, logical consequence, inferentialism, Nelson Goodman, W.V. Quine. 1. The Argument from Logical Consequence We do not have any strong convictions concerning the question of the existence or non- existence of abstract objects. We do, however, believe that ontological fastidiousness is prima facie a good attitude to adopt. -
Validity and Soundness
1.4 Validity and Soundness A deductive argument proves its conclusion ONLY if it is both valid and sound. Validity: An argument is valid when, IF all of it’s premises were true, then the conclusion would also HAVE to be true. In other words, a “valid” argument is one where the conclusion necessarily follows from the premises. It is IMPOSSIBLE for the conclusion to be false if the premises are true. Here’s an example of a valid argument: 1. All philosophy courses are courses that are super exciting. 2. All logic courses are philosophy courses. 3. Therefore, all logic courses are courses that are super exciting. Note #1: IF (1) and (2) WERE true, then (3) would also HAVE to be true. Note #2: Validity says nothing about whether or not any of the premises ARE true. It only says that IF they are true, then the conclusion must follow. So, validity is more about the FORM of an argument, rather than the TRUTH of an argument. So, an argument is valid if it has the proper form. An argument can have the right form, but be totally false, however. For example: 1. Daffy Duck is a duck. 2. All ducks are mammals. 3. Therefore, Daffy Duck is a mammal. The argument just given is valid. But, premise 2 as well as the conclusion are both false. Notice however that, IF the premises WERE true, then the conclusion would also have to be true. This is all that is required for validity. A valid argument need not have true premises or a true conclusion. -
Philosophy of Language in the Twentieth Century Jason Stanley Rutgers University
Philosophy of Language in the Twentieth Century Jason Stanley Rutgers University In the Twentieth Century, Logic and Philosophy of Language are two of the few areas of philosophy in which philosophers made indisputable progress. For example, even now many of the foremost living ethicists present their theories as somewhat more explicit versions of the ideas of Kant, Mill, or Aristotle. In contrast, it would be patently absurd for a contemporary philosopher of language or logician to think of herself as working in the shadow of any figure who died before the Twentieth Century began. Advances in these disciplines make even the most unaccomplished of its practitioners vastly more sophisticated than Kant. There were previous periods in which the problems of language and logic were studied extensively (e.g. the medieval period). But from the perspective of the progress made in the last 120 years, previous work is at most a source of interesting data or occasional insight. All systematic theorizing about content that meets contemporary standards of rigor has been done subsequently. The advances Philosophy of Language has made in the Twentieth Century are of course the result of the remarkable progress made in logic. Few other philosophical disciplines gained as much from the developments in logic as the Philosophy of Language. In the course of presenting the first formal system in the Begriffsscrift , Gottlob Frege developed a formal language. Subsequently, logicians provided rigorous semantics for formal languages, in order to define truth in a model, and thereby characterize logical consequence. Such rigor was required in order to enable logicians to carry out semantic proofs about formal systems in a formal system, thereby providing semantics with the same benefits as increased formalization had provided for other branches of mathematics. -
The Ascent from Nominalism Philosophical Studies Series
THE ASCENT FROM NOMINALISM PHILOSOPHICAL STUDIES SERIES Editors: WILFRID SELLARS, University of Pittsburgh KEITH LEHRER, University of Arizona Board of Consulting Editors: J ON A THAN BENNETT, Syracuse University ALLAN GIBBARD, University of Michigan ROBERT STALNAKER, Cornell University ROBERT G. TURNBULL, Ohio State University VOLUME 37 TERR Y PENNER Department of Philosophy, The University of Wisconsin at Madison, U.S.A. THE ASCENT FROM NOMINALISM Some Existence Arguments in Plato's Middle Dialogues D. REIDEL PUBLISHING COMPANY ~~ A MEMBER OF THE KLUWER . ACADEMIC PUBLISHERS GROUP DORDRECHTj BOSTONj LANCASTERjTOKYO Library of Congress Cataloging in Publication Data Penner, Terry, 1936- The ascent from nominalism. (Philosophical studies series; v. 37) Bibliography: p. Includes indexes. 1. Plato. 2. Aristotle. 3. Metaphysics-History. 4. Nominalism-History. I. Title. II. Series. B395.P347 1987 111'.2'0924 86·31641 ISBN-13: 978-94-010-8186-3 e-ISBN-13: 978-94-009-3791-8 DOl: 10.1007/978-94-009-3791-8 Published by D. Reidel Publishing Company, P.O. Box 17, 3300 AA Dordrecht, Holland. Sold and distributed in the U.S.A. and Canada by Kluwer Academic Publishers, 101 Philip Drive, Assinippi Park, Norwell, MA 02061, U.S.A. In all other countries, sold and distributed by Kluwer Academic Publishers Group, P.O. Box 322, 3300 AH Dordrecht, Holland. All Rights Reserved © 1987 by D. Reidel Publishing Company, Dordrecht, Holland Softcover reprint of the hardcover I 5t edition 1987 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical induding photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner ACKNOWLEDGEMENTS Much of this work was conceived and executed between 1971 and 1975, though some of it was done much earlier, and a few bits are quite recent.