The Foundations of Linguistics : Mathematics, Models, and Structures
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The Metamathematics of Putnam's Model-Theoretic Arguments
The Metamathematics of Putnam's Model-Theoretic Arguments Tim Button Abstract. Putnam famously attempted to use model theory to draw metaphysical conclusions. His Skolemisation argument sought to show metaphysical realists that their favourite theories have countable models. His permutation argument sought to show that they have permuted mod- els. His constructivisation argument sought to show that any empirical evidence is compatible with the Axiom of Constructibility. Here, I exam- ine the metamathematics of all three model-theoretic arguments, and I argue against Bays (2001, 2007) that Putnam is largely immune to meta- mathematical challenges. Copyright notice. This paper is due to appear in Erkenntnis. This is a pre-print, and may be subject to minor changes. The authoritative version should be obtained from Erkenntnis, once it has been published. Hilary Putnam famously attempted to use model theory to draw metaphys- ical conclusions. Specifically, he attacked metaphysical realism, a position characterised by the following credo: [T]he world consists of a fixed totality of mind-independent objects. (Putnam 1981, p. 49; cf. 1978, p. 125). Truth involves some sort of correspondence relation between words or thought-signs and external things and sets of things. (1981, p. 49; cf. 1989, p. 214) [W]hat is epistemically most justifiable to believe may nonetheless be false. (1980, p. 473; cf. 1978, p. 125) To sum up these claims, Putnam characterised metaphysical realism as an \externalist perspective" whose \favorite point of view is a God's Eye point of view" (1981, p. 49). Putnam sought to show that this externalist perspective is deeply untenable. To this end, he treated correspondence in terms of model-theoretic satisfaction. -
Paul Rastall, a Linguistic Philosophy of Language, Lewiston, Queenston
Linguistica ONLINE. Published: July 10, 2009 http://www.phil.muni.cz/linguistica/art/mulder/mul-001.pdf ISSN 1801-5336 PAUL RASTALL: A LINGUISTIC PHILOSOPHY OF LANGUAGE, LAMPETER – LEWISTON, 2000[*] review article by Jan W. F. Mulder (University of St. Andrews, UK) Introductory note by Aleš Bičan In 2006 I happened to have a short e-mail conversation with Jan Mulder. I asked him for off-prints of his articles, as some of them were rather hard to find. He was so generous to send me, by regular post, a huge packet of them. It took me some time to realize that some of the included writings had never been published. One of them was a manuscript (type- script) of a discussion of a book by Paul Rastall, a former student of his, which was pub- lished in 2000 by The Edwin Press. I naturally contacted Paul Rastall and asked him about the article. He was not aware of it but supported my idea of having it published in Linguis- tica ONLINE. He consequently spoke to Mulder who welcomed the idea and granted the permission. The article below is thus published for the first time. It should be noted, how- ever, that Jan Mulder has not seen its final form. The text is reproduced here as it appears in the manuscript. I have only corrected a few typographical errors here and there. The only significant change is the inclusion of a list of references. Mulder refers to a number of works, but bibliographical information is not pro- vided. I have tried to list all that are mentioned in the article. -
Church's Thesis As an Empirical Hypothesis
Pobrane z czasopisma Annales AI- Informatica http://ai.annales.umcs.pl Data: 27/02/2019 11:52:41 Annales UMCS Annales UMCS Informatica AI 3 (2005) 119-130 Informatica Lublin-Polonia Sectio AI http://www.annales.umcs.lublin.pl/ Church’s thesis as an empirical hypothesis Adam Olszewski Pontifical Academy of Theology, Kanonicza 25, 31-002 Kraków, Poland The studies of Church’s thesis (further denoted as CT) are slowly gaining their intensity. Since different formulations of the thesis are being proposed, it is necessary to state how it should be understood. The following is the formulation given by Church: [CT] The concept of the effectively calculable function1 is identical with the concept of the recursive function. The conviction that the above formulation is correct, finds its confirmation in Church’s own words:2 We now define the notion, […] of an effectively calculable function of positive integers by identifying it with the notion of a recursive function of positive integers […]. Frege thought that the material equivalence of concepts is the approximation of their identity. For any concepts F, G: Concept FUMCS is identical with concept G iff ∀x (Fx ≡ Gx) 3. The symbol Fx should be read as “object x falls under the concept F”. The contemporary understanding of the right side of the above equation was dominated by the first order logic and set theory. 1Unless stated otherwise, the term function in this work always means function defined on the set natural numbers, that is, on natural numbers including zero. I would rather use the term concept than the term notion. -
Mechanized Metatheory for the Masses: the POPLMARK Challenge
University of Pennsylvania ScholarlyCommons Departmental Papers (CIS) Department of Computer & Information Science August 2005 Mechanized Metatheory for the Masses: The POPLMARK Challenge Brian E. Aydemir University of Pennsylvania Aaron Bohannon University of Pennsylvania Matthew Fairbairn University of Cambridge J. Nathan Foster University of Pennsylvania Benjamin C. Pierce University of Pennsylvania, [email protected] See next page for additional authors Follow this and additional works at: https://repository.upenn.edu/cis_papers Recommended Citation Brian E. Aydemir, Aaron Bohannon, Matthew Fairbairn, J. Nathan Foster, Benjamin C. Pierce, Peter Sewell, Dimitrios Vytiniotis, Geoffrey Washburn, Stephanie C. Weirich, and Stephan A. Zdancewic, "Mechanized Metatheory for the Masses: The POPLMARK Challenge", . August 2005. Postprint version. Published in Lecture Notes in Computer Science, Volume 3603, Theorem Proving in Higher Order Logics (TPHOLs 2005), pages 50-65. Publisher URL: http://dx.doi.org/10.1007/11541868_4 This paper is posted at ScholarlyCommons. https://repository.upenn.edu/cis_papers/235 For more information, please contact [email protected]. Mechanized Metatheory for the Masses: The POPLMARK Challenge Abstract How close are we to a world where every paper on programming languages is accompanied by an electronic appendix with machinechecked proofs? We propose an initial set of benchmarks for measuring progress in this area. Based on the metatheory of System F, a typed lambda-calculus with second-order polymorphism, subtyping, and records, these benchmarks embody many aspects of programming languages that are challenging to formalize: variable binding at both the term and type levels, syntactic forms with variable numbers of components (including binders), and proofs demanding complex induction principles. -
9 Alfred Tarski (1901–1983), Alonzo Church (1903–1995), and Kurt Gödel (1906–1978)
9 Alfred Tarski (1901–1983), Alonzo Church (1903–1995), and Kurt Gödel (1906–1978) C. ANTHONY ANDERSON Alfred Tarski Tarski, born in Poland, received his doctorate at the University of Warsaw under Stanislaw Lesniewski. In 1942, he was given a position with the Department of Mathematics at the University of California at Berkeley, where he taught until 1968. Undoubtedly Tarski’s most important philosophical contribution is his famous “semantical” definition of truth. Traditional attempts to define truth did not use this terminology and it is not easy to give a precise characterization of the idea. The under- lying conception is that semantics concerns meaning as a relation between a linguistic expression and what it expresses, represents, or stands for. Thus “denotes,” “desig- nates,” “names,” and “refers to” are semantical terms, as is “expresses.” The term “sat- isfies” is less familiar but also plausibly belongs in this category. For example, the number 2 is said to satisfy the equation “x2 = 4,” and by analogy we might say that Aristotle satisfies (or satisfied) the formula “x is a student of Plato.” It is not quite obvious that there is a meaning of “true” which makes it a semanti- cal term. If we think of truth as a property of sentences, as distinguished from the more traditional conception of it as a property of beliefs or propositions, it turns out to be closely related to satisfaction. In fact, Tarski found that he could define truth in this sense in terms of satisfaction. The goal which Tarski set himself (Tarski 1944, Woodger 1956) was to find a “mate- rially adequate” and formally correct definition of the concept of truth as it applies to sentences. -
Critique of the Church-Turing Theorem
CRITIQUE OF THE CHURCH-TURING THEOREM TIMM LAMPERT Humboldt University Berlin, Unter den Linden 6, D-10099 Berlin e-mail address: lampertt@staff.hu-berlin.de Abstract. This paper first criticizes Church's and Turing's proofs of the undecidability of FOL. It identifies assumptions of Church's and Turing's proofs to be rejected, justifies their rejection and argues for a new discussion of the decision problem. Contents 1. Introduction 1 2. Critique of Church's Proof 2 2.1. Church's Proof 2 2.2. Consistency of Q 6 2.3. Church's Thesis 7 2.4. The Problem of Translation 9 3. Critique of Turing's Proof 19 References 22 1. Introduction First-order logic without names, functions or identity (FOL) is the simplest first-order language to which the Church-Turing theorem applies. I have implemented a decision procedure, the FOL-Decider, that is designed to refute this theorem. The implemented decision procedure requires the application of nothing but well-known rules of FOL. No assumption is made that extends beyond equivalence transformation within FOL. In this respect, the decision procedure is independent of any controversy regarding foundational matters. However, this paper explains why it is reasonable to work out such a decision procedure despite the fact that the Church-Turing theorem is widely acknowledged. It provides a cri- tique of modern versions of Church's and Turing's proofs. I identify the assumption of each proof that I question, and I explain why I question it. I also identify many assumptions that I do not question to clarify where exactly my reasoning deviates and to show that my critique is not born from philosophical scepticism. -
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. -
Warren Goldfarb, Notes on Metamathematics
Notes on Metamathematics Warren Goldfarb W.B. Pearson Professor of Modern Mathematics and Mathematical Logic Department of Philosophy Harvard University DRAFT: January 1, 2018 In Memory of Burton Dreben (1927{1999), whose spirited teaching on G¨odeliantopics provided the original inspiration for these Notes. Contents 1 Axiomatics 1 1.1 Formal languages . 1 1.2 Axioms and rules of inference . 5 1.3 Natural numbers: the successor function . 9 1.4 General notions . 13 1.5 Peano Arithmetic. 15 1.6 Basic laws of arithmetic . 18 2 G¨odel'sProof 23 2.1 G¨odelnumbering . 23 2.2 Primitive recursive functions and relations . 25 2.3 Arithmetization of syntax . 30 2.4 Numeralwise representability . 35 2.5 Proof of incompleteness . 37 2.6 `I am not derivable' . 40 3 Formalized Metamathematics 43 3.1 The Fixed Point Lemma . 43 3.2 G¨odel'sSecond Incompleteness Theorem . 47 3.3 The First Incompleteness Theorem Sharpened . 52 3.4 L¨ob'sTheorem . 55 4 Formalizing Primitive Recursion 59 4.1 ∆0,Σ1, and Π1 formulas . 59 4.2 Σ1-completeness and Σ1-soundness . 61 4.3 Proof of Representability . 63 3 5 Formalized Semantics 69 5.1 Tarski's Theorem . 69 5.2 Defining truth for LPA .......................... 72 5.3 Uses of the truth-definition . 74 5.4 Second-order Arithmetic . 76 5.5 Partial truth predicates . 79 5.6 Truth for other languages . 81 6 Computability 85 6.1 Computability . 85 6.2 Recursive and partial recursive functions . 87 6.3 The Normal Form Theorem and the Halting Problem . 91 6.4 Turing Machines . -
Common Sense for Concurrency and Strong Paraconsistency Using Unstratified Inference and Reflection
Published in ArXiv http://arxiv.org/abs/0812.4852 http://commonsense.carlhewitt.info Common sense for concurrency and strong paraconsistency using unstratified inference and reflection Carl Hewitt http://carlhewitt.info This paper is dedicated to John McCarthy. Abstract Unstratified Reflection is the Norm....................................... 11 Abstraction and Reification .............................................. 11 This paper develops a strongly paraconsistent formalism (called Direct Logic™) that incorporates the mathematics of Diagonal Argument .......................................................... 12 Computer Science and allows unstratified inference and Logical Fixed Point Theorem ........................................... 12 reflection using mathematical induction for almost all of Disadvantages of stratified metatheories ........................... 12 classical logic to be used. Direct Logic allows mutual Reification Reflection ....................................................... 13 reflection among the mutually chock full of inconsistencies Incompleteness Theorem for Theories of Direct Logic ..... 14 code, documentation, and use cases of large software systems Inconsistency Theorem for Theories of Direct Logic ........ 15 thereby overcoming the limitations of the traditional Tarskian Consequences of Logically Necessary Inconsistency ........ 16 framework of stratified metatheories. Concurrency is the Norm ...................................................... 16 Gödel first formalized and proved that it is not possible -
METALOGIC METALOGIC an Introduction to the Metatheory of Standard First Order Logic
METALOGIC METALOGIC An Introduction to the Metatheory of Standard First Order Logic Geoffrey Hunter Senior Lecturer in the Department of Logic and Metaphysics University of St Andrews PALGRA VE MACMILLAN © Geoffrey Hunter 1971 Softcover reprint of the hardcover 1st edition 1971 All rights reserved. No part of this publication may be reproduced or transmitted, in any form or by any means, without permission. First published 1971 by MACMILLAN AND CO LTD London and Basingstoke Associated companies in New York Toronto Dublin Melbourne Johannesburg and Madras SBN 333 11589 9 (hard cover) 333 11590 2 (paper cover) ISBN 978-0-333-11590-9 ISBN 978-1-349-15428-9 (eBook) DOI 10.1007/978-1-349-15428-9 The Papermac edition of this book is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, resold, hired out, or otherwise circulated without the publisher's prior consent, in any form of binding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser. To my mother and to the memory of my father, Joseph Walter Hunter Contents Preface xi Part One: Introduction: General Notions 1 Formal languages 4 2 Interpretations of formal languages. Model theory 6 3 Deductive apparatuses. Formal systems. Proof theory 7 4 'Syntactic', 'Semantic' 9 5 Metatheory. The metatheory of logic 10 6 Using and mentioning. Object language and metalang- uage. Proofs in a formal system and proofs about a formal system. Theorem and metatheorem 10 7 The notion of effective method in logic and mathematics 13 8 Decidable sets 16 9 1-1 correspondence. -
The History of Formal Semantics, Going Beyond What I Know First-Hand
!"#$"##% Introduction ! “Semantics” can mean many different things, since there are many ways to be interested in “meaning”. One 20th century debate: how much common ground across logic, philosophy, and linguistics? The History of ! Formal semantics, which says “much!”, has been shaped over the last 40+ years by fruitful interdisciplinary collaboration among linguists, Formal Semantics philosophers, and logicians. ! In this talk I’ll reflect mainly on the development of formal semantics and to a lesser extent on formal pragmatics in linguistics and philosophy starting in the 1960’s. Barbara H. Partee ! I’ll describe some of the innovations and “big ideas” that have shaped the MGU, May 14, 2011 development of formal semantics and its relation to syntax and to (= Lecture 13, Formal Semantics Spec-kurs) pragmatics, and draw connections with foundational issues in linguistic theory, philosophy, and cognitive science. May 2011 MGU 2 Introduction “Semantics” can mean many different things ! I’m not trained as a historian of linguistics (yet) or of philosophy; what I know best comes from my experience as a graduate student of Chomsky’s ! “Semantics” used to mean quite different things to linguists in syntax at M.I.T. (1961-65), then as a junior colleague of Montague’s at and philosophers, not surprisingly, since different fields have UCLA starting in 1965, and then, after his untimely death in 1971, as one different central concerns. of a number of linguists and philosophers working to bring Montague’s " Philosophers of language have long been concerned with truth and semantics and Chomskyan syntax together, an effort that Chomsky reference, with logic, with how compositionality works, with how himself was deeply skeptical about. -
Object Language and Metalanguage Formal Languages • Sentence
Object Language and Metalanguage Formal Languages • Sentence Logic and Predicate Logic are formal languages. • A formal language is a set of sentences generated by rules of formation from a vocabulary. • The sentences of Sentence Logic and Predicate Logic are not part of natural language (though some may resemble natural-language sentences). • The formal languages Sentence Logic and Predicate Logic are the objects of our study, and as such they are called object languages. The Metalanguage • If we are going to state anything about an object language, we must make use of a language. • We call a language used to study an object language a metalanguage. • In theory, the metalanguage may be identical to or include the object language. – We use English to study English in linguistics. • We will strictly separate our metalanguage (English with some extra technical vocabulary) from our object languages. • Keeping the languages separate allows us to avoid semantical paradox (Tarski). Use and Mention • When we talk about an item of language, we are said to mention it. • Whenever an item of any object language is mentioned, it must be placed within single quotation marks. • We may use English to mention an item of English. – ‘Bush’ has four letters and starts with a ‘B’. – ‘George W. Bush was born in Texas’ is false. – ‘This sentence is false’ is true. Metavariables • We may also use English to mention items of Sentence Logic and Predicate Logic. – ‘⊃’ is a connective of Sentence Logic. – ‘P ⊃ Q’ is a conditional. – If ‘P’ is true and ‘P ⊃ Q’ is true, then ‘Q’ is true.