Foundations of Mathematics
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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. -
Mathematical Induction - a Miscellany of Theory, History and Technique
Mathematical Induction - a miscellany of theory, history and technique Theory and applications for advanced secondary students Part 4 Peter Haggstrom This work is subject to Copyright. It is a chapter in a larger work. You can however copy this chapter for educational purposes under the Statutory License of the Copyright Act 1968 - Part VB For more information [email protected] Copyright 2009 [email protected] The building blocks of Gödelʼs Theorem The foundations of Gödel’s Theorem (ie his undecidability theorem) are to be found in about 50 papers contained in a book by Jean van Heijenoort:, “From Frege to Gödel: A Source Book in Mathematical Logic, 1879 - 1931”. Every serious logic student has read this book. Van Heijenoort is worth mentioning even if only for his colourful past which is described by Benjamin H Yandell in his book “The Honors Class: Hilbert’s Problems and Their Solvers”, A K Peters, 2002, page 66. I quote in full: “ I assumed van Heijenoort was merely a logician as I gratefully pored over his book and was astounded when I learned that as a young man, in the 1930s, he had followed Leon Trotsky from Turkey to France to Norway to Mexico, as his body guard and secretary. Anita Feferman’s ”From Trotsky to Gödel”: The Life of Jean van Heijenoort” tells van Heijenoort’s remarkable story. Trotsky and his camp were pursued by Stalinist agents; van Heijenoort always packed a gun. Van Heijenoort had an affair with an artist Frida Kahlo. He epitomized cool and was attractive to women, and this continued even after he became a logician, He had grown tired of the rigors of life with Trotsky and traveled to New York in 1939 on a somewhat vague mission. -
Basic Concepts of Set Theory, Functions and Relations 1. Basic
Ling 310, adapted from UMass Ling 409, Partee lecture notes March 1, 2006 p. 1 Basic Concepts of Set Theory, Functions and Relations 1. Basic Concepts of Set Theory........................................................................................................................1 1.1. Sets and elements ...................................................................................................................................1 1.2. Specification of sets ...............................................................................................................................2 1.3. Identity and cardinality ..........................................................................................................................3 1.4. Subsets ...................................................................................................................................................4 1.5. Power sets .............................................................................................................................................4 1.6. Operations on sets: union, intersection...................................................................................................4 1.7 More operations on sets: difference, complement...................................................................................5 1.8. Set-theoretic equalities ...........................................................................................................................5 Chapter 2. Relations and Functions ..................................................................................................................6 -
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. -
The Development of Mathematical Logic from Russell to Tarski: 1900–1935
The Development of Mathematical Logic from Russell to Tarski: 1900–1935 Paolo Mancosu Richard Zach Calixto Badesa The Development of Mathematical Logic from Russell to Tarski: 1900–1935 Paolo Mancosu (University of California, Berkeley) Richard Zach (University of Calgary) Calixto Badesa (Universitat de Barcelona) Final Draft—May 2004 To appear in: Leila Haaparanta, ed., The Development of Modern Logic. New York and Oxford: Oxford University Press, 2004 Contents Contents i Introduction 1 1 Itinerary I: Metatheoretical Properties of Axiomatic Systems 3 1.1 Introduction . 3 1.2 Peano’s school on the logical structure of theories . 4 1.3 Hilbert on axiomatization . 8 1.4 Completeness and categoricity in the work of Veblen and Huntington . 10 1.5 Truth in a structure . 12 2 Itinerary II: Bertrand Russell’s Mathematical Logic 15 2.1 From the Paris congress to the Principles of Mathematics 1900–1903 . 15 2.2 Russell and Poincar´e on predicativity . 19 2.3 On Denoting . 21 2.4 Russell’s ramified type theory . 22 2.5 The logic of Principia ......................... 25 2.6 Further developments . 26 3 Itinerary III: Zermelo’s Axiomatization of Set Theory and Re- lated Foundational Issues 29 3.1 The debate on the axiom of choice . 29 3.2 Zermelo’s axiomatization of set theory . 32 3.3 The discussion on the notion of “definit” . 35 3.4 Metatheoretical studies of Zermelo’s axiomatization . 38 4 Itinerary IV: The Theory of Relatives and Lowenheim’s¨ Theorem 41 4.1 Theory of relatives and model theory . 41 4.2 The logic of relatives . -
Definitions and Nondefinability in Geometry 475 2
Definitions and Nondefinability in Geometry1 James T. Smith Abstract. Around 1900 some noted mathematicians published works developing geometry from its very beginning. They wanted to supplant approaches, based on Euclid’s, which han- dled some basic concepts awkwardly and imprecisely. They would introduce precision re- quired for generalization and application to new, delicate problems in higher mathematics. Their work was controversial: they departed from tradition, criticized standards of rigor, and addressed fundamental questions in philosophy. This paper follows the problem, Which geo- metric concepts are most elementary? It describes a false start, some successful solutions, and an argument that one of those is optimal. It’s about axioms, definitions, and definability, and emphasizes contributions of Mario Pieri (1860–1913) and Alfred Tarski (1901–1983). By fol- lowing this thread of ideas and personalities to the present, the author hopes to kindle interest in a fascinating research area and an exciting era in the history of mathematics. 1. INTRODUCTION. Around 1900 several noted mathematicians published major works on a subject familiar to us from school: developing geometry from the very beginning. They wanted to supplant the established approaches, which were based on Euclid’s, but which handled awkwardly and imprecisely some concepts that Euclid did not treat fully. They would present geometry with the precision required for general- ization and applications to new, delicate problems in higher mathematics—precision beyond the norm for most elementary classes. Work in this area was controversial: these mathematicians departed from tradition, criticized previous standards of rigor, and addressed fundamental questions in logic and philosophy of mathematics.2 After establishing background, this paper tells a story about research into the ques- tion, Which geometric concepts are most elementary? It describes a false start, some successful solutions, and a demonstration that one of those is in a sense optimal. -
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. -
How Peircean Was the “'Fregean' Revolution” in Logic?
HOW PEIRCEAN WAS THE “‘FREGEAN’ REVOLUTION” IN LOGIC? Irving H. Anellis Peirce Edition, Institute for American Thought Indiana University – Purdue University at Indianapolis Indianapolis, IN, USA [email protected] Abstract. The historiography of logic conceives of a Fregean revolution in which modern mathematical logic (also called symbolic logic) has replaced Aristotelian logic. The preeminent expositors of this conception are Jean van Heijenoort (1912–1986) and Don- ald Angus Gillies. The innovations and characteristics that comprise mathematical logic and distinguish it from Aristotelian logic, according to this conception, created ex nihlo by Gottlob Frege (1848–1925) in his Begriffsschrift of 1879, and with Bertrand Rus- sell (1872–1970) as its chief This position likewise understands the algebraic logic of Augustus De Morgan (1806–1871), George Boole (1815–1864), Charles Sanders Peirce (1838–1914), and Ernst Schröder (1841–1902) as belonging to the Aristotelian tradi- tion. The “Booleans” are understood, from this vantage point, to merely have rewritten Aristotelian syllogistic in algebraic guise. The most detailed listing and elaboration of Frege’s innovations, and the characteristics that distinguish mathematical logic from Aristotelian logic, were set forth by van Heijenoort. I consider each of the elements of van Heijenoort’s list and note the extent to which Peirce had also developed each of these aspects of logic. I also consider the extent to which Peirce and Frege were aware of, and may have influenced, one another’s logical writings. AMS (MOS) 2010 subject classifications: Primary: 03-03, 03A05, 03C05, 03C10, 03G27, 01A55; secondary: 03B05, 03B10, 03E30, 08A20; Key words and phrases: Peirce, abstract algebraic logic; propositional logic; first-order logic; quantifier elimina- tion, equational classes, relational systems §0. -
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 . -
Georg Kreisel Correspondence with Jean Van Heijenoort
http://oac.cdlib.org/findaid/ark:/13030/c84q7wxh No online items Guide to the Georg Kreisel Correspondence with Jean van Heijenoort Daniel Hartwig Stanford University. Libraries.Department of Special Collections and University Archives Stanford, California October 2010 Copyright © 2015 The Board of Trustees of the Leland Stanford Junior University. All rights reserved. Note This encoded finding aid is compliant with Stanford EAD Best Practice Guidelines, Version 1.0. Guide to the Georg Kreisel SC0233 1 Correspondence with Jean van Heijenoort Overview Call Number: SC0233 Creator: Kreisel, Georg, 1923- Title: Georg Kreisel correspondence with Jean van Heijenoort Dates: 1949-1981 Physical Description: 6 Linear feet Summary: Correspondence, notes, memoranda, articles and other materials by Professor Georg Kreisel, sent to his colleague, Professor J. van Heijenoort of Harvard University. Includes some correspondence with other colleagues. Language(s): The materials are in English. Repository: Department of Special Collections and University Archives Green Library 557 Escondido Mall Stanford, CA 94305-6064 Email: [email protected] Phone: (650) 725-1022 URL: http://library.stanford.edu/spc Gift of J. van Heijenoort, 1981. Information about Access This collection is open for research. Ownership & Copyright All requests to reproduce, publish, quote from, or otherwise use collection materials must be submitted in writing to the Head of Special Collections and University Archives, Stanford University Libraries, Stanford, California 94304-6064. Consent is given on behalf of Special Collections as the owner of the physical items and is not intended to include or imply permission from the copyright owner. Such permission must be obtained from the copyright owner, heir(s) or assigns.