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Handbook Vatican 2014
HANDBOOK OF THE WORLD CONGRESS ON THE SQUARE OF OPPOSITION IV Pontifical Lateran University, Vatican May 5-9, 2014 Edited by Jean-Yves Béziau and Katarzyna Gan-Krzywoszyńska www.square-of-opposition.org 1 2 Contents 1. Fourth World Congress on the Square of Opposition ..................................................... 7 1.1. The Square : a Central Object for Thought ..................................................................................7 1.2. Aim of the Congress.....................................................................................................................8 1.3. Scientific Committee ...................................................................................................................9 1.4. Organizing Committee .............................................................................................................. 10 2. Plenary Lectures ................................................................................................... 11 Gianfranco Basti "Scientia una contrariorum": Paraconsistency, Induction, and Formal Ontology ..... 11 Jean-Yves Béziau Square of Opposition: Past, Present and Future ....................................................... 12 Manuel Correia Machuca The Didactic and Theoretical Expositions of the Square of Opposition in Aristotelian logic ....................................................................................................................... 13 Rusty Jones Bivalence and Contradictory Pairs in Aristotle’s De Interpretatione ................................ -
7.1 Rules of Implication I
Natural Deduction is a method for deriving the conclusion of valid arguments expressed in the symbolism of propositional logic. The method consists of using sets of Rules of Inference (valid argument forms) to derive either a conclusion or a series of intermediate conclusions that link the premises of an argument with the stated conclusion. The First Four Rules of Inference: ◦ Modus Ponens (MP): p q p q ◦ Modus Tollens (MT): p q ~q ~p ◦ Pure Hypothetical Syllogism (HS): p q q r p r ◦ Disjunctive Syllogism (DS): p v q ~p q Common strategies for constructing a proof involving the first four rules: ◦ Always begin by attempting to find the conclusion in the premises. If the conclusion is not present in its entirely in the premises, look at the main operator of the conclusion. This will provide a clue as to how the conclusion should be derived. ◦ If the conclusion contains a letter that appears in the consequent of a conditional statement in the premises, consider obtaining that letter via modus ponens. ◦ If the conclusion contains a negated letter and that letter appears in the antecedent of a conditional statement in the premises, consider obtaining the negated letter via modus tollens. ◦ If the conclusion is a conditional statement, consider obtaining it via pure hypothetical syllogism. ◦ If the conclusion contains a letter that appears in a disjunctive statement in the premises, consider obtaining that letter via disjunctive syllogism. Four Additional Rules of Inference: ◦ Constructive Dilemma (CD): (p q) • (r s) p v r q v s ◦ Simplification (Simp): p • q p ◦ Conjunction (Conj): p q p • q ◦ Addition (Add): p p v q Common Misapplications Common strategies involving the additional rules of inference: ◦ If the conclusion contains a letter that appears in a conjunctive statement in the premises, consider obtaining that letter via simplification. -
Two Squares of Opposition: the Conceptual Square Underwrites the Alethic Square’S Validity
1 TWO SQUARES OF OPPOSITION: THE CONCEPTUAL SQUARE UNDERWRITES THE ALETHIC SQUARE’S VALIDITY ABSTRACT I have made explicit an implicit conceptual logic that exists in the English lang- uage and others; its evaluation terms of propositions are coherent|incoherent. This con- trasts with the usual alethic true|false evaluations for statement logic. I call conceptual logic a basement logic; it’s more basic than statement logic. I demonstrate this by show- ing how the long-standard, ever-present Alethic Square of Opposition’s AEIO state- ments’ truth value and the validity of their immediate inferences rests on the Conceptual Square’s (a) coherent propositions and (b) coherent emplacements of substantives and tropes into, respectively, AEIOs’ subjects and predicates. ConceptFunctor operations bear the leutic [Enjoined] modal that governs the coherence of de dicto and de jure grounded propositions. The FactFunctor operation bears the [Allowed] modal that govern coherent emplacement of the world’s substantives and tropes into sentences’ subjects and predicates and, subsequent to that, the truth value of their allied statements. My strategy is (1) to construct a Conceptual Square of Opposition by rewriting the Aletic Square’s AEIO statements as conceptual propositions. (2) If the propositions are coherent by virtue of coherent emplacements of substantives and tropes into their subjects and predicates that turns them into conceptualized substantives and tropes, then, by the Coherence Account of Truth, they entail the truth of the Alethic Squares’ statements and the validity of its traditionally accepted inferences. (3) This is enough to prove conceptual logic is the basement ground for the traditional Alethic Square, and on which any alethic logic rests; and it supports the claims made in (2) above.1 KEY WORDS: Coherence, [Emplace], [Functor], ConceptFunctor, FactFunctor, [Any], collective, distributive, and singular (uses of [Any]), grammatical and semantic subjects and predicates, Concepttual and Alethic Square (of opposition), leutic modal- ities, [Enjoin], [Allow]. -
Logical Extensions of Aristotle's Square
Logical Extensions of Aristotle’s Square Dominique Luzeaux, Jean Sallantin, Christopher Dartnell To cite this version: Dominique Luzeaux, Jean Sallantin, Christopher Dartnell. Logical Extensions of Aristotle’s Square. Logica Universalis, Springer Verlag, 2008, 2, pp.167-187. 10.1007/s11787-007-0022-y. lirmm- 00274314 HAL Id: lirmm-00274314 https://hal-lirmm.ccsd.cnrs.fr/lirmm-00274314 Submitted on 17 Apr 2008 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Logical extensions of Aristotle's square Dominique Luzeaux, Jean Sallantin and Christopher Dartnell Abstract. We start from the geometrical-logical extension of Aristotle's square in [Bla66], [Pel06] and [Mor04], and study them from both syntactic and semantic points of view. Recall that Aristotle's square under its modal form has the following four vertices: A is α, E is :α, I is ::α and O is :α, where α is a logical formula and is a modality which can be defined axiomatically within a particular logic known as S5 (classical or intuitionistic, depending on whether : is involutive or not) modal logic. [B´ez03]has proposed extensions which can be interpreted respectively within paraconsistent and paracomplete logical frameworks. -
Alice in the Wonderful Land of Logical Notions)
The Mystery of the Fifth Logical Notion (Alice in the Wonderful Land of Logical Notions) Jean-Yves Beziau University of Brazil, Rio de Janeiro, Brazilian Research Council and Brazilian Academy of Philosophy [email protected] Abstract We discuss a theory presented in a posthumous paper by Alfred Tarski entitled “What are logical notions?”. Although the theory of these logical notions is something outside of the main stream of logic, not presented in logic textbooks, it is a very interesting theory and can easily be understood by anybody, especially studying the simplest case of the four basic logical notions. This is what we are doing here, as well as introducing a challenging fifth logical notion. We first recall the context and origin of what are here called Tarski- Lindenbaum logical notions. In the second part, we present these notions in the simple case of a binary relation. In the third part, we examine in which sense these are considered as logical notions contrasting them with an example of a non-logical relation. In the fourth part, we discuss the formulations of the four logical notions in natural language and in first- order logic without equality, emphasizing the fact that two of the four logical notions cannot be expressed in this formal language. In the fifth part, we discuss the relations between these notions using the theory of the square of opposition. In the sixth part, we introduce the notion of variety corresponding to all non-logical notions and we argue that it can be considered as a logical notion because it is invariant, always referring to the same class of structures. -
Saving the Square of Opposition∗
HISTORY AND PHILOSOPHY OF LOGIC, 2021 https://doi.org/10.1080/01445340.2020.1865782 Saving the Square of Opposition∗ PIETER A. M. SEUREN Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands Received 19 April 2020 Accepted 15 December 2020 Contrary to received opinion, the Aristotelian Square of Opposition (square) is logically sound, differing from standard modern predicate logic (SMPL) only in that it restricts the universe U of cognitively constructible situations by banning null predicates, making it less unnatural than SMPL. U-restriction strengthens the logic without making it unsound. It also invites a cognitive approach to logic. Humans are endowed with a cogni- tive predicate logic (CPL), which checks the process of cognitive modelling (world construal) for consistency. The square is considered a first approximation to CPL, with a cognitive set-theoretic semantics. Not being cognitively real, the null set Ø is eliminated from the semantics of CPL. Still rudimentary in Aristotle’s On Interpretation (Int), the square was implicitly completed in his Prior Analytics (PrAn), thereby introducing U-restriction. Abelard’s reconstruction of the logic of Int is logically and historically correct; the loca (Leak- ing O-Corner Analysis) interpretation of the square, defended by some modern logicians, is logically faulty and historically untenable. Generally, U-restriction, not redefining the universal quantifier, as in Abelard and loca, is the correct path to a reconstruction of CPL. Valuation Space modelling is used to compute -
Logic-Sensitivity of Aristotelian Diagrams in Non-Normal Modal Logics
axioms Article Logic-Sensitivity of Aristotelian Diagrams in Non-Normal Modal Logics Lorenz Demey 1,2 1 Center for Logic and Philosophy of Science, KU Leuven, 3000 Leuven, Belgium; [email protected] 2 KU Leuven Institute for Artificial Intelligence, KU Leuven, 3000 Leuven, Belgium Abstract: Aristotelian diagrams, such as the square of opposition, are well-known in the context of normal modal logics (i.e., systems of modal logic which can be given a relational semantics in terms of Kripke models). This paper studies Aristotelian diagrams for non-normal systems of modal logic (based on neighborhood semantics, a topologically inspired generalization of relational semantics). In particular, we investigate the phenomenon of logic-sensitivity of Aristotelian diagrams. We distin- guish between four different types of logic-sensitivity, viz. with respect to (i) Aristotelian families, (ii) logical equivalence of formulas, (iii) contingency of formulas, and (iv) Boolean subfamilies of a given Aristotelian family. We provide concrete examples of Aristotelian diagrams that illustrate these four types of logic-sensitivity in the realm of normal modal logic. Next, we discuss more subtle examples of Aristotelian diagrams, which are not sensitive with respect to normal modal logics, but which nevertheless turn out to be highly logic-sensitive once we turn to non-normal systems of modal logic. Keywords: Aristotelian diagram; non-normal modal logic; square of opposition; logical geometry; neighborhood semantics; bitstring semantics MSC: 03B45; 03A05 Citation: Demey, L. Logic-Sensitivity of Aristotelian Diagrams in Non-Normal Modal Logics. Axioms 2021, 10, 128. https://doi.org/ 1. Introduction 10.3390/axioms10030128 Aristotelian diagrams, such as the so-called square of opposition, visualize a number Academic Editor: Radko Mesiar of formulas from some logical system, as well as certain logical relations holding between them. -
Traditional Logic II Text (2Nd Ed
Table of Contents A Note to the Teacher ............................................................................................... v Further Study of Simple Syllogisms Chapter 1: Figure in Syllogisms ............................................................................................... 1 Chapter 2: Mood in Syllogisms ................................................................................................. 5 Chapter 3: Reducing Syllogisms to the First Figure ............................................................... 11 Chapter 4: Indirect Reduction of Syllogisms .......................................................................... 19 Arguments in Ordinary Language Chapter 5: Translating Ordinary Sentences into Logical Statements ..................................... 25 Chapter 6: Enthymemes ......................................................................................................... 33 Hypothetical Syllogisms Chapter 7: Conditional Syllogisms ......................................................................................... 39 Chapter 8: Disjunctive Syllogisms ......................................................................................... 49 Chapter 9: Conjunctive Syllogisms ......................................................................................... 57 Complex Syllogisms Chapter 10: Polysyllogisms & Aristotelian Sorites .................................................................. 63 Chapter 11: Goclenian & Conditional Sorites ........................................................................ -
Universal Machines
Universal Machines In his magisterial Introduction to Logic, Paul Herrick (2013) not only guides the reader through a history of symbolic logic, but he also comments on the various links between logic and the history of computation. Aristotle, 384-322 BCE The Square of Opposition “We have seen that Aristotle’s Square of Opposition can be used to compute the truth-value of one statement given the truth-value of another. Mathematicians calls this type of procedure an algorithm… Aristotle’s Square of Opposition was the first large-scale, general-purpose algorithm in the history of logic. This might help explain why the first person in history to design a mechanical computer was an Aristotelian logician…” “Inspired by Aristotle’s Square of Opposition, Raymond Lull (1232-1315), a medieval logician who was also a Catholic priest, designed a computing machine consisting of two rotating disks, each inscribed with symbols for categorical propositions…” “The disks were aligned in such a way that one could turn a dial and see which statements validly follow from a given statement. Although extremely rudimentary, Lull’s basic idea underlies the modern digital computer...” “For the first time in history, someone had conceived of a machine that takes inputs of a certain sort and then, on the basis of rules of logic, computes an exact answer, which is then read off some other part of the device...” “The first designs in history for machines that compute were designs for mechanical devices that would operate according to the exact laws not of mathematics but of logic” (Herrick 2013: 121-2). -
A New Light on the Nameless Corner of the Square of Oppositions
New Light on the Square of Oppositions and its Nameless Corner Jean-Yves Béziau Institute of Logic and Semiological Research Center University of Neuchâtel, Espace Louis Agassiz 1 CH - 2000 Neuchâtel, Switzerland [email protected] Abstract It has been pointed out that there is no primitive name in natural and formal languages for one corner of the famous square of oppositions. We have all, some and no, but no primitive name for not all. It is true also in the modal version of the square, we have necessary, possible and impossible, but no primitive name for not necessary. I shed here a new light on this mysterious non-lexicalisation of the south- east corner of the square of oppositions, the so-called O-corner, by establishing some connections between negations and modalities. The E-corner, impossible, is a paracomplete negation (intuitionistic negation if the underlying modal logic is S4) and the O-corner, not necessary, is a paraconsistent negation. I argue that the three notions of opposition of the square of oppositions (contradiction, contrariety, subcontrariety) correspond to three notions of negation (classical, paracomplete, paraconsistent). We get a better understanding of these relations of opposition in the perspective of Blanché’s hexagon and furthermore in the perspective of a three dimensional object, a stellar dodecahedron of oppositions that I present at the end of the paper. Contents 1.The non lexicalization of the O-corner of the Square of Oppositions 2.Three oppositions and three negations 3.Some controversies about the theory of oppositions 4.The O corner within the Octagon and the Stellar Dodecahedron of Oppositions 5.Conclusions 6.Bibliography 1 1. -
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 -
The Traditional Square of Opposition and Generalized Quantifiers
The traditional square of opposition and generalized quantifiers∗ Dag Westerst˚ahl University of Gothenburg Abstract The traditional square of opposition dates back to Aristotle’s logic and has been intensely discussed ever since, both in medieval and mod- ern times. It presents certain logical relations, or oppositions, that hold between the four quantifiers all, no, not all, and some. Aristotle and tradi- tional logicians, as well as most linguists today, took all to have existential import, so that “All As are B” entails that there are As, whereas modern logic drops this assumption. Replacing Aristotle’s account of all with the modern one (and similarly for not all) results in the modern version of the square, and there has been much recent debate about which of these two squares is the ‘right’ one. My main point in the present paper is that this question is not, or should not primarily be, about existential import, but rather about pat- terns of negation. I argue that the modern square, but not the traditional one, presents a general pattern of negation one finds in natural language. To see this clearly, one needs to apply the square not just to the four Aristotelian quantifiers, but to other generalized quantifiers of that type. Any such quantifier spans a modern square, which exhibits that pattern of negation but, very often, not the oppositions found in the traditional square. I provide some technical results and tools, and illustrate with sev- eral examples of squares based on quantifiers interpreting various English determiners. The final example introduces a second pattern of negation, which occurs with certain complex quantifiers, and which also is repre- sentable in a square.