3.5 Priest's Dialetheism

Total Page:16

File Type:pdf, Size:1020Kb

3.5 Priest's Dialetheism n Young, Gareth (2015) Revenge: dialetheism and its expressive limitations. PhD thesis. http://theses.gla.ac.uk/6415/ Copyright and moral rights for this thesis are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the Author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Glasgow Theses Service http://theses.gla.ac.uk/ [email protected] Revenge: Dialetheism and its Expressive Limitations Gareth Young MA, Mlitt Submitted in fulfilment of the requirements for the degree of Ph.D. Philosophy School of Humanities University of Glasgow September 2014 2 3 Abstract This thesis is about dialetheism and the problem of revenge. More broadly, it is about truth and what the logical paradoxes tell us about the logical behaviour of truth. One of the driving forces behind the contemporary study of truth and paradox is the problem of revenge: that many, perhaps all, available theories of truth, give rise to further paradoxes, invoking central notions of those theories, which demonstrate that the theory cannot express those notions. This sort of expressive limitation, especially if it involves the very notion invoked to diagnose what goes wrong in paradoxical sentences, would normally be thought a decisive point against a given theory of the paradoxes, were it not for the fact that the problem is so pervasive that every currently available theory has, at some point, been argued to suffer from it. Dialetheism, the view that some contradictions are true, has often been thought to be the only view which has a reasonable chance of avoiding the problem. Indeed, the surge of interest in the view since the first publication of Priest’s In Contradiction, in 1987, defending dialetheism, is probably due in large part to the seeming immunity to the revenge problem that Priest’s view possesses. Its virtue, in respect of revenge, is that its ability to accept, without collapse into incoherence, contradictions, allows it to accept any further revenge paradoxes as merely giving more sound arguments for dialetheia (true contradictions). This thesis argues that this appearance of revenge-immunity is mistaken. Dialetheism, too, has its revenge problems. The seeming virtue of dialetheism, that it can accept the contradictions generated by revenge paradoxes without incoherence, also has its drawbacks. This is because dialetheists are not only able, but compelled to accept the contradictions arising from the semantic paradoxes. This means that contradictions can arise in certain areas where they are undesirable. In particular, there are notions which seem to require consistency in order to be expressible. If we can demonstrate, using revenge paradoxes, that, on dialetheism, predicates putatively representing these notions would have to behave inconsistently, then we can demonstrate that dialetheists cannot express the notions. 4 There are many ways one might wish to carve up the different varieties of dialetheism available. I have separated the view into two broad kinds: metatheoretically paraconsistent dialetheism, on the one hand, and metatheoretically consistent dialetheism, on the other. This distinction decides to which variety of revenge problem the version of dialetheism in question is subject. I take each in turn, and argue that they are each subject to expressive limitations brought about by revenge paradox. 5 Revenge: Dialetheism and its Expressive Limitations Contents Abstract .............................................................................................................................................. 3 Acknowledgements ............................................................................................................................ 7 Declaration of Originality Form – Research Degrees ........................................................................ 9 Chapter 1: Introduction .................................................................................................................... 11 Chapter 2: What is Revenge? ........................................................................................................... 13 2.0 Introduction ................................................................................................................................ 13 2.1 The Phenomenon of Revenge ..................................................................................................... 15 2.2 Too Easy Revenge ....................................................................................................................... 18 2.3 Recipes for Revenge .................................................................................................................... 24 2.4 Varieties of Revenge ................................................................................................................... 40 2.5 Chapter Conclusion ..................................................................................................................... 40 Chapter 3: Metatheoretically Paraconsistent Dialetheism ............................................................ 42 3.0 Introduction ................................................................................................................................ 42 3.1 Priest’s Metatheoretically Paraconsistent Dialetheism .............................................................. 43 3.2 The Semantic Paradoxes ............................................................................................................. 44 3.2.1 Paracompletism ....................................................................................................................... 47 3.2.2 Rejecting the T-Scheme ........................................................................................................... 50 3.2.3 Hierarchical Approaches .......................................................................................................... 54 3.3 Set-Theoretic Paradoxes ............................................................................................................. 58 3.3.1 The Inconsistency of Naïve Set Theory .................................................................................... 58 3.3.2 Priest Against Set-Theoretic Orthodoxy .................................................................................. 62 3.3.2.1 Lack of Motivation for the Cumulative Hierarchy ................................................................. 62 3.3.2.2 Category Theory .................................................................................................................... 66 3.3.2.3 Logic ...................................................................................................................................... 69 3.3 Paradoxes of Inclosure ................................................................................................................ 70 3.4 Summary of Priest’s Case for Dialetheism .................................................................................. 73 3.5 Priest’s Dialetheism ..................................................................................................................... 76 3.5.1 The Teleological Account of Truth ........................................................................................... 79 3.5.1.1 Falsity .................................................................................................................................... 81 3.5.1.2 Untruth.................................................................................................................................. 83 3.5.2 Formal Semantics for Priest’s Dialetheism .............................................................................. 86 3.5.2.1 Extensional Connectives ....................................................................................................... 86 6 3.5.2.2 Priest’s Conditional ............................................................................................................... 88 3.5.3 Paraconsistent Set Theory ....................................................................................................... 94 3.5.4 Paraconsistent Metatheory ..................................................................................................... 99 3.6 Chapter Conclusion ................................................................................................................... 103 Chapter 4: Getting Revenge on Metatheoretically Paraconsistent Dialetheism ......................... 104 4.0 Introduction .............................................................................................................................. 104 4.1 Revenge, Just False and Non-Dialetheia ................................................................................... 106 4.2 Inconsistent Validity and Revenge ............................................................................................ 117 4.2.1 Inconsistent Validity with Transparent Truth ........................................................................ 119 4.2.2 Invalidity with a Non-Contraposable T-scheme ...................................................................
Recommended publications
  • Dialetheists' Lies About the Liar
    PRINCIPIA 22(1): 59–85 (2018) doi: 10.5007/1808-1711.2018v22n1p59 Published by NEL — Epistemology and Logic Research Group, Federal University of Santa Catarina (UFSC), Brazil. DIALETHEISTS’LIES ABOUT THE LIAR JONAS R. BECKER ARENHART Departamento de Filosofia, Universidade Federal de Santa Catarina, BRAZIL [email protected] EDERSON SAFRA MELO Departamento de Filosofia, Universidade Federal do Maranhão, BRAZIL [email protected] Abstract. Liar-like paradoxes are typically arguments that, by using very intuitive resources of natural language, end up in contradiction. Consistent solutions to those paradoxes usually have difficulties either because they restrict the expressive power of the language, orelse because they fall prey to extended versions of the paradox. Dialetheists, like Graham Priest, propose that we should take the Liar at face value and accept the contradictory conclusion as true. A logical treatment of such contradictions is also put forward, with the Logic of Para- dox (LP), which should account for the manifestations of the Liar. In this paper we shall argue that such a formal approach, as advanced by Priest, is unsatisfactory. In order to make contradictions acceptable, Priest has to distinguish between two kinds of contradictions, in- ternal and external, corresponding, respectively, to the conclusions of the simple and of the extended Liar. Given that, we argue that while the natural interpretation of LP was intended to account for true and false sentences, dealing with internal contradictions, it lacks the re- sources to tame external contradictions. Also, the negation sign of LP is unable to represent internal contradictions adequately, precisely because of its allowance of sentences that may be true and false.
    [Show full text]
  • Transworld Heir Lines 89
    Transworld Heir Lines 89 It is desirable that symposia be limited to nine; 4 and, It is believable that nine is prime illustrate such contexts. These occurrences ofthe word "nine" are neither Transworld Heir Lines . so vulgar as that in Nine is larger than five DA VID KAPLAN nor so accidental as that in University of California, Los Angeles Canines are larger than felines. Presumably there are no logical or semantical problems concerned with vulgar or accidental occurrences. Vulgar occurrences of "nine" denote a certain number, are open to substitution and generalization, and contribute to the meaning of the containing sentence. Accidental occurrences are A certain kind of linguistic context has come in for increasing attention ! irrelevant to all such concerns. But analysis of the intermediate contexts over the past several years. The occurrences of the word "nine" in produced by "provable," "possible," "permissible," "probable," "be­ lievable, " and "desirable" is neither trivial nor pointless. It is provable in arithmetic that nine is the square of three; Gottlob Frege, who tried to assimilate such intermediate occurrences to It is possible that the number of planets is nine; the vulgar ones by means of a doctrine about ambiguity and indirect deno­ It is permissible that the number of occupants exceed nine; .tation, called such contexts "oblique" or "indirect." W. V. O. Quine, It is probable that the number of enrolled students will be less than who often seems to want to assimilate the intermediate occurrences to nine; accidental ones by means of a doctrine of indissolubility, calls such con­ texts opaque. Copyright © 1978 by David Kaplan.
    [Show full text]
  • LOGIC BIBLIOGRAPHY up to 2008
    LOGIC BIBLIOGRAPHY up to 2008 by L. Geldsetzer © Copyright reserved Download only for personal use permitted Heinrich Heine Universität Düsseldorf 2008 II Contents 1. Introductions 1 2. Dictionaries 3 3. Course Material 4 4. Handbooks 5 5. Readers 5 6. Bibliographies 6 7. Journals 7 8. History of Logic and Foundations of Mathematics 9 a. Gerneral 9 b. Antiquity 10 c. Chinese Antiquity 11 d. Scholastics 12 e. Islamic Medieval Scholastics 12 f. Modern Times 13 g. Contemporary 13 9. Classics of Logics 15 a. Antiquity 15 b. Medieval Scholastics 17 c. Modern and Recent Times 18 d. Indian Logic, History and Classics 25 10. Topics of Logic 27 1. Analogy and Metaphor, Likelihood 27 2. Argumentation, Argument 27 3. Axiom, Axiomatics 28 4. Belief, Believing 28 5. Calculus 29 8. Commensurability, see also: Incommensurability 31 9. Computability and Decidability 31 10. Concept, Term 31 11. Construction, Constructivity 34 12. Contradiction, Inconsistence, Antinomics 35 13. Copula 35 14. Counterfactuals, Fiction, see also : Modality 35 15. Decision 35 16. Deduction 36 17. Definition 36 18. Diagram, see also: Knowledge Representation 37 19. Dialectic 37 20. Dialethism, Dialetheism, see also: Contradiction and Paracon- sistent Logic 38 21. Discovery 38 22. Dogma 39 23. Entailment, Implication 39 24. Evidence 39 25. Falsity 40 26. Fallacy 40 27. Falsification 40 III 28. Family Resemblance 41 2 9. Formalism 41 3 0. Function 42 31. Functors, Junct ors, Logical Constants or Connectives 42 32. Holism 43 33. Hypothetical Propositions, Hypotheses 44 34. Idealiz ation 44 35. Id entity 44 36. Incommensurability 45 37. Incompleteness 45 38.
    [Show full text]
  • Existence As a Real Property
    Francesco Berto Existence as a Real Property The Ontology of Meinongianism For Graham Priest, Long-distance teacher Prologue: Much Ado About Nothing Some philosophers think that something’s having intuitive content is very inconclusive evidence in favor of it. I think it is very heavy evidence in favor of anything, myself. I really don’t know, in a way, what more conclusive evidence one can have about anything, ultimately speaking. –Saul Kripke, Naming and Necessity 1 In an episode of The Today Show of some years ago, Gene Shalit – NBC’s film and book critic, famous for his wits – reviews several books sharing the feature of bearing entertaining titles. The highpoint of the monologue comes with Nonexistent Objects, by the UCLA philosopher Terence Parsons. Shalit wonders how one could write a whole book on things that do not exist!1 This whole book, too, is about things that do not exist. But if one stops to think, one may find that, in a sense, there is nothing special about this. There are, in fact, thousands of books speaking about unreal things. You have probably read quite a few of them: Sir Arthur Conan Doyle’s stories portrait the adventures of the detective Sherlock Holmes; The Lord of the Rings speaks at length of Gandalf the wizard. Doyle represents Sherlock Holmes as a detective living in London, Baker Street (precisely, at number 221b), describes his remarkable observational and deductive abilities, makes of him the arch-enemy of the criminal mastermind Moriarty. J.R.R. Tolkien characterizes Gandalf as a wizard with a pointy hat and a grey robe (a white one, from a certain point of the story onwards), a heavy pipe-herb 1 The anecdote is reported by Roy Sorensen [2003], p.
    [Show full text]
  • Implicit Versus Explicit Knowledge in Dialogical Logic Manuel Rebuschi
    Implicit versus Explicit Knowledge in Dialogical Logic Manuel Rebuschi To cite this version: Manuel Rebuschi. Implicit versus Explicit Knowledge in Dialogical Logic. Ondrej Majer, Ahti-Veikko Pietarinen and Tero Tulenheimo. Games: Unifying Logic, Language, and Philosophy, Springer, pp.229-246, 2009, 10.1007/978-1-4020-9374-6_10. halshs-00556250 HAL Id: halshs-00556250 https://halshs.archives-ouvertes.fr/halshs-00556250 Submitted on 16 Jan 2011 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. Implicit versus Explicit Knowledge in Dialogical Logic Manuel Rebuschi L.P.H.S. – Archives H. Poincar´e Universit´ede Nancy 2 [email protected] [The final version of this paper is published in: O. Majer et al. (eds.), Games: Unifying Logic, Language, and Philosophy, Dordrecht, Springer, 2009, 229-246.] Abstract A dialogical version of (modal) epistemic logic is outlined, with an intuitionistic variant. Another version of dialogical epistemic logic is then provided by means of the S4 mapping of intuitionistic logic. Both systems cast new light on the relationship between intuitionism, modal logic and dialogical games. Introduction Two main approaches to knowledge in logic can be distinguished [1]. The first one is an implicit way of encoding knowledge and consists in an epistemic interpretation of usual logic.
    [Show full text]
  • Starting the Dismantling of Classical Mathematics
    Australasian Journal of Logic Starting the Dismantling of Classical Mathematics Ross T. Brady La Trobe University Melbourne, Australia [email protected] Dedicated to Richard Routley/Sylvan, on the occasion of the 20th anniversary of his untimely death. 1 Introduction Richard Sylvan (n´eRoutley) has been the greatest influence on my career in logic. We met at the University of New England in 1966, when I was a Master's student and he was one of my lecturers in the M.A. course in Formal Logic. He was an inspirational leader, who thought his own thoughts and was not afraid to speak his mind. I hold him in the highest regard. He was very critical of the standard Anglo-American way of doing logic, the so-called classical logic, which can be seen in everything he wrote. One of his many critical comments was: “G¨odel's(First) Theorem would not be provable using a decent logic". This contribution, written to honour him and his works, will examine this point among some others. Hilbert referred to non-constructive set theory based on classical logic as \Cantor's paradise". In this historical setting, the constructive logic and mathematics concerned was that of intuitionism. (The Preface of Mendelson [2010] refers to this.) We wish to start the process of dismantling this classi- cal paradise, and more generally classical mathematics. Our starting point will be the various diagonal-style arguments, where we examine whether the Law of Excluded Middle (LEM) is implicitly used in carrying them out. This will include the proof of G¨odel'sFirst Theorem, and also the proof of the undecidability of Turing's Halting Problem.
    [Show full text]
  • Relevant and Substructural Logics
    Relevant and Substructural Logics GREG RESTALL∗ PHILOSOPHY DEPARTMENT, MACQUARIE UNIVERSITY [email protected] June 23, 2001 http://www.phil.mq.edu.au/staff/grestall/ Abstract: This is a history of relevant and substructural logics, written for the Hand- book of the History and Philosophy of Logic, edited by Dov Gabbay and John Woods.1 1 Introduction Logics tend to be viewed of in one of two ways — with an eye to proofs, or with an eye to models.2 Relevant and substructural logics are no different: you can focus on notions of proof, inference rules and structural features of deduction in these logics, or you can focus on interpretations of the language in other structures. This essay is structured around the bifurcation between proofs and mod- els: The first section discusses Proof Theory of relevant and substructural log- ics, and the second covers the Model Theory of these logics. This order is a natural one for a history of relevant and substructural logics, because much of the initial work — especially in the Anderson–Belnap tradition of relevant logics — started by developing proof theory. The model theory of relevant logic came some time later. As we will see, Dunn's algebraic models [76, 77] Urquhart's operational semantics [267, 268] and Routley and Meyer's rela- tional semantics [239, 240, 241] arrived decades after the initial burst of ac- tivity from Alan Anderson and Nuel Belnap. The same goes for work on the Lambek calculus: although inspired by a very particular application in lin- guistic typing, it was developed first proof-theoretically, and only later did model theory come to the fore.
    [Show full text]
  • From Axioms to Rules — a Coalition of Fuzzy, Linear and Substructural Logics
    From Axioms to Rules — A Coalition of Fuzzy, Linear and Substructural Logics Kazushige Terui National Institute of Informatics, Tokyo Laboratoire d’Informatique de Paris Nord (Joint work with Agata Ciabattoni and Nikolaos Galatos) Genova, 21/02/08 – p.1/?? Parties in Nonclassical Logics Modal Logics Default Logic Intermediate Logics (Padova) Basic Logic Paraconsistent Logic Linear Logic Fuzzy Logics Substructural Logics Genova, 21/02/08 – p.2/?? Parties in Nonclassical Logics Modal Logics Default Logic Intermediate Logics (Padova) Basic Logic Paraconsistent Logic Linear Logic Fuzzy Logics Substructural Logics Our aim: Fruitful coalition of the 3 parties Genova, 21/02/08 – p.2/?? Basic Requirements Substractural Logics: Algebraization ´µ Ä Î ´Äµ Genova, 21/02/08 – p.3/?? Basic Requirements Substractural Logics: Algebraization ´µ Ä Î ´Äµ Fuzzy Logics: Standard Completeness ´µ Ä Ã ´Äµ ¼½ Genova, 21/02/08 – p.3/?? Basic Requirements Substractural Logics: Algebraization ´µ Ä Î ´Äµ Fuzzy Logics: Standard Completeness ´µ Ä Ã ´Äµ ¼½ Linear Logic: Cut Elimination Genova, 21/02/08 – p.3/?? Basic Requirements Substractural Logics: Algebraization ´µ Ä Î ´Äµ Fuzzy Logics: Standard Completeness ´µ Ä Ã ´Äµ ¼½ Linear Logic: Cut Elimination A logic without cut elimination is like a car without engine (J.-Y. Girard) Genova, 21/02/08 – p.3/?? Outcome We classify axioms in Substructural and Fuzzy Logics according to the Substructural Hierarchy, which is defined based on Polarity (Linear Logic). Genova, 21/02/08 – p.4/?? Outcome We classify axioms in Substructural and Fuzzy Logics according to the Substructural Hierarchy, which is defined based on Polarity (Linear Logic). Give an automatic procedure to transform axioms up to level ¼ È È ¿ ( , in the absense of Weakening) into Hyperstructural ¿ Rules in Hypersequent Calculus (Fuzzy Logics).
    [Show full text]
  • Absolute Contradiction, Dialetheism, and Revenge
    THE REVIEW OF SYMBOLIC LOGIC,Page1of15 ABSOLUTE CONTRADICTION, DIALETHEISM, AND REVENGE FRANCESCO BERTO Department of Philosophy, University of Amsterdam and Northern Institute of Philosophy, University of Aberdeen Abstract. Is there a notion of contradiction—let us call it, for dramatic effect, “absolute”— making all contradictions, so understood, unacceptable also for dialetheists? It is argued in this paper that there is, and that spelling it out brings some theoretical benefits. First it gives us a foothold on undisputed ground in the methodologically difficult debate on dialetheism. Second, we can use it to express, without begging questions, the disagreement between dialetheists and their rivals on the nature of truth. Third, dialetheism has an operator allowing it, against the opinion of many critics, to rule things out and manifest disagreement: for unlike other proposed exclusion-expressing-devices (for instance, the entailment of triviality), the operator used to formulate the notion of absolute contradiction appears to be immune both from crippling expressive limitations and from revenge paradoxes—pending a rigorous nontriviality proof for a formal dialetheic theory including it. Nothing is, and nothing could be, literally both true and false. [. ] That may seem dogmatic. And it is: I am affirming the very thesis that [the dialetheists] have called into question and—contrary to the rules of debate—I decline to defend it. Further, I concede that it is indefensible against their challenge. They have called so much into question that I have no foothold on undisputed ground. So much the worse for the demand that philosophers always must be ready to defend their theses under the rules of debate.
    [Show full text]
  • Bunched Hypersequent Calculi for Distributive Substructural Logics
    EPiC Series in Computing Volume 46, 2017, Pages 417{434 LPAR-21. 21st International Conference on Logic for Programming, Artificial Intelligence and Reasoning Bunched Hypersequent Calculi for Distributive Substructural Logics Agata Ciabattoni and Revantha Ramanayake Technische Universit¨atWien, Austria fagata,[email protected]∗ Abstract We introduce a new proof-theoretic framework which enhances the expressive power of bunched sequents by extending them with a hypersequent structure. A general cut- elimination theorem that applies to bunched hypersequent calculi satisfying general rule conditions is then proved. We adapt the methods of transforming axioms into rules to provide cutfree bunched hypersequent calculi for a large class of logics extending the dis- tributive commutative Full Lambek calculus DFLe and Bunched Implication logic BI. The methodology is then used to formulate new logics equipped with a cutfree calculus in the vicinity of Boolean BI. 1 Introduction The wide applicability of logical methods and their use in new subject areas has resulted in an explosion of new logics. The usefulness of these logics often depends on the availability of an analytic proof calculus (formal proof system), as this provides a natural starting point for investi- gating metalogical properties such as decidability, complexity, interpolation and conservativity, for developing automated deduction procedures, and for establishing semantic properties like standard completeness [26]. A calculus is analytic when every derivation (formal proof) in the calculus has the property that every formula occurring in the derivation is a subformula of the formula that is ultimately proved (i.e. the subformula property). The use of an analytic proof calculus tremendously restricts the set of possible derivations of a given statement to deriva- tions with a discernible structure (in certain cases this set may even be finite).
    [Show full text]
  • Lecture Notes on Constructive Logic: Overview
    Lecture Notes on Constructive Logic: Overview 15-317: Constructive Logic Frank Pfenning Lecture 1 August 29, 2017 1 Introduction According to Wikipedia, logic is the study of the principles of valid infer- ences and demonstration. From the breadth of this definition it is immedi- ately clear that logic constitutes an important area in the disciplines of phi- losophy and mathematics. Logical tools and methods also play an essential role in the design, specification, and verification of computer hardware and software. It is these applications of logic in computer science which will be the focus of this course. In order to gain a proper understanding of logic and its relevance to computer science, we will need to draw heavily on the much older logical traditions in philosophy and mathematics. We will dis- cuss some of the relevant history of logic and pointers to further reading throughout these notes. In this introduction, we give only a brief overview of the goal, contents, and approach of this class. 2 Topics The course is divided into four parts: I. Proofs as Evidence for Truth II. Proofs as Programs III. Proof Search as Computation IV. Substructural and Modal Logics LECTURE NOTES AUGUST 29, 2017 L1.2 Constructive Logic: Overview Proofs are central in all parts of the course, and give it its constructive na- ture. In each part, we will exhibit connections between proofs and forms of computations studied in computer science. These connections will take quite different forms, which shows the richness of logic as a foundational discipline at the nexus between philosophy, mathematics, and computer science.
    [Show full text]
  • Applications of Non-Classical Logic Andrew Tedder University of Connecticut - Storrs, [email protected]
    University of Connecticut OpenCommons@UConn Doctoral Dissertations University of Connecticut Graduate School 8-8-2018 Applications of Non-Classical Logic Andrew Tedder University of Connecticut - Storrs, [email protected] Follow this and additional works at: https://opencommons.uconn.edu/dissertations Recommended Citation Tedder, Andrew, "Applications of Non-Classical Logic" (2018). Doctoral Dissertations. 1930. https://opencommons.uconn.edu/dissertations/1930 Applications of Non-Classical Logic Andrew Tedder University of Connecticut, 2018 ABSTRACT This dissertation is composed of three projects applying non-classical logic to problems in history of philosophy and philosophy of logic. The main component concerns Descartes’ Creation Doctrine (CD) – the doctrine that while truths concerning the essences of objects (eternal truths) are necessary, God had vol- untary control over their creation, and thus could have made them false. First, I show a flaw in a standard argument for two interpretations of CD. This argument, stated in terms of non-normal modal logics, involves a set of premises which lead to a conclusion which Descartes explicitly rejects. Following this, I develop a multimodal account of CD, ac- cording to which Descartes is committed to two kinds of modality, and that the apparent contradiction resulting from CD is the result of an ambiguity. Finally, I begin to develop two modal logics capturing the key ideas in the multi-modal interpretation, and provide some metatheoretic results concerning these logics which shore up some of my interpretive claims. The second component is a project concerning the Channel Theoretic interpretation of the ternary relation semantics of relevant and substructural logics. Following Barwise, I de- velop a representation of Channel Composition, and prove that extending the implication- conjunction fragment of B by composite channels is conservative.
    [Show full text]