Summer School: A map through the land of dragons. Syntax, Truth, and Paradox

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New College Library, Oxford, BT1.70.2 © Courtesy of the Warden and Scholars of New College, Oxford

Volker Halbach and Lorenzo Rossi will provide an introduction to the theory of the semantic paradoxes and discuss their proposed solutions, analyses, and their philosophical relevance. The liar and related paradoxes do not only affect the notion of truth, but others that are central to philosophy such as necessity, apriority, and future truth. We will study the properties of such sentences as The sentence in italic on this page is not true in a precise formal setting. Participants are not expected to be familiar with techniques such as arithmetization and diagonalization. Bypassing the unnecessary mathematical tools by using an axiomatic syntax theory, we will still provide a formally precise account and proceed swiftly to the philosophical core of the discussions around the paradoxes. In particular, we will discuss the effect of paradoxes on the expressive power of truth, necessity, and related notions, as well as their impact on the foundations of semantics. We will also cover a wide variety of paradoxes such as the Visser-Yablo, the Knower, McGee's, and the No Future paradox. We will critically discuss a gamut of conceptions of paradoxicality, applying them to the study of the various kinds of paradoxes we have introduced, and we will investigate their connection with some of the main formal theories of truth.

Most of the content will be based on Graham Leigh's and Volker Halbach's new book The Road to Paradox: A Guide to Syntax, Truth, and Modality, which is scheduled to appear with Cambridge University Press in January 2024. The summer school, however, will be self-contained and all relevant teaching materials will be supplied to participants. Moreover, the course givers are happy to adjust their plans to the wishes and preferences of the audience to some extent. Hence there may be some deviations, especially in the later parts.

Participants who would like to prepare themselves in the best way for the summer school can have a look at the attached annotated bibliography. 

Volker Halbach

Volker Halbach is Professor of Philosophy at the University of Oxford and Fellow of New College, Oxford. His main interests are in logic and especially the theory of truth. He is the author of the Axiomatic Theories of Truth (2011), The Logic Manual (2010), and other books. His new book The Road to Paradox: A Guide to Syntax, Truth, and Modality, which is close to the topics of the summer school, is scheduled to be published in early 2024.

Lorenzo Rossi

Lorenzo Rossi is Assistant Professor at the University of Turin (Department of Philosophy and Education, and Center for Logic, Language, and Cognition (LLC)). His main interests are in logic, and he has worked on theories of truth, semantic paradoxes, the semantics of quantifiers, indicative conditionals, and vagueness. His first monograph (Truth and Paradox in Context, with J. Murzi) is under contract with OUP.

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  • Schedule of the Summer School

    Here is a provisional schedule of the summer school.

     

    Monday 17

     

    3.30pm-4pm

    Welcome

    4pm-5.30pm

    Introduction. A Map through the land of dragons (Halbach & Rossi)

    6pm

    Drinks at TBD

    Tuesday 18

     

    9.30am-10.30am

    A theory of expressions (Halbach)

    I introduce a theory of syntax that is sufficient for proving Gödel's diagonal lemma. No previous knowledge of the techniques commonly used in the lemma is assumed (such as coding of syntax, the theory of computability etc.). 

    10.30am-11am

    Coffee break

    11am-1pm

    A theory of expressions (Halbach)

    I will look at the connection of syntax-free paradoxes such as Russell's paradox and the paradoxes with diagonalization. I discuss whether truth, necessity, and other notions should be attributed to propositions, sentences, or other objects.

    1pm-3pm

    Lunch break

    3pm-4pm

    What is a semantic paradox? Some preliminary coordinates (Rossi)

    I will present the difference between paradoxical sentences and paradoxical arguments, and that between proof-theoretic and model-theoretic characterizations of paradoxicality. I will also stress the philosophical significance of semantic paradoxes, for both the expressive power of truth (blind ascriptions, blind arguments), and truth-conditional semantics. Finally, I will present the Inclosure approach to paradoxes.

    4.30pm

    Presentations by the participants // Discussion sessions // Exercise session

    Wednesday 19

     

    9.30am-10.30am

    The paradoxes (Halbach)

    The diagonal lemma is used to prove some basic results such as the liar paradox,Tarski's theorem on the undefinability of truth, and Montague's paradox. 

    10.30am-11am

    Coffee break

    11am-1pm

    The paradoxes (Halbach)

    Some refinements of the diagonal lemma are employed to prove Yablo's paradox, Visser's paradox of ill-founded truth hierarchies, and McGee's omega-inconsistency theorem.

    1pm-3pm

    Lunch break

    3pm-4pm

    Conceptions of paradoxicality (I) (Rossi)

    The naive conception of paradoxicality, the discussion of paradoxicality and derivability, and the relations with Löb's Theorem are discussed before turning to the proof-theoretic conception, i.e. paradoxicality as non-normalizability.

    4.30pm

    Presentations by the participants // Discussion sessions // Exercise session

    Thursday 20

     

    9.30am-10.30am

    Possible-worlds analysis of the paradoxes (Halbach)

    I discuss a possible-worlds analysis of the paradoxes. 

    10.30am-11am

    Coffee Break

    11am-12pm

    Possible-worlds analysis of the paradoxes (Halbach)

    The previously introduced analysis will be used to argue that ill-foundedness is at the root of many paradoxes.

    12pm-2pm

    Lunch break

    2pm-4pm

    Conceptions of paradoxicality (II) (Rossi)

    After having introduced the graph-theoretic conception (structural features of paradoxical sentences), I turn to a discussion of ill-foundedness, focusing on circularity and infinitely descending chains.

    4.30pm

    Presentations by the participants // Discussion sessions // Exercise session

    Friday 21

     

    9.30am-10.30am

    Conceptions of paradoxicality (III) (Rossi)

    The Kripkean conception of paradoxicality is introduced, followed by the revision-theoretic one.

    10.30am-11am

    Coffee Break

    11am-1pm

    Truth! (Halbach)

    A more powerful syntax theory is introduced that permits the study of axiomatic theories of truth such as basic disquotational theories, the Kripke-Feferman and Friedman-Sheard theory.

    1pm-3pm

    Lunch break

    3pm-4pm

    Wrap-up (Halbach & Rossi)

     

     

    Besides the one on the first day, a second drink will be organized and offered on another evening, after the sessions. The precise day will be decided later on depending on the weather, for there is a nice walk to reach and come back from that place.

  • Practical Information

    a) Dates:
    Monday 17 - Friday 21, June 2024

    b) Location:
    West Campus USI
    Via Buffi, 13
    Lugano, Switzerland

    c) How to apply:
    By sending a copy of the CV, a one-page motivation letter and a reference letter from a supervisor or colleague to [email protected].
    The deadline for applications is February 15, 2024.

    d) Who can attend?
    Application is open to both graduate students and early career researchers.

    e) Fees The fee for accepted participants is 400.- Swiss francs. It includes participation in the summer school, coffee breaks, 4 lunches and 2 drinks (one on the first evening and a second on another evening). 

    f) Certificate of participation:
    Participants who wish to receive a certificate of participation can ask for it at the end of the last day of the Summer School.

    g) Housing Recommendations:

    AirBnb

    Lugano Youth Hostel
    www.luganoyouthhostel.ch – ca. 30 CHF per night (bunkbed).
    Via Cantonale 13, 6942 Savosa, Switzerland +41 91 966 27 28

    Montarina Hostel
    www.montarina.com – ca. 90 CHF and 160CHF per night (shared rooms).
    Via Montarina 1, 6900 Lugano, Switzerland +41 91 966 72 72

    Victoria au Lac
    www.victoriahotel.ch/en/home - ca. 70 CHF per night (room).
    Via Generale Guisan 3, 6900 Paradiso, Switzerland +41 91 994 20 31

    Hotel Pestalozzi
    www.pestalozzi-lugano.ch/ - ca. 80 CHF per night (room) .
    Piazza Indipendenza 9, 6901 Lugano, Switzerland +41 91 921 46 46

    Hotel Ceresio
    www.hotelceresio.ch/ - ca. 80CHF per night (room).
    Via Serafino Balestra 19, 6900 Lugano, Switzerland +41 91 923 10 44

    Ibis Budget Lugano Paradiso
    https://all.accor.com/hotel/6781/index.en.shtml?utm_campaign=seo+maps&utm_medium=seo+maps&utm_source=google+Maps – ca. 100 CHF per night (bedroom).
    Via Geretta 10a, 6900 Paradiso, Switzerland +41 91 986 19 09

    Hotel Zurigo Downtown
    www.hotelzurigo.ch/ - ca. 120 CHF per night (room).
    Corso Enrico Pestalozzi 13, 6900 Lugano, Switzerland +41 91 923 43 43

    Hotel Admiral
    https://www.luganohoteladmiral.com/en/ - ca. 140 CHF – 200 CHF per night (bedroom).
    Via Geretta 15, 6902 Paradiso, Switzerland +41 91 986 19 09

    Hotel Lido Seegarten
    www.hotellido-lugano.com/en/ - ca. 175 CHF per night (bedroom).
    Via Castagnola 22/24, 6900 Lugano, Switzerland +41 91 973 63 63