The philosophy departments of Salzburg\, Irvine\, and Munich have a strong tradition in logic and philosophy of science. \; This second in a series of workshops brings together scholars from each of the three departments to present talks on various topics in the sciences. \; \;

\nSCHEDULE of TALKS:

\nFRIDAY

\n8:30: Continental Breakfast

\n9:00: Jeff Barrett (UCI) *The Coevolution of Theory and Language*

10:00: Break

\n10:15: Neil Dewar (Munich) *Ramsey equivalence*

In this talk\, I will critique the claim that a theory&rsquo\;s Ramsey sentence (or something like it) is a good candidate for encoding that theory&rsquo\;s structural content. To do so\, I use the following observation: if a Ramsey-style sentence did encode a theory&rsquo\;s structural content\, then two theories would be structurally equivalent just in case they have logically equivalent Ramsey sentences. I then argue that this criterion for structural equivalence is implausible\, even under various modifications of the Ramsey-sentence proposal: the use of frame or Henkin semantics\, the use of full modal semantics\, or the use of modal Henkin semantics.

\n11:15: Coffee Break

\n11:45: Lena Zuchowski (Salzburg) *Revisiting the heated-disk world*

During SIM2015\, I first presented a description of Poincare's heated-disk world thought experiment. Here\, I will present an extension of this work: an interpretation of the thought experiment as an illustration of Poincare's conventionalism about space. I will argue that Poincare's geometrical conventionalism as reconstructed from the heated-disk world thought experiment places less emphasis on a free choice between geometries than is traditionally assumed. Instead\, it appears to constitute a warning against epistemic complacency about the perceptual accessibility of the properties of space. \;

\n12:45: LUNCH

\n1:45: Cailin O&rsquo\;Connor (UCI) *Games and Kinds*

In response to those who argue for `property cluster' views of natural kinds\, I use evolutionary models of sim-max games to assess the claim that linguistic terms will appropriately track sets of objects that cluster in property spaces. As I show\, there are two sorts of ways this can fail to happen. First\, evolved terms that do respect property structure in some senses can be conventional nonetheless. Second\, and more crucially\, because the function of linguistic terms is to facilitate successful action in the world\, when such success is based on something other than property clusters\, we should not expect our terms to track those clusters. The models help make this second point salient by highlighting a dubious assumption underlying the cluster kinds view---that property clusters lead to successful generalization and induction in a straightforward way. As I point out\, those who support property cluster kinds as natural can revert to a promiscuous realism in response to these arguments.

\n2:45: Break

\n3:00: Laurenz Hudetz (Salzburg) *Theory equivalence and imaginary elements*

Philosophers of science have recently developed increased interest in formal criteria of theory equivalence (André\;ka\, Madará\;sz and Né\;meti 2008\, Barrett and Halvorson 2016\, Halvorson 2016\, Weatherall 2016). Three of the most important criteria presently discussed are:

\n(1) definitional equivalence (2) generalised definitional equivalence (or generalised bi-interpretability)\, (3) (definable) categorical equivalence.

\nAfter presenting these criteria and their motivations\, I address questions about their limitations and questions about their relationships to each other\, in particular:

\n(a) For which theories does definable categorical equivalence imply generalised bi-interpretability? \; (b) For which theories does generalised bi-interpretability imply definitional equivalence?

\n4:00: Coffee Break

\n4:30: Lavinia Picollo (LMU) *Deflationism and Conservativity*

A wide variety of claims is often associated with deflationism about truth\, including the idea that truth is metaphysically thin\, not a substantial property. This has been interpreted by Shapiro\, Ketland\, Field\, and others as asserting that truth has no explanatory power\, which in turn\, has been taken to mean that axiomatic truth theories should be conservative over their respective base systems. This is problematic as many intuitively appealing truth theories violate the conservativity requirement. As a consequence\, the deflationist position is often deemed untenable. \; We argue that this line of reasoning is fundamentally misguided\, as it draws upon a misconception of deflationism. We first provide a historical account of deflationism\, based on which we put forward a rational reconstruction of the actual position. According to this rational reconstruction\, the main theme of deflationism is that the truth predicate&rsquo\;s only purpose in natural language is to emulate higher-order quantification within first-order single-sorted languages. We argue that metaphors such as &ldquo\;truth is not a substantial property&rdquo\; are meant to emphasise that truth is a property that is expressed by a mere logical or quasi-logical (depending on how higher-order quantification is to be understood) expressive devise\, and nothing more. As a consequence\, we should not rush into concluding that truth cannot have any explanatory power\, or that axiomatic truth theories must be conservative over their corresponding base systems. We maintain that\, according to deflationism\, truth should have as much explanatory power as higher-order logics do\, and truth theories should be as conservative as higher-order logics are. In the light of the well-known results of non-conservativity of\, e.g. second-order arithmetic over its first-order counterpart\, we conclude that deflationists are not committed in any way to adopting conservative theories of truth.

\nSATURDAY

\n8:30: Catered Continental Breakfast

\n9:00: Simon Huttegger &\; Sean Walsh (UCI) *Schnorr Randomness and Lé\;vi's Martingale Convergence Theorem*

Much recent work in algorithmic randomness concerns characterizations of randomness in terms of the almost everywhere behavior of suitably effectivized versions of functions from analysis or probability. In this talk\, we take a look at Lé\;vi's Martingale Convergence Theorem from this perspective. We note that much of Pathak\, Rojas\, and Simpson&rsquo\;s work on Schnorr randomness and the Lebesgue Differentiation Theorem in the Euclidean context carries over to Lé\;vi's Martingale Convergence Theorem in the Cantor space context. We discuss the methodological choices one faces in choosing the appropriate mode of effectivization and the potential bearing of these results on Schnorr&rsquo\;s critique of Martin-Lö\;f. We also discuss the consequences of our result for the Bayesian model of learning.

\n10:00: Break

\n10:15: Lorenzo Rossi (Salzburg) *Generalized Revenge*

Since Saul Kripke&rsquo\;s (1975) paper\, much work has been devoted to solving the truth-theoretical paradoxes by restricting classical logic. In this paper\, we present a *revenge argument *to the effect that the main non-classical solutions breed new paradoxes that they are unable to block. Current non-classical theories of truth feature two kinds of sentences: sentences that satisfy all the principles of classical logic\, and sentences that satisfy such principles only on pain of triviality. However\, none of the main \;non-classical \;theories (paracomplete\, paraconsistent\, non-contractive\, non-transitive) can draw such a distinction. This is problematic for two reasons. First\, the target distinction is a fundamental fact about non-classical theories&mdash\;one that encodes a minimal lesson to be learned from the semantic paradoxes. Second\, the distinction allows non-classical theories to recover classical mathematics. \;Different \;non-classical theories of truth offer different explanations of local failures of classical principles: while specific revenge paradoxes have been targeted at some of these accounts\, we aim to offer a unified revenge argument that applies to (essentially) all* *non-classical approaches. \;Our argument is closely related to a revenge paradox recently put forward by Andrew Bacon (2015) against *classical *theories of truth. Bacon argues that such theories are committed to distinguishing between sentences that satisfy the equivalence of *A *and &lsquo\;*A *is true&rsquo\; and those that don&rsquo\;t. Bacon&rsquo\;s result shows that\, for a large class of classical theories\, the distinction between sentences that satisfy the equivalence and sentences that don&rsquo\;t cannot be expressed. Similarly\, our results show that\, for a large class of non-classical theories\, the distinction between sentences that satisfy all classical principles and sentences that don&rsquo\;t can only be expressed on pain of triviality.

11:15: Coffee Break

\n11:45: Norbert Gratzl (Munich) A Defense of Classical Logic

\nClassical logic is a success story. Having said this there is no lack of criticism. One major critical point is that in some formalizations of classical logic\, foremost Gentzen's LK (and its kin)\, do have multiple conclusions. This paper consists essentially of two major building blocks: the first one is to discuss both some aspects of reasoning as formalized in classical logic and some aspects of proof-theoretic semantics instantiated by Gentzen's LK-systems. The second major building block contains (a) the propositional part and (b) a quanticational part of a single conclusion sequent calculus based on hyperseqeunts.

\n*Attendance is free\, but RSVPs are encouraged prior to February 28\, 2017. Please contact Patty Jones\, patty.jones@uci.edu\, for further information.*