Conferences

Conferences organized by ConceptLab.

2022

Engineering the Concept of Collection

Time and place: June 20, 2022–June 21, 2022, Georg Morgenstiernes hus and on Zoom

The history of mathematics and philosophy have seen many different concepts of collection: a set (understood as a gathering into one of previously available objects), a class (understood as defined by its membership condition, not by its members), a mereological sum, etc. Indeed, even a plurality (i.e. many objects) and a concept can be seen as a collection, since it makes sense to talk about their members (or instances).

Alongside these longstanding debates about the nature of collections, there are also questions of how exactly each conception should be made precise. Recent attempts to make sense of the ontology of combinatorial sets, for example, have proposed very different pictures of what they are like. This is especially clear in the debates on the nature of our thought concerning `the’ universe of sets: Does our concept of (combinatorial) set suffice to determine a unique and maximal universe, or does our concept and talk of sets admit of different multifarious interpretations?

These observations raise some general philosophical-mathematical questions. What concepts of collection do we have? Which, if any, of these concepts should we use? Or should we “(re-)engineer” one or more concepts of collection to produce concepts that are fit for purpose?

Further question may include

Should we use a single concept of collection or different concepts for different purposes? (Remember George Boolos: “I thought that set theory was supposed to be a theory about all, `absolutely' all, the collections that there are”.)
Specifically, do we need both a combinatorial concept of set and a logical concept of class (cf. Parsons 1974, Maddy 1983, Linnebo 2006)?
Should we strive for a single true theory based on one or more “correct” concepts of collection, or be pluralists and accept a multitude of equally legitimate, but often competing, theories?
Can recent views on the nature of combinatorial sets (e.g. Hamkins, Linnebo, Woodin) be understood as instances of conceptual engineering?
Speakers: Carolin Antos (Universität Konstanz), Neil Barton (University of Oslo), Tim Button (University College London), Herman Cappelen (University of Hong Kong and University of Oslo), Laura Crosilla (University of Oslo), Kentaro Fujimoto (University of Bristol), Luca Incurvati (University of Amsterdam), Øystein Linnebo (University of Oslo), Stewart Shapiro (Ohio State University and University of Oslo)

The workshop will be hybrid (in-person and online). Registration is free but is required to attend the workshop. Please fill in this form to register.
Registration deadline: 19th of June 2022, 5 pm (CET). You will receive the Zoom invite by email in the evening of the 19th of June.
If you plan to attend in person in Oslo, please let the organisers know as soon as possible and in any case by the 10th of June.

Program

20th June, Georg Morgenstiernes hus, Room 652 - (all times are in CET)

10:30-11:45 Herman Cappelen and Øystein Linnebo: Engineering the concept of collection: introductory remarks
11:45-13:00 Lunch
13:00-14:15 Luca Incurvati: Engineering the concept of set and engineering the concept of objectified property
14:15-14:30 Break
14:30-15:45 Kentaro Fujimoto: Plural, infinity, and impredicativity
15:45-16:00 Break
16:00-17:15 Laura Crosilla: On Weyl’s predicative concept of set

21st June, Georg Morgenstiernes hus, Room 452

10:30-11:45 Tim Button: MOON theory: Mathematical Objects with Ontological Neutrality
11:45-12:00 Break
12:00-13:15 Neil Barton: Engineering Set-Theoretic Concepts
13:15-14:15 Lunch
14:15-15:30 Carolin Antos: Engineering the concept of set in practice - a case for concept pluralism?
15:30-15:45 Break
15:45-17:00 Stewart Shapiro: Semantic indeterminacy, concept sharpening, set theories

Abstracts

Carolin Antos: Engineering the concept of set in practice - a case for concept pluralism?

Engineering the concept of set often involves meta-mathematical or philosophical discussions such as the foundational debate at the beginning of the 20th century or, more recently, the universe/multiverse debate in the philosophy of set theory. However one can also consider (at least part of) set-theoretic practice as a constant engineering process of the concept of set.
In this talk I would like to investigate if this practice gives rise to concept pluralism for the concept of set (as it arguably does for the concept of collection). To this end, I will connect the debate about conceptual engineering with the notion of concept pluralism that is discussed in philosophy of science. I argue that there are at least two theoretical uses the concept of set has, connected to Neil Barton's schematic and directed conception of set, and I will discuss this on the basis of the case of choichless large cardinals.

Neil Barton: Engineering Set-Theoretic Concepts

In this talk I'll present a main argument of a short book I'm working on entitled Engineering Set-Theoretic Concepts (I'm interested in comments on the draft, so please get in touch if you'd like to see it once ready). I'll first note that conceptual engineering has formed a part of set-theoretic activity since its inception as a mainstream area of mathematical research, and that the development of the iterative (and other) conceptions of set was in part responding to inconsistency in the naive set-concept. I'll then argue that whilst the iterative conception can be taken to be a consistent concept in its own right, it is deficient in various ways (in particular, it fails to tell us enough about the nature of infinite sets). Contemporary set theory, I'll argue, has now moved to a maximal iterative conception of set, and this conception is inconsistent. Many contemporary accounts of the ontology underlying set-theoretic practice should be conceived of as attempts to engineer consistent conceptions of the maximal iterative concept of set. I'll explain two such conceptions, the directed and schematic iterative conceptions of set. I'll tentatively conclude that discussion in the philosophy of set theory should focus less on the vexed and seemingly intractable issue of ontology, and instead concern itself more with the (nonetheless difficult) question of the relative theoretical virtues of alternative conceptions.

Tim Button: MOON theory: Mathematical Objects with Ontological Neutrality

The iterative notion of set starts with a simple, coherent story, and yields a paradise of mathematical objects, which “provides a court of final appeal for questions of mathematical existence and proof”. But it does not present an attractive mathematical ontology: it seems daft to say that every mathematical object is “really” some (pure) set. My goal, in this paper, is to explain how we can inhabit the set-theorist’s paradise of mathematical objects whilst remaining ontologically neutral. I start by considering stories with this shape: (1) Gizmos are found in stages; every gizmo is found at some stage. (2) Each gizmo reifies (some fixed number of) relations (or functions) which are defined only over earlier-found gizmos. (3) Every gizmo has (exactly one) colour; same-coloured gizmos reify relations in the same way; samecoloured gizmos are identical iff they reify the same relations. Such a story can be told about (iterative) sets: they are monochromatic gizmos which reify one-place properties. But we can also tell such stories about gizmos other than sets. By tidying up the general idea of such stories, I arrive at the notion of a MOON theory (for Mathematical Objects with Ontological Neutrality). With weak assumptions, I obtain a metatheorem: all MOON theories are synonymous. Consequently, they are (all) synonymous with a theory which articulates the iterative notion of set (LT+). So: all MOON theories (can) deliver the set theorist’s paradise of mathematical objects. But, since different MOON theories have different (apparent) ontologies, we attain ontological neutrality. My metatheorem generalizes some of my work on Level Theory. It also delivers a partial realization of Conway’s “Mathematician’s Liberation Movement”.

Herman Cappelen and Øystein Linnebo: Engineering the concept of collection: introductory remarks

The history of mathematics and philosophy have seen many different concepts of collection: a combinatorial set (understood as a gathering into one of previously available objects), a logical class (understood as defined by its membership condition, not by its members), a mereological sum, etc. My introductory remarks discuss some questions that this observation raises. What concepts of collection do we have? Which, if any, of these concepts should we use? Or should we “(re-)engineer” one or more concepts of collection to produce concepts that are more fit for purpose? I explain how we appear to need two importantly different concepts of collection: combinatorial sets (as on the famous iterative conception) and logical classes (cf. Parsons 1974, Maddy 1983, Linnebo 2006). The former is highly natural and well understood. Although the latter is less well understood, I argue that it too admits of a highly natural development.

Laura Crosilla: On Weyl’s predicative concept of set

A key component of the early 20th century literature on predicativity are variants of the traditional logical concept of set, according to which a set is the extension of a concept. In the first chapter of Das Kontinuum (1918), Hermann Weyl carefully spells out a new step-by-step construction of sets as extensions of predicative properties of the natural numbers, with the purpose of providing a strong and lasting foundation for mathematical analysis (and beyond). Weyl clearly contrasts his own concept of set with a quasi-combinatorial concept of set, which he finds wanting when working with infinite sets. It is remarkable that in Das Kontinuum Weyl deliberately moves away from a set-theoretic foundation of mathematics, which was instead the context of his Habilitation lecture of 1910. Weyl’s predicative concept of set and his predicative analysis have had lasting impact on mathematical logic and constructive mathematics. Arguably, a variant of a predicative concept of set as extension of a predicative property is also at the heart of some contemporary constructive type theories, which are increasingly popular due to their computational applications. In this talk, I argue that predicativism and Weyl’s changing positions on the foundations of mathematics are significant examples that are bound to enrich the contemporary debate on concept engineering in mathematics.

Kentaro Fujimoto: Plural, infinity, and impredicativity

Plural logic receives increasing attention and popularity. It counts plural terms among the irreducible basic vocabulary of logic that are of a distinct kind from singular terms, and allows quantification into plural term position. Advocates of plural logic often appeal to two benefits: namely, plural logic adequately formalizes plural discourse in English and is ontologically innocent. In this talk, I examine the legitimacy and necessity of plural logic and compare it with several alternative theories from philosophical, linguistic, and mathematical perspectives. Then I will argue that the two alleged benefits of plural logic do not necessarily endorse it. This is a work in progress.

Luca Incurvati: Engineering the concept of set and engineering the concept of objectified property

I will start by clarifying the extent to which the defence of the iterative conception in Incurvati 2020 is compatible with pluralism. The idea is that some conceptions are better than others for certain goals. The approach is functionalist about concepts: sharpenings of concepts are selected on the basis of how well they fullfill a certain function. I will then move on to discuss the case of objectified properties. I will again start from a functionalist approach and take as a starting point the expressive function of objectified-property talk. I will then report work in progress on an inferential deflationist theory of objectified properties, which is motivated by the functionalist approach and takes the meaning of objectified-property talk to be completely explained in terms of its inferential relation to property talk. I will discuss formal and philosophical aspects of the theory, in particular its relationship with Maddy's work on classes and the question of realism about objectified properties.

Stewart Shapiro: Engineering the concept of set and engineering the concept of objectified property

Friedrich Waismann once suggested that mathematical concepts are not subject to open-texture; they are “closed”. In other work, I have highlighted some traditional mathematical notions that were, at one time, open-textured. One of them is the notion of “polyhedron” following the history sketched in Lakatos’s Proofs and Refutations. Another case is computability, which has now been sharpened into a plausibly closed notion. There are also some mathematical notions that have longstanding, intuitive principles underlying them, principles that later proved to be inconsistent with each other, sometimes when the notion is applied to cases not considered previously (in which case it it perhaps an instance of open-texture). One examples is “same size”, which is or was governed by the part whole principle (one of Euclid’s Common Notions) and the one-one principle, now called “Hume’s Principle”. Another is the notion of continuity. The purpose of this talk is to explore the notion of “set” and other related (perhaps once identical) notions like class, totality, and the like. We tentatively put forward the thesis that this notion, too, is or was subject to open-texture (or something like it) and could be (and has been) sharpened in various ways. This raises some questions concerning what the purposes of a (sharpened) theory of sets are to be. And, in that context, the role of trying to give non-ad-hoc explanations or answers to various questions.

The workshop is organized within the Infinity and Intensionality project, jointly with ConceptLab.

Organizers

Neil Barton, Laura Crosilla and Øystein Linnebo

Communicating with AI Workshop

Arranged by ConceptLab, New Frontiers of Speech and AI&Humanities-Lab@HKU

Time and place: June 19, 2022 9:00 AM–June 20, 2022 4:15 PM, Georg Morgenstiernes Hus, room 452

Speakers

Herman Cappelen (HKU)
Josh Dever (Texas-Austin)
Gabe Dupre (Keele)
Gabbrielle Johnson (Claremont McKenna)
Fintan Mallory (Oslo)
Matthew McKeever (ConceptLab)
Tristram McPherson (Ohio State)
Eliot Michaelson (KCL)
Raphael Milliere (Columbia)
David Plunkett (Dartmouth)
Gurpreet Rattan (Toronto)
Mona Simion (Glasgow)
Rachel Sterken (HKU)

Program

Sunday, June 19th, 2022

9:00-10:15 Rachel Sterken, Eliot Michaelson and Jessica Pepp - The Alignment Problem in Human-AI Communication
10:15-11:30 Fintan Mallory - What Do Word Embeddings ‘Mean’?
11:30-11:45 Break
11:45-13:00 Raphael Milliere - Grammatical Competence and Artificial Intelligence
13:00-14:15 Lunch
14:15-15:30 Gabe Dupre and Gabbrielle Johnson - Uncanny Performance, Divergent Competence: Biases as Principled Barriers to Human-Machine Communication
15:30-15:45 Break
15:45-17:00 Gurpreet Rattan - Egocentric Content and Understanding Alien AI
18:30 Dinner

Monday, June 20th, 2022

9:00-10:15 Tristram McPherson and David Plunkett - Strong AI and the Foundations of Ethics
10:15-11:30 Matthew McKeever - AI and Illocutions
11:30-11:45 Break
11:45-13:00 Mona Simion - Talking to Social Robots
13:00-14:00 Lunch
14:00-15:15 Herman Cappelen and Joshua Dever - AI and the Commodification of Meaning and Communication

2021

Critical views of Infinity

Time: June 15, 2021–June 16, 2021

The focus of the workshop are views of infinity that are critical of actual infinity. The literature presents us with a heterogeneous constellation of criticism of what is often called “Cantorian infinity”. This workshop will explore and compare a number of approaches to potentialism stemming from the history and contemporary mathematical practice. By comparing a number of approaches, we hope to better understand what are the perceived difficulties with actual infinity and which proposals have been put forth to overcome them. These include, for example, predicativist and constructivist approaches to mathematics and potentialist views of the set-theoretic universe in philosophy of mathematics.

The workshop is part of the project Infinity in Mathematics: a Philosophical Analysis of Critical Views of Infinity. This project receives funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 838445.

Speakers:

Thierry Coquand (University of Gothenburg)
Laura Crosilla (University of Oslo)
Mirja Hartimo (University of Helsinki)
Reinhard Kahle (Tübingen University)
Øystein Linnebo (University of Oslo)
Dag Normann (University of Oslo)
Michael Rathjen (University of Leeds)
Sam Sanders (Ruhr-Universität Bochum)
Wilfried Sieg (Carnegie Mellon University)

Schedule

Tuesday 15 of June 2021 (Oslo time)

13:55 Opening
14:00 -- 15:10 Mirja Hartimo: Husserl on foundations: Top-down and bottom-up
10 minutes break
15:20 -- 16:30 Øystein Linnebo: Potentialism and Critical Plural Logic
15 minutes Break
16:45 -- 17:55 Dag Normann and Sam Sanders: Countability - the simplest kind of infinity?
10 minutes break
18:05 -- 19:15 Wilfried Sieg: Methodological Frames: Mathematical structuralism and proof theory

Wednesday 16 of June 2021

14:00 -- 15:10 Thierry Coquand: Point-Free Topology and Sheaf Models
10 minutes break
15:20 -- 16:30 Michael Rathjen: Predicativity and the nature of function spaces
15 minutes Break
16:45 -- 17:55 Reinhard Kahle: Cantor’s Paradise
10 minutes break
18:05 -- 19:15 Laura Crosilla: Cantor’s Paradise and the Forbidden Fruit

Registration: The workshop will take place via Zoom.
Contact Laura.Crosilla @ ifikk.uio.no for a Zoom-invite.

Abstracts

Thierry Coquand

Title: Point-Free Topology and Sheaf Models

The question whether or not a given collection of mathematical objects should be considered as an actual, completed totality, or should only be considered as a potential, open collection, occurs often in constructive mathematics. One can for instance compare the collection of real numbers, presented as a set of Cauchy sequences in Bishop's book, to the notion of choice sequences in Brouwer.
In algebra, a similar question arises for the collection of all algebraic numbers (or, more generally, for the algebraic closure of a given field).
H. Edwards opposes in this way Kronecker and Dedekind's approach of the theory of algebraic curves:
The necessity of using an algebraically closed ground field introduced –and has perpetuated for 110 years- a fundamentally transcendental construction at the foundation of the theory of algebraic curves. Kronecker's approach, which calls for adjoining new constants algebraically as they are needed, is much more consonant with the nature of the subject ("Mathematical ideas, ideals, and ideology", 1992).
We will try to revisit in this talk this question, in the light of recent works on point-free topology and sheaf models.

Laura Crosilla

Title: Cantor’s Paradise and the Forbidden Fruit

In this talk, I discuss potentialist views of infinity that highlight a key foundational role for the natural numbers within mathematics. My focus are aspects of the foundational reflections by mathematicians Henri Poincaré, Hermann Weyl and Errett Bishop. One of Poincaré’s characterizations of predicativity focuses on invariant definitions and is bound up with his potentialist view of infinity. For Weyl (1918) the sequence of the natural numbers is an ultimate foundation of mathematical thought over which ``a realm of new ideal objects, of sets and functional connections is erected by means of the mathematical process’’. Bishop highlights the pivotal role of the set of integers for uncovering the computational content of mathematics. I single out affinities between these views and argue for the fruitfulness of an analysis of critical views of infinity.

Mirja Hartimo

Title: Husserl on foundations: Top-down and bottom-up

In his writings on theoretical approach to the world, Husserl distinguishes two approaches, both of which can be given a ”precise mathematical sense.” These approaches are i) a top-down approach, which reveals the ”apriori sctructure of the infinite world” and ii) a bottom-up approach, which builds on judgments about intuited ”morphological realities” and their ”morphological types” and is finitely verifiable (esp. Husserl 2012, 286-290). In her talk, after having elaborated on these two approaches and their relationship to each other, Hartimo will suggest relating them to an extensional, structuralist approach and an intensional approach. The paper will then explain what Husserl has to say about the exact nature of the latter approach and how Husserl seems to think these two approaches can be unified.

Reinhard Kahle

Title: Cantor's Paradise

We review some historical examples which convinced the mathematical community that Cantorian Set Theory is a paradise. We also discuss how these examples resist philosophical onslaughts.

Øystein Linnebo

Title: Potentialism and Critical Plural Logic

Potentialism is the view that certain types of entity are successively generated, in such a way that it is impossible to complete the process of generation. What is the correct logic for reasoning about all entities of some such type? Under some plausible assumptions, classical first-order logic has been shown to remain valid, whereas the traditional logic of plurals needs to be restricted. Here I seek to answer the open question of what is the correct plural logic for reasoning about such domains. The answer takes the form of a critical plural logic. An unexpected benefit of this new logic is that it paves the way for an alternative analysis of potentialism, which is simpler and more user-friendly than the extant modal analysis.

Michael Rathjen

Title: Predicativity and the nature of function spaces

Function sets are crucial to the development of constructive mathematics. Classically, however, they entail the full force of impredicativity: the Power Set Axiom. Their acceptance and rationale in constructive mathematics has been an important topic and concern for central constructivist thinkers such as Brouwer, Myhill, Bishop, Goodman, Dummett, Feferman, Martin-Löf.
In the talk, I shall survey some of their views and struggles, and then try to use tools and results from mathematical logic to shed more light on the issue.

Dag Normann and Sam Sanders

Title: Countability - the simplest kind of infinity?

A set is enumerable if it is the range of a function defined on the set of positive integers. A set is countable if there is an injection (or bijection) from the set to the set of positive integers. In set theory, as developed since the late 19th century, these concepts are equivalent.
However, in rather strong formal theories suitable for Reverse Mathematics the concepts are not equivalent. Enumerable subsets of the reals can be treated as a part of Second-Order Arithmetic (SOA), while countable sets can only be analysed properly in third-order arithmetic, e.g. in Kohlenbach’s higher order Reverse Mathematics.
In this talk we will discuss the complexity of the statement that all countable subsets of the reals are enumerable and survey some classical theorems where the two concepts cannot be interchanged without the introduction of axioms that genuinely goes beyond SOA. We will also touch upon the necessary computational complexity of a functional witnessing the fact that all countable sets of reals are enumerable.
We discuss the foundational and philosophical implications, including a new twist on predicative mathematics.

Wilfried Sieg

Title: Methodological Frames: Mathematical structuralism and proof theory

Mathematical structuralism is deeply connected with Hilbert and Bernays’ proof theory and their programmatic aim to ensure the consistency of mathematics. That goal was to be reached on the sole basis of finitist mathematics. Gödel’s second incompleteness theorem forced a step from absolute finitist to relative constructivist proof theoretic reductions. The mathematical step was accompanied by philosophical arguments for the special nature of the grounding constructivist frames. Against this background, I examine Bernays’ reflections on proof theoretic reductions – from the mid-1930s to the late 1950s and beyond – that are focused on narrowly arithmetic features of frames.

I propose a more general characterization of frames that has ontological and epistemological significance. It is rooted in the internal structure of mathematical objects and is given in terms of accessibility: domains of objects are accessible if their elements are inductively generated; principles for such domains are accessible if they are grounded in our understanding of the generating processes. The accessible principles of inductive proof and recursive definition determine the generated domains uniquely up to a canonical isomorphism. The determinism of the inductive generation allows us to refer to the objects of an accessible domain; at the same time, the canonicity of the isomorphism justifies an “indifference to identification”.

Organizer

Laura Crosilla and Øystein Linnebo

2021

Varieties of Potentialism

Time and place: Sep. 23, 2020 12:00 PM–6:40 PM, Zoom

Potentialism in mathematics is, roughly, the view that a mathematical universe is never fully completed because there always could be more objects of the relevant kind to consider. In particular, set-theoretic potentialism has it that the set-theoretic universe is never fully completed, since for any circumscribed totality of sets it seems there could have been further sets, and thus a larger totality of sets to take into account.

Contemporary exploration of potentialism has revealed that there are several important theoretical choices that potentialists face when formulating their view. This gives rise to different varieties of potentialism. This mini-workshop will explore issues and disagreements that could arise between them. In particular, we are interested in the following issues:

The question of the correct modal logic for the potentialist (S4, S4.2 or S4.3 are common candidates). Also, should the logic be classical, intuitionistic, or something else?
branching vs. non-branching possibility (either for set-theoretic hierarchies or other mathematical structures)
whether translations between the modal, potentialist language and the non-modal, actualist language are desirable at all
in what way answers to the previous issues/questions depend on how the relevant modality is understood

Program (time displayed in CEST)

12.00-12.10: Welcome and introduction
12:10-13.00: Sam Roberts (University of Konstanz) "Potentialism and ultimate V"
13.10-14.00: Joel David Hamkins (University of Oxford) "Modal Model Theory as Mathematical Potentialism"
14.00-14.30: Break
14.30-15.20: Hans Robin Solberg (University of Oxford) "Radical Potentialism"
15.30-16.20: Ethan Brauer (Lingnan University) "Intuitionism and Potentialism about Real Numbers"
16.20-16.50: Break
16.50-17.40: Stewart Shapiro (Ohio State University) and Øystein Linnebo (University of Oslo) "Choice sequences: a modal and classical analysis"
17.50-18.40: Laura Crosilla and Øystein Linnebo (University of Oslo) "Two kinds of potential domains: some logical and historical remarks"

Abstracts

Title: Potentialism and ultimate V"

Speaker: Sam Roberts (University of Konstanz)

Potentialism is the view that the universe of mathematics is inherently potential. It comes in two main flavours: height-potentialism and width-potentialism. It is often thought that these are two aspects of a broader phenomenon: that the universe of sets is potential in both ways. In this talk, I show that this thought is mistaken: height-potentialism and width-potentialism are inconsistent with one another. In particular, I will argue that height-potentialism implies the existence of an ultimate background universe of sets—an ultimate V—to which no new sets can be added by forcing and in which every set-theoretic statement is either determinately true or determinately false. This directly contradicts the core claim of width-potentialism that there are no such universes.

Title: Modal model theory as mathematical potentialism

Speaker: Joel David Hamkins, Oxford

I shall introduce and describe the subject of modal model theory, in which one studies a mathematical structure within a class of similar structures under an extension concept, giving rise to mathematically natural notions of possibility and necessity, a form of mathematical potentialism. We study the class of all graphs, or all groups, all fields, all orders, or what have you; a natural case is the class $\text{Mod}(T)$ of all models of a fixed first-order theory $T$. In this talk, I shall describe some of the resulting elementary theory, such as the fact that the $\mathcal{L}$ theory of a structure determines a robust fragment of its modal theory, but not all of it. The class of graphs illustrates the remarkable power of the modal vocabulary, for the modal language of graph theory can express connectedness, colorability, finiteness, countability, size continuum, size $\aleph_1$, $\aleph_2$, $\aleph_\omega$, $\beth_\omega$, first $\beth$-fixed point, first $\beth$-hyper-fixed-point and much more. When augmented with the actuality operator @, modal graph theory becomes fully bi-interpretable with truth in the set-theoretic universe. This is joint work with Wojciech Wołoszyn.

Title: Intuitionism and Potentialism about Real Numbers

Speaker: Ethan Brauer, Lingnan

In intuitionistic analysis, real numbers are apprehended via real number generators, which are potentially infinite sequences of rational numbers satisfying the Cauchy convergence criterion. Using a modal theory of free choice sequences I will present a modal theory of real number generators with a classical background theory. Many concepts from intuitionism are nicely captured in this setting, and characteristic results from intuitionistic analysis have analogues in this modal theory. For instance, it is not the case that every real number is determinately rational or irrational; the natural order on real numbers is not linear; and there exists a bounded monotone sequence of rationals which is not necessarily Cauchy. Finally, I introduce a notion of sharp discontinuity and show there is no function on the reals that is sharply discontinuous.

Title: Two kinds of potential domains: some logical and historical remarks

Speakers: Laura Crosilla and Øystein Linnebo, Oslo

Potentialists defend a distinction between actual and merely potential domains. We defend the philosophical and mathematical importance of a less familiar distinction that applies to the merely potential domains: those that are predetermined and those that are not. This is a question of whether we have clearly circumscribed the possibilities that we wish to consider. For example, a potentialist about the natural numbers can take the possibilities for generating natural numbers to be predetermined. The transition from Weyl 1918 to 1921 will be used to illustrate the distinction. We also make some remarks about how generalizations over the two different kinds of merely potential domains can be understood.

Organizer

Øystein Linnebo and Robin Solberg

Taking Stock Workshop (online)

Time: June 16, 2020 9:30 AM–5:00 PM

Members, friends and would-be visitors of and to ConceptLab give short talks and take stock of their work. This year's workshop will be an online event, on Zoom (details tba).

Format: 15 minute talks, 7 minute Q&A. 10 minute breaks between every second slot.

Schedule in Norwegian time (UTC +2). For BST, subtract 1 hour. For EDT, subtract 6 hours.

0930 Welcome
0935 Camilla Serck-Hanssen
1000 Rachel Sterken
1025 Herman Cappelen
1100 Andreas Carlsson
1125 Dragana Bozin
Lunch break
1300 Sam Roberts "Potentialism in mathematics"
1325 Laura Crosilla "On the concept of set"
1400 Joey Pollock "Content, disagreement, and verbal disputes"
1425 Øystein Linnebo "Should I join the revolution? Some thoughts about strict vs. liberal potentialism"
Break
1515 Mirela Fuš "Engineering generic judgments"
1540 David Plunkett
1615 Matthew Shields "Practices of Samesaying"
1640 Eleonore Neufeld "Pornography, Discourse, and Desires"

Finished at ca 1700.

In the process of being reorganized Workshop Conceptual Engineering: The Role and Nature of Functions

Time and place: June 12, 2020–June 13, 2020, University of Oslo

This event was scheduled as an ordinary workshop with physical presence before the outbreak of the Corona virus. It is currently being reorganized as an online event. Updated information will appear here when the reorganization is completed.

Topic: The following claim underlies much work in conceptual engineering, genealogy, and related fields:

CLAIM: "Concepts perform functions (or have jobs)”.

Question: can CLAIM be made true and philosophically significant? If no, why not? If yes, what does ‘concept’ mean, what does ‘function’ mean, and what’s the philosophical significance of the CLAIM?

CFP (external link)

Speakers:

Tim Sundell (University of Kentucky)
Jennifer Nado (University of Hong Kong)
Amie Thomasson (Dartmouth College)
Mona Simion (University of Glasgow)
Chris Kelp (University of Glasgow)
Matthieu Queloz (University of Oxford)
Justin Garson (Hunter College)
David Plunkett (Dartmouth College)
Herman Cappelen (University of Oslo)

Organizer

Herman Cappelen and David Plunkett

2019

Predicativity and the notions of stability and invariance

Time and place: Nov. 27, 2019 12:15 PM–1:45 PM, GM 452, University of Oslo

Organizer

Øystein Linnebo

Workshop: Conceptual analysis, conceptual engineering and experimental philosophy

Time and place: Nov. 15, 2019–Nov. 16, 2019, University of Zurich

Collaboration between ConceptLab and University of Zurich.

Talk by Sorin Bangu

Time and place: Nov. 6, 2019 2:15 PM–4:00 PM, GM 652

Workshop: Self-blame and Moral Responsibility

ConceptLab and the Center for the Study of Mind in Nature

Time and place: Sep. 20, 2019–Sep. 21, 2019, Georg Morgenstiernes hus 652, University of Oslo

Organizer: Andreas Brekke Carlsson.

The workshop will consist of 25-minute presentations, followed by 35-minute Q&A-sessions. The papers on which the presentations are based will be made available. Please contact Andreas if you would like to attend and have a look at the papers.

20th of September

9.30 – 10.30. Justin D’Arms and Daniel Jacobson: The Motivational Theory of Guilt (and Responsibility)
10.30 – 10.45 Break
10.45- 11- 45. Michelle Mason: Shame as a Self-reactive Attitude
11.45- 12.00: Break
12.00- 13.00 Douglas Portmore: A Comprehensive Account of Blame: Self-Blame, Non-Moral Blame, and Blame for the Non-Agential
13.00-14.00 Lunch
14.00-15.00: Derk Pereboom: Forward- looking Self- Blame
15.00 - 15.15: Break
15.15- 16.15: Dana Nelkin: How Much to Blame? An Asymmetry Between the Norms of Self-Blame and Other-Blame
16.15- 16.30. Break
16.30- 17.30. David Shoemaker: The Trials and Tribulations of Tom Brady: Self-blame, Self-Talk, Self-Flagellation

21st of September

10.00 - 11.00. Coleen Macnamara: Guilt, Desert, Fittingness, and the Good.
11.00 - 11.15: Break
11.15 - 12.15. Michael McKenna: Guilt and Self-blame
12.15 - 12.30: Break
12.30 - 13.30. Andreas Brekke Carlsson: Guilt and Blameworthiness over Time
13.30 - 14.30: Lunch
14.30 - 15.30: Randolph Clarke and Piers Rawling: Reason to Feel Guilty
15.30 - 15.45: Break
15.45 - 16.45: Krista Thomason: Blame for Recalcitrant Emotions

In View of Mathematical Thought and its Objects

Time and place: Aug. 10, 2019 10:00 AM–Aug. 11, 2019 5:45 PM, GM 652, Universitetet i Oslo

Program

Saturday 10 August

10:00 -11:30 Opening Remarks

Dagfinn Føllesdal Charles: sixty years of friendship and discussion of the philosophy of mathematics, in particular centering on mathematical intuition

Michael Friedman Pure Natural Science and the Schematism: Learning from Charles

11:30-11:45 break

11:45-13:15

MTO Chapter 1

Michael Glanzberg: Objects and Logic

13:15- 14:30 Lunch

14:30-16:00

MTO Chapter 2

Mirja Hartimo: Structuralism and Husserl

16:00-16:15 Break

16:15-17:45

MTO Chapter 5

Frode Kjosavik: Mathematical Intuition and Intuitive Knowledge

Sunday 11 August

10:00-11:30

MTO Chapter 6

Øystein Linnebo: Ordinal Vs Cardinal Aspects of the Natural Numbers

11:30 -11:45 break

11:45-13:15

MTO Chapter 7

Ofra Rechter: On the Kantian Pedigree of Finitism

13:15-14:30 Lunch

14:30-16:00

MTO Chapter 8

Charles Parsons: Mathematical Induction, Chapter 8 Revisited

16:00-16:15 break

16:15-17:45 In View of MTO Round Table Discussion

Organizer

Øystein Linnebo and Ofra Rechter (Tel Aviv University)

Workshop on Difficulties in Communicating Online

Time and place: June 28, 2019 9:00 AM–6:00 PM, University of Oslo

11:15 Torfinn Huvenes (Umea) (with H. Cappelen) On hedging
12:30 Lunch
13:30 Eliot Michaelson (KCL) #Influencers
14:45 Jessica Pepp (Uppsala) TBA
18:30 Dinner

Organizer

Eliot Michaelson, Jessica Pepp and Rachel Sterken

Workshop on Speech Act Engineering

Time and place: June 27, 2019 9:00 AM–6:00 PM, University of Oslo
Speech Act Engineering

11:15 Jessica Keiser (Leeds) TBA
12:30 Lunch
13:15 Elmar Unnsteinsson (Dublin/Iceland) Reengineering Reference
14 30 Break
14:45 Dan Harris (CUNY) How Should We Taxonomize Speech Acts?
18:30 Dinner

Organizer

Eliot Michaelson, Jessica Pepp and Rachel Sterken

One day workshop - ConceptLab taking stock

Time and place: June 6, 2019 10:00 AM–3:30 PM, Georg Morgenstiernes hus 652, University of Oslo

Members of and visitors to ConceptLab give talks and take stock of their work.

Schedule

10 AM. Herman Cappelen
10:20 AM. Øystein Linnebo
10:40 AM. Camilla Serck-Hanssen and Andreas Carlsson
11 AM. Rachel Sterken
Break
11:30 AM. Josh Dever
11:50 AM. Andrew Peet
12:10 PM. Vera Flocke
12:30 PM. Sam Roberts
Lunch
2 PM. Peter Fritz
2:20 PM. Natalia Waights Hickman
2:40 PM. Ethan Brauer
3 PM. Bashshar Haydar

Workshop: Linguistic Meaning: Metaphysics, Epistemology, and Ethics, in Oxford

Time and place: Apr. 25, 2019–Apr. 27, 2019, Oxford
Speakers TBA

Linguistic Meaning: Metaphysics, Epistemology and Ethics Philosophy Conference

Time and place: Apr. 25, 2019–Apr. 27, 2019, The Queen’s College (Shulman Auditorium) High Street Oxford OX1 4AW. The Queen’s College, University of Oxford, in collaboration with ConceptLab, Oslo.

We invite submissions of long abstracts (1000-1500 words) for presentation at a conference on three facets of linguistic meaning:

1. Metaphysics of meaning and metasemantics
2. Epistemology of meaning and linguistic understanding
3. Ethical and ideological dimensions of meaning, and conceptual engineering.

Submissions may fall within any of the three strands; we especially welcome contributions that address interactions between two or more. Papers should be suitable for 45 minute presentation.

This conference aims to bring new work in the metaphysics, epistemology and ethics of meaning into dialogue, revisiting some long-standing and foundational questions in light of the resurgence and development of the idea that a philosopher’s task is to modify aspects of her language for social or theoretical ends, not merely to describe it. An overarching theme of the conference is the question how speakers are related, practically and epistemically, to the languages at their command, and in particular to facts about meaning and conceptual content. Submissions may therefore address the following or related questions:

What is linguistic meaning? How is it determined? Can individuals or communities of speakers change it at will?
How does semantic change occur, and what does it entail?
What is the relationship between meaning and social or natural kinds? Are these amenable to deliberate reform? If so, how?
Is a speaker’s language independent of her linguistic competence?
Is meaning in any sense mind-dependent? How does linguistic meaning relate to thought and mental representation?
In what sense, if any, do speakers have knowledge of language?
In what sense, if any, is linguistic knowledge or understanding required for communication?
Is linguistic competence intrinsically or distinctively rational? If so, how?
Is linguistic understanding knowledge-that or knowledge-how? If the latter, might it nevertheless be propositional knowledge, as intellectualists contend?
Is linguistic/conceptual ethics well motivated, theoretically and/or practically?
Is the viability of linguistic/conceptual ethics compatible with semantic externalism?
What makes one meaning/concept better than another? Are certain meanings/concepts more eligible, or fitting for use, than others?

Invited Speakers

Ian Rumfitt (Oxford)
Imogen Dickie (Toronto)
Guy Longworth (Warwick)
Rae Langton (Cambridge)
John Collins (UEA)
Herman Cappelen (Oslo)

Organizer

Herman Cappelen , Joey Pollock, Andrew Peet and Natalia Waights Hickman (Oxford)

Workshop on Mutual Understanding

Time and place: Mar. 29, 2019 11:00 AM–Mar. 30, 2019 5:30 PM, Department of Philosophy, Yale University

Department of Philosophy, Yale University

Friday, March 29, Connecticut Hall, Faculty Room

11AM–12:15PM Understanding in the Natural and Social Sciences: Kareem Khalifa, Middlebury
12:15–1:15 Lunch
1:15–2:30 The Many Ways of Understanding Others, John Bengson, UW-Madison
2:30–3:45 Scaling the Epistemic Wall in Moral Decision-making, Molly Crockett, Yale
4:00–5:15 The Role of Empathy in Linguistic Understanding, Herman Cappelen, Oslo & St Andrews
5:15–6:30 Bad at Empathy, Paul Bloom, Yale
7:30 Party at Laurie Paul’s house

Saturday, March 30, Connecticut Hall, Faculty Room

10AM–11:15 Arrogance and Misunderstanding What Matters, Michael Patrick Lynch, UConn
11:15–12:30PM Lunch
12:30–1:30 Distinct Forms of Explanatory Understanding Support Abstraction and Mental Simulation, Tania Lombrozo, Princeton
1:30–2:45 Capturing the Character of Others,David Pizarro, Cornell
3:00–4:15 Humanistic Understanding, Michael Strevens, NYU
4:15–5:30 How ”Inappropriate" Affect Signals Emotional, Propensities: The Case of Agent-Regret, Shaun Nichols, Arizona

Formal concepts mini-workshop

Time and place: Mar. 15, 2019 11:00 AM–4:00 PM, GM 652, University of Oslo

Schedule

11-12.15 Sam Roberts “Sets as Structures”
12.15-13.15 Lunch break
13.15-14.30 Alexander Roberts “Necessity in the Highest Degree”
14.45-16 Stewart Shapiro “Making Truth safe for Intuitionists”

Abstracts

“Sets as Structures”, Sam Roberts

According to standard (ante rem) structuralism, sets are places in a certain structure. It follows that sets have a number of unwelcome features. For example, sets seem to exhibit an asymmetric dependency on their elements and the totality of all sets seems to be inherently potential. But the structuralist must deny this. In this talk, I propose a new form of structuralism. According to it, sets are not places in a certain structure, they are structures themselves. I show how this view overcomes the above problems.

“Necessity in the Highest Degree”, Alexander Roberts

In Naming and Necessity, Kripke was careful not to prejudge which notion of necessity was ‘necessity in the highest degree’, and left it as an open question. In this talk, I will sharpen Kripke’s open question and make significant progress towards answering it. The investigation will involve a study of how different ‘objective’ modalities, such as physical necessity, interact with one another and behave. By studying such interactions, there is much insight to be gained into which notions of necessity are suited to be necessity in the highest degree.

“Making Truth safe for Intuitionists”, Stewart Shapiro

We consider a handful of solutions to the liar paradox which admit a naive truth predicate and employ a non-classical logic, and which include a proposal for classical recapture. Classical recapture is essentially the property that the paradox solvent (in this case, the non-classical interpretation of the connectives) only affects the portion of the language including the truth predicate – so that the connectives can be interpreted classically in sentences in which the truth predicate does not occur.

We consider a variation on this theme where the logic to be recaptured is not classical but rather intuitionist logic, and consider the extent to which these handful of solutions to the liar admit of intuitionist recapture by sketching potential ways of altering their various methods for classical recapture to suit an intuitionist framework.

Workshop on War Crime

Time and place: Mar. 10, 2019 11:15 AM–5:00 PM, GM 652, University of Oslo
Workshop on "War Crimes" by Matthew Talbert and Jessica Wolfendale

11.15- 12. Introduction by Matthew Talbert and Jessica Wolfendale
12.00 Coffee
12. 15- 13. 00 Comment by Andreas Carlsson (Oslo)
13-14.30 Lunch
14.30-15.15. Comments by Anneli Jefferson (Birmingham)
15.15- 16.00 Comments by Benjamin Matheson (Stockholm)
16.00 Coffee
16. 15- 17 Comments by Lars Christie (Oslo)

The Philosophy of Online Speech Acts and Communication

Time and place: Feb. 7, 2019 1:30 PM–Feb. 8, 2019 5:00 PM, Department of Philosophy, Uppsala University

Description: Language use has changed a lot with the advent of ICT media. Philosophers of language have yet to explore whether these changes demand adjustments to traditional frameworks. Do they? And if so, what kind of adjustments? One possibility is that these changes have only brought about differences in scale, not in kind, and so don’t demand any fundamental changes to our theoretical approaches. Another possibility is that there are differences in scale and/or in kind that do demand big changes. Or maybe it is something in between. If it is time to revisit fundamental approaches, how much revision is required? Which phenomena might require new approaches? Is online communication more continuous with offline in terms of its basic nature, or is it moving towards a very different kind of thing?

Relatedly and more specifically, how well do actions, such as sharing, tweeting, liking, etc., fit into existing taxonomies of speech acts? What implications do they have for various theories of speech acts? Has social media changed the taxonomy of speech acts and the nature of those acts to such an extent as to require wholesale revision of speech act theory?

Department of Philosophy, Uppsala University

Organised by Eliot Michelson (KCL), Jessica Pepp (Uppsala) and Rachel Sterken (Oslo)

Sponsored by an NFR SAMKUL Network grant

Thursday 7 February

13.30-13.45 opening
13.45-15.00 Torfinn Huvenes (Umeå)
15.15-16.30 Nat Hansen (Reading)

Friday 8 February

11.15-12.30 Gunnar Bjornsson (Stockholm) (w Eliot Michaelson, Jessica Pepp and Rachel Sterken)
12.30-13.30 Lunch
13.30-14.45 Peter Pagin (Stockholm)
15-17.00 Panel Discussion: Jonas Åkerman (Stockholm), Jessica Keiser (ANU), Elmar Unnsteinsson (Iceland and Dublin), Åsa Wikkfors (Stockholm)
Friday evening dinner

Organizer

Rachel Sterken, Jessica Pepp and Eliot Michelson

Conceptual Engineering in the Ethics of War

Time and place: Jan. 11, 2019 9:00 AM–Jan. 12, 2019 5:00 PM, University of Oslo, GM 652

Friday 11th

13.15- 14.45. Wendy Salkin: Faceless Witnesses and the Frustration of Due Process
14.45-15. Coffee
15-16.30. Michael Robillard: The Ethics of Special Ops

Saturday 12th

9.30- 11.00. Lars Christie: The moral liability of innocent killers
11.00-11.15. Coffee
11.15-12.45. David Rodin: Authority and Determination-Relative Wrong
12.45-13.45 Lunch
13.45- 15.15: Susanne Burri: A Culpability Account of Liability to Defensive Harm
15.15- 15.30: Coffee
15.30- 17.00: Andreas Carlsson: Culpability, Liability and Desert
17.15- 17.30
17.30-19.00 Camilla Serck-Hanssen: Moral Equality of Combatants- a Kantian account

Organizer

Camilla Serck-Hanssen

2018

Workshop on Metasemantics

Time and place: Oct. 1, 2018–Oct. 2, 2018, At the University of Tokyo, in collaboration with ConceptLab

October 1

Robbie Williams: Radical Interpretation and Mental Reference Magnetism. Respondent: Josh Dever

Robbie Williams: From mental representation to linguistic representation.
Respondent: Brian Weatherson

Lunch

Anandi Hatangandi: ‘Semantic Supervenience and Haecceities’
Respondent: Max Deutsch

Seth Yalcin: "The Tension Between Compositionality and Convention”
Matti Eklund

October 2

Joey Pollock 'Content individuation, conceptual engineering and social inequality'
Respondent: Ishani Maitra

Sara Sawyer: Thought and Talk
Respondent: Herman Cappelen

Lunch

Derek Ball: “Trying to Mean and Meaning”
Respondent: Rachel Sterken

Cian Dorr: tba
Respondent: Tim Sundell

The Foundations of Conceptual Engineering

New York Institute of Philosophy and University of Oslo’s Project ConceptLab present: The Foundations of Conceptual Engineering

Time and place: Sep. 14, 2018 9:00 AM–Sep. 15, 2018 5:30 PM, New York University, Department of Philosophy 5 Washington Place, New York, NY 10003

14 September

9.10–10.10 David Chalmers "What is Conceptual Engineering and What Should It Be?"
10.15-11.15 Matti Eklund "Radical Conceptual Engineering"
coffee
11.45-12.45 Sally Haslanger "Concepts, Capacities and Social Functions"
lunch
2pm-3pm Jared Riggs "Conceptual Engineers Shouldn’t Worry about Semantic Externalism"
3.05-4.05 Steffen Koch "The Externalist Challenge to Conceptual Engineering"
coffee
4.35-5.35 Laura Schroeter "Conceptual Engineering and Concept Identity"
5.40-6.40 Vera Flocke "The Metasemantics of Indefinite Extensibility"

15 September

9.30-10.30 Herman Cappelen "Conceptual Engineering vs Conceptual Activism: why conceptual change is incomprehensible and uncontrollable"
10.35-11.35 Amie Thomasson "Conceptual engineering: When do we need it? How can we do it?"
lunch
12.50-1.50 Alex Byrne "‘Gender’ Trouble"
1.55-2.55 Ari Koslow "Conceptual Bridge Building"
coffee
3.25-4.25 Edouard Machery TBA
4.30–5.30 Alexis Burgess and David Plunkett "The Relationship Between Conceptual Ethics and Conceptual Engineering"

Workshop on Salvatore Florio and Øystein Linnebo's manuscript The Many and the One: A Philosophical Study

Time and place: June 15, 2018–June 16, 2018, GM 652, University of Oslo

Workshop on Salvatore Florio and Øystein Linnebo's manuscript The Many and the One: A Philosophical Study (Oxford University Press)

The workshop is pre-read and by invitation only. If you are interested in attending, please contact oystein.linnebo@ifikk.uio.no

Philosophical Applications of Modal Logic

Time and place: June 13, 2018–June 14, 2018, GM 652, University of Oslo
Schedule:

Wednesday June 13:

09:30-11:00 Jessica Leech (KCL), Relative Necessity Extended
11:15-12:45 Sven Rosenkranz (Barcelona), Towards a logic for being in a position to know
13:30-15:00 Brian Rabern (Edinburgh), Toward a solution to the nesting problem for two-dimensionalism
15:15-16:45 Susanne Bobzien (Oxford), Intuitionism and the Modal Logic of Vagueness (joint work with Ian Rumfitt)

Thursday June 14:

09:30-11:00 Peter Fritz (Oslo), Possible Worlds in Higher-Order Logic
11:15-12:45 Wesley Holliday (Berkeley), From Worlds to Possibilities…and Back?
13:30-15:00 Øystein Linnebo (Oslo), Predicativism and potential infinity (joint work with Stewart Shapiro)
15:15-16:45 Stephan Leuenberger (Glasgow), Fragmentation and introspection in epistemic logic (joint work with Martin Smith)

Abstracts:

Jessica Leech (KCL), Relative Necessity Extended
One can fruitfully define various kinds of alethic necessity as relative, that is, as the logical consequences of a particular set of true propositions. For example, one might take the natural necessities to be what is logically necessary relative to the laws of nature. One merit of such an approach is that we can explain the commonality between different necessities; they are all relativizations of one and the same fundamental necessity. One might then ask: what about non-alethic (and epistemic) necessities? There is a sense in which epistemic, doxastic, legal, deontic, and other necessities are also necessities. But the relativist approach, in taking these to be the logical consequences of, say, known propositions, believed propositions, the laws of morality, etc., runs in to serious and familiar problems (that arise from the logic). In my talk, I assess various options for solving these problems, with a view to exploring whether a larger-scale unification of necessity – alethic and non-alethic – is possible (or desirable) for the relativist.

Sven Rosenkranz (Barcelona), Towards a logic for being in a position to know
My concern is with an epistemic logic governing the notion of being in a position to know. Such a logic is of independent interest. My own interest stems more specifically from my work on justification. According to the view I’ve defended elsewhere, p is propositionally justified iff one is in no position to know that one is in no position to know p. More recently, I have argued that p is doxastically justified iff one is in no position to know that one doesn’t know p – where a belief is justified iff it is held under circumstances under which p is doxastically justified in this sense. I will not here argue for these claims. Instead, I wish to explore the features that the underlying epistemic logic and semantics ought to have. After introducing principles of knowledge, and of being in a position to know, that should be acceptable to almost everyone, I suggest two non-standard principles governing these notions and provide a rationale for them. After highlighting a number of interesting theorems, I then proceed to argue that, just like knowledge-operators, operators for being in a position to know behave non-normally and create hyperintensional contexts, with well-known consequences for formal semantics. I make some suggestions of what shape a suitable semantic treatment should take, and dwell on some unresolved issues to which this treatment gives rise, and whose proper resolution bears on the larger project of characterising justification in the ways proposed.

Brian Rabern (Edinburgh), Toward a solution to the nesting problem for two-dimensionalism
Post-Kripkean theorising concerning modal epistemology accepts a misalignment between apriority and necessity. Two-dimensional semantics provides a framework in which to analyse the Kripkean phenomena of the contingent a priori and the necessary a posteriori. And, as the name suggests, it does so in terms of two “dimensions” of meaning or two levels of semantic value associated with any linguistic expression. But there is a problem concerning how these two levels compose and interact. In particular the problem concerns nested environments: environments where sentences are nested under both modal and epistemic operators (see Soames 2005, Dever 2007, and Forbes 2011). Soames, in fact, insists that nested environments pose the “chief technical problem” for two-dimensionalism. There is a general problem here for a multi-modal logic with operators for metaphysical necessity and epistemic necessity. In light of the contingent priori we face a dilemma: Either (i) what is a priori is a contingent matter or (ii) it is possible that something is a priori but false. In this talk, I will survey some options for addressing this problem from the perspective of a two-dimensional propositional modal logic with operators both for the modalities of “necessity” and “apriority”. I will demonstrate the undesirable consequences of Chalmers and Rabern’s (2014) semantics for apriority, which appeals to a liveness constraint, and then argue that the alternative proposal of Johannesson and Packalén’s (2016) suffers from a Gettier-style objection. I conclude by exploring a solution which adds a truth predicate to the two-dimensional system.

Susanne Bobzien (Oxford), Intuitionism and the Modal Logic of Vagueness (joint work with Ian Rumfitt)
Intuitionistic logic provides an neat solution to the Sorites Paradox which avoids the implausible sharp cut-offs in classically based theories. Its acceptance as the correct logic for vagueness has been hampered by two factors. First, the lack of an agreed semantics for languages containing vague terms has led even philosophers sympathetic to intuitionism to complain that no explanation has been given of why intuitionistic logic is the correct logic for such languages. Second, switching from classical to intuitionistic logic does not appear to help with the so-called paradoxes of higher-order vagueness. We offer a proposal that makes strides on both issues. We argue that the intuitionist’s characteristic rejection of any third alethic status alongside true and false is best elaborated by taking the normal modal system S4M to be the sentential logic of the operator ‘it is clearly the case that’. S4M is one of the modal counterparts of the intuitionistic sentential calculus (IPC) and we use this fact to explain why IPC is a correct sentential logic to use when reasoning with vague statements. Our explanation assumes nothing about the form of a semantic theory for a language with vague terms. To start with, the sentential logic that underpins S4M is assumed to be classical, but we also show that our key results go through in an intuitionistic version of S4M. In both its classical and intuitionistic versions, S4M opens the way to an account of higher-order vagueness which avoids the paradoxes that have been thought to infect the notion.

Peter Fritz (Oslo), Possible Worlds in Higher-Order Logic
Let intensionalism be the view that necessarily equivalent propositions are identical. Assuming intensionalism, there is a promising account of possible worlds according to which they are special propositions, namely those which are possible although maximally strong. For such propositions to behave as worlds are widely expected to behave, it is necessary that each possible proposition can be strengthened to a maximally strong one; call this claim "atomicity". Using higher-order logic as a framework in which to regiment our talk of propositions, properties and relations, this talk will explain why atomicity does not follow straightforwardly from intensionalism, but also show that it follows with plausible additional assumptions once the framework is expanded to include higher-order analogues of plural quantifiers. These considerations will presuppose necessitism, the claim that it is necessary what there is. The talk will conclude by sketching some of the ways in which the situation becomes much more complicated when necessitism is rejected.

Wesley Holliday (Berkeley), From Worlds to Possibilities…and Back?
Possibility semantics for modal logic, originating in Lloyd Humberstone’s 1981 paper “From Worlds to Possibilities”, is a generalization of possible world semantics based on partially ordered sets of region-like “possibilities” instead of only point-like “worlds". A key aspect of the generalization is in not imposing the atomicity requirement that every possibility is refined by a maximally specific possibility or “world". This is the source of the mathematical and logic interest of possibility semantics for basic modal languages (see https://escholarship.org/uc/item/0tm6b30q). Imposing the atomicity requirement would render possibility semantics for these languages no more general than possible world semantics, though there would still be advantages for extended modal languages. In this talk, I will briefly outline the mathematical and logical interest of possibility semantics, but my main goal is to discuss whether possibility semantics—with the rejection of the atomicity requirement—is of philosophical interest. Some philosophers, including Bob Hale and Ian Rumfitt, have explicitly rejected the atomicity requirement for possibilities. Other philosophers, including Kit Fine, have argued that every proposition is entailed by a world proposition, which in the context of possibility semantics implies the atomicity requirement. I will aim to refute these arguments, as formalized in modal logic with propositional quantifiers and an actuality operator. In the course of my response, I will discuss a distinctive kind of propositional contingentism that can be incorporated in possibility semantics.

Øystein Linnebo (Oslo), Predicativism and potential infinity (joint work with Stewart Shapiro)
We develop some predicativist approaches within the modal framework for potentiality that was developed in Linnebo (2010) and Linnebo and Shapiro (2018). The result is illuminating, as it puts predicativism into a more general framework and helps to sharpen some of the key theses.

Stephan Leuenberger (Glasgow), Fragmentation and introspection in epistemic logic (joint work with Martin Smith)
All standard epistemic and doxastic logics legitimate something akin to the principle of closure. And yet the principle of closure, particularly in its multiple premise guise, has a somewhat ambivalent status within epistemology. In this paper we describe a family of weak logics in which closure fails, and describe two alternative semantic frameworks in which these logics can be modelled. One of these – which we term plurality semantics – is relatively unfamilar and unexplored. What makes this framework significant is that it can be interpreted in a very natural way in light of one motivation for rejecting closure: that epistemic agents may be fragmented. Fragmentation is one way of falling short of an epistemic or doxastic ideal. Another one, which has taken central stage in traditional epistemic and doxastic logic, is lack of introspection. The paper then investigates the relationship between these two dimensions of non-ideality.

Organizer
Stephan Leuenberger and Peter Fritz

Afternoon Workshop on Analyticity and Easy Being

Time and place: June 6, 2018 12:00 PM–3:30 PM, Gm 652, University of Oslo

Anyone interested is invited to participate in an afternoon workshop at the University of Oslo which explores the natures of, and possible connections between conceptual truths and ontology.

Date: 6th of June.
Time: 12.00 – 15.30
Place: University of Oslo, Philosophy Department
Format: 40min presentation, 35min discussion.

Program:

12.15-12.30: Introductory remarks by Øystein Linnebo, University of Oslo

12.30-13.45: Tobias Alexius, Uppsala University, ‘Formal Analyticity and Easy ontology’

Abstract: Amie Thomasson has argued that we can settle ontological disputes with the help of easy arguments that involve conceptual truths (Thomasson 2015). This forces her to mount a defense of the notion of conceptual truth. In this talk I argue that whilst Thomasson fails to defend a general notion of analyticity from the attacks mounted by Timothy Williamson (2007), Zeynep Soysal’s (2017) defense of formal analyticity is successful. Furthermore, Soysal’s defense of analyticity gives us resources to build and defend, within a Thomasson-esque framework, a liberal ontology, but it fails ground a defense of traditionally contentious entities like tables, cars, numbers and propositions.

13.45-14.15: Pause (Coffee)

14.15-15.30: Robert Schwartzkopff, University of Hamburg, "Easy Arguments, Nominalizations, and Higher-Orderism"

References:

Soysal, Z., (2017) ‘Formal Analyticity’, Philosophical Studies, DOI 10.1007/s11098-017-0982-6

Thomasson, A., (2015) Ontology Made Easy, Oxford university Press.

Williamson, T., The philosophy of philosophy, Blackwell Publishing.

One day workshop: ConceptLab and Conceptual Engineering: Taking Stock

Time and place: June 1, 2018 9:00 AM–5:00 PM, GM 652, University of Oslo

Program

Session 1: 9:00 - 10:00

Herman Cappelen

I present an overview of the work I have done on the theoretical framework for conceptual engineering during the first two years of the NFR funded project on Conceptual Engineering. I outline results, challenges, and plans for the next three years.

Øystein Linnebo: "Engineering of formal concepts"

I provide an overview of how I want to “engineer” some formal concepts, in particular, collection, infinity, generality, object, and truth. I review what has been done and what remains.

Session 2: 10:10 - 10:50

Camilla Serck-Hanssen: "Conceptual Engineering and Societal Impact. Experience from the Military Sector”

General discussion of connections between our three research themes

Session 3: 11:00 - 12:15

Patrick Greenough: "Applied Conceptual Engineering"

Does Conceptual Engineering (and Conception Engineering) take place outside of philosophy? In what ways? And should it? And in what ways? In this highly exploratory talk, I consider how to apply Conceptual/Conception Engineering beyond strictly philosophical debates. My particular focus will be something I call: Conceptual Consultancy. This involves giving some kind of conceptual assessment—a conceptual health-check—of a group, society, corporation, government body, charity, NGO, and so on. It turns out that many companies often ask themselves “why are we doing what we do?”, yet they lack any of the conceptual resources to answer such questions. Hence, Conceptual Consultancy. (I hope to arrange a workshop within ConceptLab on this topic—so this is really just a pilot for that.)

Rachel Sterken: "New Frontiers of Speech"

David Plunkett: “The normative foundations of conceptual ethics”

Session 4: 12:50 - 13:40

Dragana Bozin: "Conceptual Engineering and Conceptual Change in Exact Sciences: friends or foes?"

Andrew Peet: "Meaning and Meaning Change"

One of the biggest challenges I have been faced with when theorizing about conceptual engineering is the puzzles which seem to arise from the very possibility of intentional meaning change. Thinking about conceptual engineering has forced me to re-assess many of my prior beliefs about language and meaning. In this talk, I will briefly present one puzzle (drawn from parts of Herman’s book ‘Fixing Language’), and I will present an account of the nature of linguistic meaning which I believe helps us resolve the puzzle. The puzzle is as follows: On the one hand, semantic externalism is true. The meanings of our words depend on our environment, and patterns of use within our linguistic community. This suggests that we, as individuals, have very little control over the meanings of our terms. On the other hand, it seems like there are obvious cases in which we, as individuals, are masters of our meanings. For example, if I stipulate in a paper that ‘intuition’ should be taken to mean ‘immediate phenomenal seeming following consideration of a thought experiment’, then my future uses of ‘intuition’ in that paper will have that meaning. I believe we can resolve this tension by thinking about the function of meaning ascriptions. Theorists usually assume that public meanings play an essential role in communication. I am not convinced that this is the case. Rather, I suspect that talk of utterance meaning is used to track and talk about the responsibilities speakers undertake when they make utterances. This fits well with an ‘interpreter’ based view of utterance meaning, similar to that espoused by Wettstein (1984) (followed by Romdenh-Romluc (2002), and Gauker (2008)). I will suggest that such views resolve the tension between semantic externalism and the possibility of intentional meaning change.

Session 5: 13:50 - 14:40

Sigurd Jorem: "What the very idea of giving necessary and sufficient conditions teaches us about philosophy"

In this talk, I outline one of the arguments I shall be developing in my impending PhD project, to justify the claim that philosophical theories can permissibly engage in conceptual revision. Traditional conceptual analyses have been subject to the requirements that the application conditions they assign should match with our deployment patterns or intuition, that the conditions are informative or somehow non-circular and that the conditions are necessary and sufficient for applying the target concept. Psychological evidence indicates that our deplyoment patterns give little reason to suppose that we possess concepts as if they were governed by necessary and sufficient conditions. For some, this is a reason to abandon the project of giving necessary and sufficient conditions. Here, I argue that a more plausible solution is to abandon the first requirement, that our (would-be) analyses must conform to the concepts we already have, as given by intuition and deployment patterns.

Joey Pollock: "Conceptual engineering and content individuation"

My plan is to talk about why we might prefer internalism as a framework for understanding conceptual engineering.

Session 6: 15:00 - 15:50

Peter Fritz: "Higher-Order Logic as Conceptual Engineering"

A number of philosophers have recently endorsed primitivism about higher-order logic, the claim that higher-order quantifiers have an intended interpretation which is not reducible to any formal proof system or model-theoretic semantics. I argue that such a primitivism can be motivated from the viewpoint of conceptual engineering, and discuss some methodological consequences of this perspective.

Sam Roberts: "Conceptions of properties"

Session 7: 16:00 - 16:50

Andreas Brekke Carlsson: "Responsibility, verbal disputes and revision"

Lars Christie: "Disentangling conceptual and normative disputes in ethics of punishment and self-defense"

Mini-workshop on Grounding

Time and place: May 31, 2018 10:00 AM–4:00 PM, GM 452

Schedule:

10:00-11:00 Talk by Luca Zanetti (Pavia): "Grounds by T-biconditionals"
11:00-12:00 Discussion of pre-read material on puzzles of ground
12:00-13:00 break
13:00-14:30 Talk by Jon Litland (Texas): "Ways of Ground"
14:30-16:00 Talk by Peter Fritz (Oslo): "Ground and Grain"

Abstract of "Grounds by T-biconditionals" (Luca Zanetti):

Intuition says that if the proposition that p is true, then that proposition is true because p and not vice versa. Benjamin Schnieder claims that explanations with this form are conceptual rather than genuinely metaphysical explanations; however, David Liggins has recently set two challenges for this 'conceptual' account. In this paper I proceed as follows. As for the first challenge, I will say that the problem is analogous to an objection raised against neo-Fregeanism in the philosophy of mathematics, and can be addressed in the same way. I also offer an independent reply to the objection. As for the second challenge, I firstly show that it is a problem also for neo-Fregeanism; I then suggest a reply. I finally consider a new challenge for my second reply and offer an 'hybrid' account in terms of conceptual grounding.

Material on Puzzles of Ground:

Fine, Kit. Some Puzzles of Ground, Notre Dame Journal of Formal Logic 51, pp. 97-118, 2010.
Krämer, Stephan. A Simpler Puzzle of Ground, Thought 2, pp. 85-89, 2013.
Correia, Fabrice. Logical Grounds, Review of Symbolic Logic 7, pp. 31-59, 2014.

Abstract of "Ways of Ground" (Jon Litland):

It is tempting to use immediate ground to individuate propositions in the following way: two propositions are identical iff they have the same immediate grounds. But this, arguably, makes propositions too coarse-grained. For instance, if the immediate grounds for the existence of a set are just the existence of its members, and the grounds for the existence of a fusion is just the existence of its proper parts one is forced to identify the proposition that the sum of Plato and Socrates exists with the proposition that the set of Socrates and Plato exists. In the first half of the talk I propose that we should take seriously that propositions are grounded in different ways and that propositions are identical iff they have the same immediate grounds and are grounded in the same way. I propose to identify ways of ground with (certain) functions from (pluralities of) propositions to propositions. The resulting conception of proposition is very fine-grained: and so versions of the Russell-Myhill paradox threaten. In the second half of the talk, I attempt to extend some ideas due to Fine and Linnebo to show how we can avoid paradox while keeping a fairly fine-grained view of propositions.

Abstract of "Ground and Grain" (Peter Fritz):

There is a tension in recent theorizing about grounding: On the one hand, grounding is usually formulated using a sentential connective, which means that quantificational talk about grounding is most naturally understood as involving quantification into sentence position. On the other hand, grounding theorists usually hold that grounding draws very fine distinctions, requiring its relata to be very finely individuated. These two commitments turn out to be in tension, since we can prove using highly plausible inferences of a purely logical character -- uncritically presupposed in much of the writing on grounding -- that what quantifiers binding variables in sentence position range over cannot be as fine-grained as required by grounding theorists. This paper presents this tension, and develops a possible response. According to the proposed response, there is not a single sentential grounding connective, but an array of grounding connectives which relate complexes of a certain kind in a hierarchy of types, the theory of which is developed here as well. It is shown that this proposal also provides new and attractive solutions to a range of other puzzles of ground.

Organizer

Peter Fritz

Workshop: Kant, Paradoxes and Conceptual Engineering

Time and place: May 29, 2018 9:00 AM–5:00 PM, GM 652, University of Oslo

Program

09:00-10:30 Guido Kreis: "The idea of transcendental analysis"
10:45-12:15 Toni Kannisto:"Transcendental Arguments and the Possibility of Synthetic A Priori Metaphysics"
12:15-13:15 Lunch
13:15-14:45 Frode Kjosavik:"On a Kantian framework for conceptualization within the formal sciences"
15:00-16:30 Camilla Serck-Hanssen:"Kantian Critique as Conceptual Engineering"
16:30-17:00 General Discussion

Gudio Kreis: The idea of transcendental analysis

The aim of this paper is to reconstruct Kant’s philosophical method as transcendental analysis. I shall start with briefly discussing Hermann Cohen’s Neo-Kantian account of transcendental method, that first introduced the concept of transcendental analysis into Kant interpretation. I shall then examine, by way of comparison with several main varieties of analysis, in what sense transcendental analysis might qualify as philosophical analysis at all, and conclude that it constitutes a variety sui generis. Most importantly, by way of discussing Kant’s distinction between analytic and synthetic method in philosophy, I argue that transcendental analysis must not be regarded as a method of demonstration in the sense of the mathematical method of regressive analysis. Rather, it should be seen as an explication and systematisation of the necessary conditions of our conceptual scheme. I try to clarify this point by drawing out what I take to be striking parallels between both Kant’s transcendental method and Strawson’s conception of descriptive metaphysics.

Guido Kreis is Associate Professor in Philosophy at Aarhus University (Denmark). He received his Dr phil from Heidelberg University in 1999 and his Habilitation from Bonn University in 2014. His main areas of research are Kant and German Idealism (especially Hegel) and their reception in 20th century philosophy, Neo-Kantianism (Cassirer), metaphysics, philosophy of culture, and aesthetics. Main publications: Cassirer und die Formen des Geistes (“Cassirer and the Forms of Spirit”, Berlin: Suhrkamp, 2010); Negative Dialektik des Unendlichen: Kant, Hegel, Cantor (“Negative Dialectics of the Infinite: Kant, Hegel, Cantor”, Berlin: Suhrkamp, 2015); Gottesbeweise von Anselm bis Gödel (“Arguments for the existence of God: from Anselm to Goedel”, Berlin: Suhrkamp, 2011, co-ed. with Joachim Bromand).

Frode Kjosavik: On a Kantian framework for conceptualization within the formal sciences

Kant had a conservative view of both logic and mathematics. Logic was considered to be fixed by the forms of thought. By contrast, mathematics was acknowledged as an arena for introducing new concepts through “arbitrary synthesis” in the medium of “pure intuition.” However, mathematics is thereby also constrained by general constructibility conditions – “forms of intuition.” On the other hand, Kant’s critical metaphysics not only contains resources for clarification of concepts within the formal sciences but also leaves room for revisions and extensions beyond this. The First and Second Antinomies in the Transcendental Dialectic in CPR lend support to this claim. After all, the antinomies suggest that there can be quasi-constructions by reason that go far beyond the constructions that belong to the understanding. One has to relate to these quasi-constructions in the right way, though. I shall discuss the significance of this in assessing the potential for conceptual novelty according to a broadly Kantian conception of concept formation.

Kjosavik is Professor of Philosophy at the School of Economics and Business, at the Norwegian University of Life Sciences (NMBU). He was group leader, together with Professor Camilla Serck-Hanssen, for the project “Disclosing the Fabric of Reality – The Possibility of Metaphysics in the Age of Science” at the Centre for Advanced Study (CAS) at the Norwegian Academy of Science and Letters, 2015-16. His research interests include general metaphysics and epistemology, history of philosophy, philosophy of perception, and philosophy of science. He has published articles on Kant, Husserl, the philosophy of mathematics, and the philosophy of biology. He is co-editor of Husserl’s Phenomenology of Intersubjectivity. Historical Interpretations and Contemporary Applications. (Forthcoming, Routledge.)

Toni Kannisto: Transcendental Arguments and the Possibility of Synthetic A Priori Metaphysics

In this talk I will advocate transcendental argumentation as a valid method of metaphysics, understood as a synthetic a priori science of the fundamental features of all possibly existing objects. I will utilise the logic of counterfactuals to develop a novel formalisation of transcendental argumentation that has several virtues. First, it captures formally the idea that transcendental argumentation infers to necessary presuppositions rather than to consequences of premises. Second, it establishes transcendental argumentation as formally distinct from other necessity-wielding argumentation (e.g. analytical and mathematical). Third, it demonstrates as necessary rather than merely presupposes the traditional connection transcendental argumentation has to mental capacities (e.g. experience, perception, and language). Fourth, it shows that transcendental argumentation affords metaphysical results in case transcendental idealism is presupposed. Hence it vindicates transcendental idealism as a powerful meta-metaphysical theory that can establish transcendental argumentation as the proper and unique method for justifying synthetic a priori propositions of metaphysics.

Camilla Serck-Hanssen: Kantian Critique as Conceptual Engineering

Conceptual engineering is a new field of philosophy that seeks to critique and improve concepts, i.e. to ameliorate and sometimes replace defective concepts. As such it is a normative endeavor to “fix” language and to improve our representational devises or concepts. In this talk I will explain why I take Kant to be a conceptual engineer. Specifically, I will suggest that his critique of the concepts of special metaphysics should be understood not as therapy depending on the truth of transcendental idealism, but rather as resting on his normative engineering of the formal concept of negation. I also suggest how Kant would answer some of the challenges that conceptual engineering faces, such as the question of what the object of engineering is, what concepts are, and what method it should use. I will conclude by exemplifying how my reading works with the second paralogism of simplicity, the so-called Achilles argument of the A-edition Paralogisms.

Organizer

Camilla Serck-Hanssen

The 1st Social Epistemology Network Event (SENE)

With keynote talks, early career sessions and contributed talks.More information to come.

Time and place: May 22, 2018 9:00 AM–May 24, 2018 6:00 PM, Centre for the Study of Mind in Nature, University of Oslo

Keynote Talks

Cristina Bicchieri (University of Pennsylvania)
Sandy Goldberg (Northwestern University)
Alvin Goldman (Rutgers University)
Katherine Hawley (University of St Andrews)
Paulina Sliwa (Cambridge University)
Early Career Sessions
Adina Covaci (University of Leeds): Against Moral Deference Again
Haixin Dang (Univerrsity of Pittsburgh): Epistemic Responsibility in Science
Lewis Ross (University of St Andrews): What is the Locus of Scientific Progress?
Eric Sampson (University of North Carolina at Chapel Hill): Can We Rationally Believe Conciliationism?

Contributed Talks

Mark Alfano (Delft University of Technology): Virtues for Agents in Directed Social Networks
Katherine Dormandy (Innsbruck University): Types of Belief on Authority
Paul Faulkner (University of Sheffield): On Conversion
Carrie Figdor (University of Iowa): Trust Me - News, Credibility Deficits and Balance
Axel Gelfert (Technical University of Berlin): What Is Fake News?
Mikkel Gerken (University of Southern Denmark): Epistemic Diversity and Epistemic Injustice
Jesper Kallestrup (University of Edinburgh): The Epistemology of Testimonial Trust
Mihaela Popa-Wyatt (University of Birmingham): How Speech Alters Norms
Robin McKenna (University of Vienna): Is Knowledge Socially Constructed?
Joey Pollock (University of Edinburgh): Linguistic Understanding and Testimonial Warrant
Lani Watson (University of Edinburgh): What Are Epistemic Rights?
Stephen Wright (University of Oxford): Testimony, Knowledge and Reliability

Generously funded by the Centre for the Study of Mind in Nature (CSMN) at the University of Oslo.

For more information about the speakers and registration, see the Social Epistemology Network website.

Organizer

Andrew Peet (Oslo) and Mona Simion (Cardiff)

Talk by Jean-Yves Beziau. "MANY 1 -A Transversal Imaginative Journey across the Realm of Mathematics"

Time and place: May 18, 2018 3:00 PM–4:00 PM, University of Oslo, GM 652

Engineering logical concepts

Time and place: Mar. 8, 2018–Mar. 9, 2018, University of Oslo

Topic

Conceptual engineering is the study of conceptual deficiencies and ways in which these can be addressed. The workshop aims to explore whether, and if so how, this approach can and should be applied to the philosophy of logic.

Questions might include the following:
In what ways can logical concepts be deficient? (inconsistency, conflation of concepts, disharmony, not joint-carving, unintuitive, etc)
In what ways can logical concepts be improved?
Are logical concepts like other scientific concepts with regard to the previous questions? (yes, because logical expressions are theoretical terms; no, because logic is exceptional)
What is the philosophical status of such improvements (replacement or revision)?
Are logical concepts different from most other scientific concepts by being formal in some sense?
The role of stipulation and definition in fixing logical concepts
Do logical concepts play some special role in our cognitive architecture?

Program

8 March

9:15 - 10:30: Ole Hjortland "Engineering logical concepts"
10:45 - 12: Øystein Linnebo "The paradox of the largest number"
12:45 - 2pm: Eric Snyder & Steward Shapiro "Plurality and Paradox"
2:15 - 3:30pm: Peter Fritz "In Defense of Higher-Order Logic"
3:45 - 5pm: Marcus Rossberg "Engineering Logical Concepts?”

9 March

9:30 - 10:45: Craige Roberts & Steward Shapiro "Open-texture, analyticity, model theory, and natural language semantics"
11 - 12:15: Gil Sagi "Logic and Natural Language"
Lunch
1:15 - 2:30pm: Hannes Leitgeb "Models with Non-Representing Concepts: Logicality, Analyticity, Metaphysics"
2:45 - 4pm: Kevin Scharp

Peter Fritz

Title: In Defense of Higher-Order Logic

Abstract:

According to a common argument, higher-order logic is incoherent,
since using higher-order logic commits one to claims about
higher-order logic which cannot be expressed in higher-order logic. I
defend higher-order logic against this argument, by clarifying and
distinguishing different versions of it, and showing how its premises
may plausibly be rejected.

Ole Hjortland

TITLE: Engineering logical concepts
ABSTRACT: Anti-exceptionalism about logic is the Quinean view that
logical theories have no special epistemological status, in
particular, they are not self-evident or justified a priori. Instead,
logical theories are continuous with scientific theories, and
knowledge of logic is as hard-earned as knowledge of physics,
economics, and chemistry. In this paper, I explore how an
anti-exceptionalist should think about logical concepts, and I argue
for a view according to which logical concepts are the result of
conceptual engineering. The view in turn helps block the so-called
meaning-variance argument, and it supports an anti-exceptionalist
story about theory choice in logic.

Hannes Leitgeb

TITLE: "Models with Non-Representing Concepts: Logicality, Analyticity, Metaphysics"

Øystein Linnebo

TITLE: "The paradox of the largest number"

Is there a largest number? Attempts to answer the question easily lead
to paradox: we are attracted to both a positive and a negative answer.
I show how the paradox can be avoided by adopting either an
Aristotelian conception of potential infinity or--far more
plausibly--a “successor concept” that is compatible with Cantor’s
theory of the transfinite.

Craige Roberts and Stewart Shapiro

TITLE: "Open-texture, analyticity, model theory, and natural language semantics"

The purpose of this paper is to articulate and evaluate Waismann's
notion of open-texture, from the "Verifiability" paper, and some of
the themes in his "Analyticity" series. One underlying theme is how
far open-texture reaches. Do we follow Waismann and restrict it to
empirical predicates, or is the phenomenon more general, applying even
in science and mathematics? Our goal is to explore the extent to
which the Waismannian insights bear on the enterprise of natural
language semantics and of the model-theoretic notion of logical
consequence. Does the fact that contemporary model theory, and many of
the models for lexical semantics, allow no room for open-texture tell
against those enterprises, as they are currently practiced?

Marcus Rossberg

TITLE: "Engineering Logical Concepts?”

Abstract:
I will start from the question why the engineering of logical concepts
should deserve any special attention. Is it any different from
engineering other concepts? The investigation detours via a dispute
between Quine and Carnap and comes to considering the relation between
conceptual engineering and ideal language philosophy. I argue that
the conceptual engineering project would benefit from moving closer to
the older, and more radical, conception of explication in an ideal
language.

Gil Sagi

TITLE: "Logic and Natural Language"

Searle has famously stated that ``Neither Aristotelian nor Russellian
rules give the exact logic of any expression of ordinary language; for
ordinary language has no exact logic.’’ On the other hand, we have
Montague, who claimed: ``There is in my opinion no important
theoretical difference between natural languages and the artificial
languages of logicians’’, and went on to characterize the logic of
natural language. This talk will address the question of whether there
is logic in natural language. However, to understand this question we
need to say what we mean by ``logic’’, ``natural language’’, and logic
being ``in’’ natural language. There are various things we may mean by
these terms that will make us reach different conclusions. I will
offer two routes of explicating the terms involved, which seem to me
most interesting, and by which we obtain different results for the
question at hand.

Stewart Shapiro and Eric Snyder

TITLE: "Plurality and Paradox"
Abstract: There are two general approaches to analyzing plurality in
natural language. The first, which is standard within linguistic
semantics, is singularism. It posits a single reference relation and
analyzes singular and plural nouns via it: singular nouns denote
singular individuals (or "atoms"), while plural nouns denote plural
individuals (or "pluralities"), usually modeled as sums of singular
individuals. The second approach, prominent within philosophy, is
pluralism. It posits two reference relations -- singular reference and
plural reference -- and analyzes plural nouns via the latter. The
important difference between these approaches is that whereas
singularism posits set-like entities as the referents of plural terms,
pluralism does not. Moreover, the primary argument against singularism
is that because such set-like entities iterate, singularism inevitably
leads to Russell's Paradox, and so is ultimately incoherent. We defend
singularism against this charge by establishing three claims. First,
there are natural language examples involving plurals which cannot be
adequately captured by the pluralist semantics. Rather, adequately
capturing their meanings requires positing set-like entities as the
referents of certain plural terms. Secondly, these set-like entities
-- pluralities and groups -- iterate, and it is indeed possible to
formulate a version of Russell's Paradox for each. These take the same
form as Linnebo (2010)'s derivation of Russell's Paradox for sets
within pluralism. Third, and most significantly, Linnebo's strategy
for harnessing Rusell's Paradox for sets extends naturally and
elegantly to the versions involving pluralities and groups. In all
three cases, by modalizing the characterizing principles, we get an
intuitive and general resolution to Russell's Paradox for set-like
entities: set-formation, plurality-formation, and group-formation are
best understood as potential, rather than completed or actual,
processes.

Organizer

Øystein Linnebo (University of Oslo/ConceptLab) and Ole Hjortland (University of Bergen/Anti-exceptionalism about logic)

2017

Conference on Conceptual Engineering (at University of Toronto)

Time and place: Dec. 2, 2017 8:30 AM – 5:40 PM, University of Toronto

ConceptLab in collaboration with Gurpreet Rattan at the University of Toronto is organising a one-day conference on Conceptual Engineering.

Assertion-Foundational Issues

Time and place: Sep. 6, 2017 – Sep. 7, 2017, University of Oslo, GM 652

Program

Wednesday, September 6

Casey Johnson: 'Illocutionary Monism and Illocutionary Pluralism'
Herman Cappelen: 'The 'No Assertion' View'
Manuel Garcia-Carpintero: 'Are Constitutively Normative Practices Necessarily Non-Conventional?'
Peter Graham: 'Assertion and Social Norms'

Thursday, September 7

Janet Levin: 'Norms of Assertion in the Age of Twitter'
Peter van Elswyk: 'Demarcating Assertion'
Mona SImion & Chris Kelp: 'Assertion: The Constitutive Norms View'
Patrick Greenough: 'Relativism and Assertion'

Workshop: Critical views of logic

Time and place: Aug. 29, 2017 – Aug. 30, 2017, University of Oslo

The workshop explores what we call “critical views of logic”. Following Frege, logic is often regarded as epistemologically and methodologically fundamental. All disciplines--including mathematics--are answerable to logic rather than vice versa. Critical views of logic disagree; Kant, Poincaré, and Brouwer are prominent examples. The logical principles that govern some subject matter may depend on the metaphysics of this subject matter or the semantics of our discourse about it. The notions of potential infinity and indefinite extensibility are important in this regard. Many theorists claim that a potentially infinite domain calls for intuitionistic logic, not classical.

Program

August 29

Øystein Linnebo, Welcome

Morning Session, Chair: Øystein Linnebo

Carl Posy, Hebrew University of Jerusalem: “Infinity and the Critical Turn: Revisiting Kant and Brouwer”
Frode Kjosavik, Norwegian University of Life Sciences: “Kant on the possibilities of mathematics and the scope and limits of logic”

Afternoon Session, Chair: Frode Kjosavik

Dora Achourioti, University of Amsterdam: ”Kant, Logic and Truth”
Per Martin-Löf, Stockholm University: “Assertion and request”
Mirja Hartimo, University of Jyväskylä: “Logic and Husserl’s Philosophy of Mathematics”

August 30

Morning Session, Chair: Dagfinn Føllesdal

Mark van Atten, CNRS: “Dummett vs Brouwer”
Øystein Linnebo, University of Oslo: “Dummett on indefinite extensibility”

Afternoon Session, Chair: Mirja Hartimo

Göran Sundholm, Leiden University: “Completeness Theorem? So what!”
Ole Hjortland, University of Bergen: “Theories of truth and the maxim of minimal mutilation”
John Wigglesworth, University of Vienna: “Logical Anti-Exceptionalism and Theoretical Equivalence”

Funded by NMBU and ConceptLab

ELAC Annual Conference: "Justifying Preventive Harm: Retributive and Distributive Approaches”.

The event is a collaboration between ConceptLab and The Oxford Institute for Ethics, Law and Armed Conflict (ELAC)

Time and place: Aug. 17, 2017 – Aug. 18, 2017, Oslo Militære Samfund

The 8th Annual Conference of the Oxford Institute for Ethics, Law and Armed Conflict is hosted this year University of Oslo’s ConceptLab at the Oslo Military Society.

ELAC is an interdisciplinary research programme that aims to strengthen law, norms and institutions to restrain, regulate and prevent armed conflict.

Speakers

John Gardner (Oxford), Richard Arneson (UCSD), Susanne Burri (LSE), Lars Christie (Oxford/University of Oslo), Patrick Tomlin (Reading), Doug Husak (Rutgers), Jovana Davidovic (University of Iowa)

Respondents

Helen Frowe (Stockholm), Andreas Carlsson (University of Oslo/Norwegian Defence Ethics Council), Michael Robillard (Oxford), David Rodin (Oxford).

Benjamin Matheson, Kartik Upadhyaya, Korbinian Ruger

Programme

Day 1 - Thursday August 17

Session 1. Distributive Wars: Richard Arneson (USCD)

Many hold that war under modern conditions can only be justified when its goal is defense of national sovereignty (or, more broadly, group autonomy) or perhaps the reduction of extreme and large-scale violations of basic human rights. On this view a paradigm of unjust war would be one for distributive aims: Country A, whose members are not in dire need, makes war on country B, whose members are on the whole better off, in order to rectify the distribution if resources of welfare across A and B. Another paradigm unjust cause: Country A makes war on country B in order to rectify the distribution of resources or welfare among the members of country B. So many hold. –On the contrary, we should accept that wars for distributive aims can be morally permissible and even mandatory. One key is to identify a plausible account of distributive justice. Another key is to note that wars need not necessarily involve enormous broad-ranging violence whose harmful effects fall indiscriminately; a war can involve small-scale violence, violence aimed with precision at specific targets, and even no violence at all, merely credible strong threat. Allowing that distributive aims can justify war is compatible with acknowledging that the conditions for justification are stringent and perhaps rarely met. We should also note that policies and practices aimed at advancing distributive justice within a country in ordinary peacetime can impose uncompensated harms on innocent bystanders without hereby automatically qualifying as unjustified.

Respondent: Helen Frowe

Session 2. Distributing Harms among Liable Aggressors: Patrick Tomlin (Reading)

The individualist nature of much contemporary just war theory means that we often discuss cases with single attackers. But even if war is best understood in this individualist way, in war combatants often have to make decisions about how to distribute harms among a plurality of individual aggressors. In this paper, I distinguish two different kinds of cases of in which we face a plurality of aggressors – simultaneous attacks and sequential attacks (the reality of war is that we will face an amalgam of these archetypes – sequential simultaneous attacks). I then focus on simultaneous attacks, and in particular cases in which more than one distribution of harm among (potentially) liable aggressors will prevent an attack. I show how such cases pose questions concerning the nature and role of the necessity principle, and its relationship to narrow proportionality. I argue that a hitherto unrecognised measure – ‘narrow proportionality shortfall’ – and its distribution is relevant in choosing how to distribute harms across (potentially) liable aggressors. I then extend this analysis to show how this may help us with some puzzles concerning sequential attacks.

Respondent: Benjamin Matheson

Session 3. Liability to Defensive Harm, Forfeiture Theories of Rights and Relational Theories of Rights: Jovana Davidovic

According to forfeiture theories of rights one can become liable to defensive harm when they act in ways that forfeit their right not to be harmed. For example, when they unjustifiably threaten harm to innocent victims. Forfeiture theories are traditionally normative theories; they are attempts to justify imposing harm on culpable or morally responsible aggressors. In this paper, I argue that forfeiture is best understood as a conceptual rather than a normative or justificatory aspect of the right not to be harmed. I argue that understanding forfeiture in this way can nonetheless put limits on the sorts of justifications one can offer for grounding the right not to be harmed and consequently for liability to defensive harm. Specifically, I argue that understanding forfeiture as a conceptual feature of the right not to be harmed gives us reasons to embrace relational, inter-agential grounding for that and similar rights; a grounding that in addition to protection of an interest requires that an agent respect similar protections for others. Furthermore, I argue that understanding forfeiture as a conceptual feature of rights can also help fill noted gaps in forfeiture accounts: the so-called mechanism gap and the central normative transition gap.

Respondent: David Rodin

Session 4. Foreseeability, Moral Responsibility, and Liability to Defensive Harm: Susanne Burri (LSE)

Consider the following two cases: The Conscientious Driver.1 A person who always keeps her car well maintained and always drives carefully decides to drive to the cinema. On the way, a freak event that she could not have anticipated occurs that causes her car to veer out of control in the direction of a pedestrian. Day's End.2 A homeowner always come home at 9 pm and the rst thing he does is ip the light switch in his hallway. He is about to do so this evening. The homeowner's ipping the switch causes a circuit to close. By virtue of an extraordinary series of coincidences, on this particular evening the circuit's closing will cause a a small lightning ash in a neighbouring house. The lightning ash threatens the life of an unsuspecting neighbour. Both the conscientious driver and the homeowner are non-culpably threatening the life of an innocent other. But according to Je McMahan (2009), there is nevertheless an important moral di erence between the two, in that only the conscientious driver was able to foresee|in a sense to be speci ed|that her action might cause serious harm. For McMahan, this means that the conscientious driver, but not the homeowner, is liable to defensive harm: if the pedestrian could save himself by throwing a grenade towards the conscientious driver's car, he would be morally permitted to do so. The homeowner's neighbour, by contrast, lacks a similar moral permission to defend himself. In this paper, I investigate whether McMahan is right to claim that the harm threatened by the conscientious driver is foreseeable in a way that the harm threatened by the homeowner is not. I conclude that a principled distinction between the two agents can be drawn, but that the difference might not be as morally weighty as McMahan thinks it is.

Respondent: Henrik Syse

Day 2 Friday August 18

Session 1. The Punishment/Self-Defence Distinction: John Gardner (Oxford)

I will discuss three questions. First, is there a secure distinction between retributive and distributive justice? Second, is there a sharp(ish) distinction between desert and necessity? Third, should we expect the distinction between punishment and self-defence to hold apart from the existence of social practices that differentiate them? I lean towards negative answers to all three questions. I will therefore raise doubts about recent philosophical writings on self-defence that presuppose affirmative answers to one or more of them.

Respondent: Andreas Brekke Carlsson

Session 2. Punishing attackers in self-defence : Lars Christie (Oxford/UiO)

In my article, I identify a tension between academic writings on punishment and academic writings on self-defence. A number of theorists writing on punishment have advanced the idea that punishment can be justified on similar grounds as self-defence. Yet most theorists of self-defence reject this idea: they are not attracted to the view that the justifications for punitive and defensive harm might rest on similar grounds. At the same time, theorist of self-defence by and large accept the intuitive view that a threatener’s culpability is relevant to the amount of defensive force the victim may use to defend himself. I argue that one cannot insist on the relevance of culpability to defensive harming while at the same time denying the overlap between the justification for punishment and self-defence.

Respondent: Kartik Upadhyaya

Session 3. "The Vast Scope of Preventive Harming", Doug Husak (Rutgers)

Examples of preventive harming are much more commonplace in modern society than many theorists seem to acknowledge. Approximately 70 million persons are potentially affected by the harmful collateral consequences triggered by a mere arrest. This total greatly exceeds the number of cases on which many moral and legal philosophers have tended to focus: those involving incarceration and real or putative instances of self-defense. Without denying the tremendous philosophical interest these latter examples continue to attract, they represent a drop in the bucket when we consider the true extent of preventive harming that is permitted (and sometimes mandated) by law throughout the United States today. But the philosophical significance of my position is normative rather than descriptive. To my mind, it would take a fair amount of creative Gerry-rigging to accommodate many of the collateral consequences I describe within conventional philosophical wisdom about preventive harming.

Respondent: Korbinian Ruger

Non-instance based conceptions of generality

Time and place: Aug. 10, 2017 – Aug. 11, 2017, GM 652, University of Oslo

On a classical conception, a universal generalization is true because each of its instances is true. This workshop will explore alternative, non-instance-based conceptions of universal generality. Why is every object self-identical or ever whale a mammal? Each generalization can be explained, it seems, without invoking any of its instances, perhaps by citing logic or the nature of whales. Are such non-instance-based explanations possible, and if so, how? What consequences might this have for the logic of generality?

Program

Thursday August 10

Gideon Rosen (Princeton), Grounding and Generality,
Bob Hale (Sheffield) What makes true Universal Statements true?
Vera Flocke (NYU) Ontological Expressivism
Øystein Linnebo (Oslo) Generality Explained: A Truthmaker Semantics
Stewart Shapiro (Ohio) Realizability as a kind of truth-making for general statements

Friday August 11

Kit Fine (NYU), Generic Truthmaker Semantics,
Jon Erling Litland (Texas at Austin), Does Everything Exist?
Benjamin Schnieder and Yannick Kappes (Hamburg), Generality, Grounding, and Explanation
Augustin Rayo (MIT) On the Openendedness of Logical Space

Conceptual Truth, Analyticity, and Conceptual Competence

Time and place: June 26, 2017 9:00 AM – June 27, 2017 4:30 PM, Univeristy of Oslo, GM 652

Program

June 26

Åsa Wikforss (Stockholm) "Understanding, Assent and Deviant Speakers"
Mark Richard (Harvard) "Meanings as Species"
Kevin Scharp (St Andrews) "“Constitutive Principles and Meaning Reflection”
Brian Weatherson (Michigan)" Inferentialism and Logical Knowledge"

June 27

Zeynep Soysal (Harvard) ": Analyticity in Set Theory"
Gabriel Oak Rabin (NYUAD) "Toward a Theory of Concept Mastery"
Paul Boghossian (NYU) "Understanding, Intuition and the A Priori”
Timothy Williamson (Oxford): ‘Replies to Objections’

The Practical and Theoretical Implications of Defective Communication

Time and place: June 15, 2017 – June 16, 2017, GM 652, University of Oslo

Linguistic communication can be defective in many ways. We often fail to understand one another, we fail as cooperative communicators, or speak insincerely. The ways in which we communicate can give rise to or facilitate various harms. Such defects have many sources, and raise important theoretical and practical questions. This workshop focuses on such questions.

Program

JUNE 15

Communicating by Miscommunicating, Chi-He Elder (East Anglia)
Transformative Communicative Disruptions, Rachel Sterken (Oslo)
Code Words, Justin Khoo (MIT)
My Friends, You're Gonna Love This One, Eliot Michaelson (KCL)
Lies and Testimonial Worth, Andrew Peet (Oslo)

JUNE 16

Political Dissent in Practice: Insights from Social Theory, Rachel McKinney (Harvard)
We Talk to People, Not Contexts Daniel Harris (CUNY)

Workshop with J. Conant & A. Moore: Descartes, Modality and Conceivability

Time and place: May 23, 2017 9:45 AM – 5:00 PM, George Morgenstiernes hus, room 652

Program

Adrian Moore (Oxford) 'What Descartes Ought to Have Thought About Modality'
James Conant (Chicago) 'Reply to Moore'
Adrian Moore & James Conant open discussion: Descartes, modality and conceivability.

Abstracts

Adrian Moore (Oxford) 'What Descartes Ought to Have Thought About Modality'

My starting point is the first section of James Conant’s wonderful essay ‘The Search for Logically Alien Thought’, in which he discusses Descartes’s views about necessity and possibility. Conant is especially interested in claims that Descartes makes, with respect to propositions that on his own conception are impossible, that God could nevertheless make them true. I argue that these claims are lapses on Descartes’s part: he should not have made them. At the end of my essay I focus on one particularly important case where Descartes not only says what I think he should say, in contradistinction to these lapses, but makes crucial capital out of his entitlement to do so.

James Conant (Chicago) 'Reply to Moore'

Adrian Moore has convincingly shown that the reading of Descartes on modality offered in my earlier essay "The Search for Logically Alien Thought" cannot be right. In my talk I offer an alternative reading of Descartes that aims to recover the grain of truth in my earlier essay.

Interdisciplinary workshop on Generics

Time and place: May 20, 2017 9:00 AM – 5:00 PM, CSLI/Department of Psychology, Stanford University

Provisional Workshop Program

Introductory remarks (Michael Henry Tessler)
Michael Henry Tessler (Stanford, Psychology): Communicating generalizations in computational terms
Rachel Sterken (Oslo, Philosophy)
Andrei Cimpian (NYU, Psychology): Generics and Stereotypes
Student and Postdoc talks
- Arun Chaganty (Stanford, Computer Science): How much is 131 million dollars? Putting numbers in perspective with compositional descriptions
- Nadya Vasilyeva (Berkeley, Psychology): Structural interpretation of category properties
- Ellie Chestnut (Stanford, Psychology) TBA
Susan Gelman (Michigan, Psychology): This time it's personal: What "you" reveals about generic concepts
Bernhard Nickel (Harvard, Philosophy)

Co-organised by Michael Tessler (Stanford, Psychology), Bernhard Nickel (Harvard, Philosophy) and Rachel Sterken (Oslo, Philosophy).

FLASH WORKSHOP at ConceptLab

Time and place: May 19, 2017 2:00 PM – 4:00 PM, Venue: to be announced 2hrs before the workshop. (Somewhere on campus or nearby—so be in the area if you want to participate/attend.)

The Conceptual Principles (core and non-core) for a ConceptLab Flash workshop are:

Theme/Talks: Anything related to ConceptLab issues (broadly construed).
Venue announced 2hrs before Workshop.
Talks will be between 5 minutes and 20 minutes—depending on how many people show up to give a talk.
Be prepared to tailor your talk to different lengths of time.
We work out the schedule, chairs, etc. on the spot depending on who shows up.
There will be a short discussion period for each talk. Typically five minutes.
No Powerpoint allowed.
One-page handout (or less) allowed.
Work in Progress especially welcome – just come along with a hunch or a scruffy idea.
Grad Students especially welcome to present their WIP.
Suggestions (for good venues) especially welcome. (A good place on campus, a quiet coffee bar, bar, pub, church, synagogue, hotel, etc.)

Please get in touch if you are definitely going to give a talk. I will be doing a flash poster so it would be good to put some names on it.

Organizer

Patrick Greenough

Workshop: Meaning Innovation and Meaning Change

Time and place: Mar. 17, 2017 9:00 AM – Mar. 18, 2017 5:00 PM, University of Oslo, GM 652

Program

March 17th

Josh Armstrong (UCLA) "Towards a Dynamic Metasemantics"
Samia Hesni (MIT) "A Good Girl is Tough and Boys Don’t Cry: Normative Generics and Social Kind Terms"
Eric Swanson (Michigan) "Channels for Common Ground"
Robyn Carston (UCL) "Ad Hoc Concepts and the Roots of Polysemy"

March 18th

Peter Pagin (Stockholm) "Meaning change in Switcher Semantics"
Robin Jeshion (USC) "Pride and Prejudiced: On the Creation and Appropriation of Slurs"
Rachel Sterken (Oslo)"Transformative Communicative Disruptions"

Organizer

Josh Armstrong and Rachel Sterken

2016

"Moralske, juridiske og militære utfordringer i krigen mot IS"

Time and place: Sep. 13, 2016 7:00 PM – 9:00 PM, Litteraturhuset i Oslo, Wergelandsvn. 29, Wergelandssalen

Conceptual Engineering Workshop

Time and place: June 16, 2016 – June 17, 2016, Georg Morgenstiernes hus, Blindern campus, University of Oslo

Participants

Mark Richard (Harvard)
Patrick Greenough (St. Andrews)
Ingo Brigandt (Alberta)
Esther Rosario (Alberta)
Amie Thomasson (Miami)
Esa Diaz-Leon (University of Barcelona)
David Plunkett (Dartmouth)
Alejandro Pérez Carballo (Massachusetts, Amherst)
Delia Belleri (Vienna)
Timothy Sundell (Kentucky)
David Braddon-Mitchell (Sydney)
Matti Eklund (Uppsala)
Tristram McPherson (Ohio)
Herman Cappelen (Oslo)
Olav Gjelsvik (Oslo)
Katia Vavova (Mount Holyoke)
Alexis Burgess (UCLA)
Derek Ball (St. Andrews)

Organizer

Herman Cappelen, Olav Gjelsvik and David Plunkett

Cardinality, Worlds and Paradox

Time and place: June 7, 2016 – June 8, 2016, Georg Morgenstiernes hus, room 652

A joint workshop between the Arché Research Centre and the Department of Philosophy at the University of Oslo.

Speakers

Josh Dever (Texas at Austin and Arché)
Peter Fritz (Oslo)
Øystein Linnebo (Oslo)
Toby Meadows (Aberdeen)
Lavinia Picollo (Munich)
Graham Priest (CUNY Graduate Center)
Agustin Rayo (MIT and Oslo)
Stewart Shapiro (OSU)
Gabriel Uzquiano (USC and Arché)

Various relatives of Russell’s paradox have been thought to have important ramifications in logic and metaphysics. It has been thought, for example, that there are strictly more propositions than possible worlds, and that this poses a serious problem for possible worlds semantics. And it has similarly been argued that the Russellian paradoxes set non-trivial constraints on the cardinality of the universe. Moreover, it has been thought that variants of the Russellian arguments place strict limits on the granularity of properties and propositions. The arguments, however, are not airtight and they invite questions such as the following:

What exactly is the cardinality of the universe?
How many objects might there have been?
Are there strictly more properties than there are objects? Are there strictly more pluralities than objects? Are there more propositions than ways the world might have been? Or do the Russellian arguments show something else entirely?
If not, how are we to make sense of the resulting limitations on fineness of grain?
Do the above questions even make sense?
What are the different forms of the Russell-Myhill paradox, and how should we respond to them?
How, if at all, is the Russell-Myhill paradox related to Kaplan’s paradox?
Does Kaplan’s paradox raise a serious problem for possible worlds semantics?

Abstracts

Josh Dever, “Quantity Without Quantities” (University of Texas, Austin/St Andrews)

I explore the prospects for a contingentist combination of ZFCU with an axiom of uelement set existence with a strong plenitude principle that it is possible for the urelements to be absolutely infinite in number, with the combination depending crucially on the thought that the size of the set-theoertic universe is modally variable. The resulting picture connects the iterative conception of set to a grounding story on which varying numbers of urelements can drive varying heights to the iteration. Along the way I consider some points about the content of large cardinal hypotheses across such modal variation, and dabble a bit in multisets and sequences as alternative focuses of grounding principles and quantity representatives.

Peter Fritz (University of Oslo), “A Purely Recombinatorial Puzzle”

A new puzzle of modal recombination is presented which relies purely on resources of first-order modal logic. It shows that naive recombinatorial reasoning, which has previously been shown to be inconsistent with various assumptions concerning propositions, sets and classes, leads to inconsistency by itself. The context sensitivity of modal expressions is suggested as the source of the puzzle, and it is argued that it gives us reason to reconsider the assumption that the notion of metaphysical necessity is in good standing.

Øystein Linnebo (University of Oslo), “Cantor countered”

By a higher-order generalization of Cantor’s theorem, we appear able to prove that any given plurality has more subpluralities than it has members. After outlining some puzzles to which the generalization gives rise, I explore the prospects for blocking the generalization by restricting the higher-order comprehension schemes. The restrictions in question are motivated by a view of the universe as “open-ended”— in a sense that generalizes the ancient notion of potential infinity.

Lavinia Picollo, MCMP Munich, "The expressive function of truth".

It is often said that the truth predicate serves a logico-expressive function, namely, it allows for the expression of so-called `infinite conjunctions'. This function prompts the formulation of logics or formal theories of truth. We argue that what principles these systems should validate depends on what it means for an infinite conjunction to express or stand in for all its `conjuncts'. We examine two accounts for this phenomenon that are available in the literature and show them to be substantially flawed. We put forward a new approach and discuss whether classical or non-classical logics are to be preferred as basis for theories of truth. We also propose a reconceptualisation of deflationism, according to which the meaning of truth in natural language is largely irrelevant for the deflationist's choice of a truth theory. Furthermore, we discuss a similar approach to the class-theoretic paradoxes and suggest that we should be deflationists about classes as well.

Graham Priest (CUNY), Paradoxical Propositions

This paper concerns two paradoxes involving propositions. The first is Russell's paradox from Appendix B of The Principles of Mathematics, a version of which was later given by Myhill. The second is a paradox in the framework of possible worlds, given by Kaplan. This paper shows a number of things about these paradoxes. First, we will see that, though the Russell/Myhill paradox and the Kaplan paradox might appear somewhat different, they are really just variants of the same phenomenon. Though they do this in different ways, the core of each paradox is to use the notion of a proposition to construct a function, f, from the power set of some set into the set itself. Next we will see how this paradox fits into the Inclosure Schema. Finally, I will provide a model of the paradox in question, showing its results to be non-trivial, though inconsistent.

Agustin Rayo (MIT/Oslo), "Quantification and Realism"

I argue for a facts-first conception of reality, according to which there are many different ways of carving logical space into objects.

Stewart Shapiro (Ohio State University)

"Ontology in mathematics (and beyond): the case of points" (joint work with Geoffrey Hellman)

It is probably safe to say that the prevailing views on ontology and ontological commitment trace to Quine’s “On what there is”. The slogan is “To exist is to be the value of a bound variable”. One can thus speak of the ontology of a mathematical theory, and the commitments of a mathematician, once we get straight on what it is to assert, adopt, accept, … a mathematical theory. The purpose of the present exercise is to see how the broadly Quinean themes play themselves out, given some plausible assumptions about mathematics—a broadly structuralist perspective. There are some ramifications concerning the more mathematized (or structural) aspects of ordinary, scientific theories. The main case study concerns points in space or space-time.

Gabriel Uzquiano (USC/St Andrews), A puzzle for Cantorian reasoning

Cantorian reasoning is often supposed to establish certain cardinal inequalities in logic and metaphysics. It tells us that there are more propositions than possible worlds, more Fregean concepts than objects, more mereological fusions than atoms, etc. Some of these cardinal inequalities compare objects of different sorts, e.g., there are more mereological fusions than atoms. Other inequalities, however, concern cross-categorical cardinal comparisons, e.g., there are more Fregean concepts than objects and there are more pluralities than objects – given more than one object. The talk will be particularly concerned with the latter uses of Cantorian reasoning. A close look at them may suggest some distance between the purely formal statement of the relevant generalization of Cantor’s theorem on which they rely and the informal gloss they receive when deployed in Cantorian reasoning. The purpose of this talk is to bridge the gap between the two.

Organizer

Øystein Linnebo

Workshop: Higher-Order Metaphysics

Time and place: June 4, 2016 – June 5, 2016, Georg Morgenstiernes hus, room 652 (CSMN)

Higher-order logic, with its quantifiers binding variables in sentence position and predicate position, provides an attractive way of formalizing talk of propositions, properties and relations in metaphysics. In such a formalization, these entities are naturally taken to be extra-linguistic just like the referents of singular terms. The topic of the workshop is the metaphysics of propositions, properties and relations, understood in such an extra-linguistic way, whether formulated in higher-order or first-order terms.

In particular, the workshop will focus on how finely these entities are individuated, asking for informative necessary and/or sufficient conditions for propositions, properties or relations to be identical. For example, do any two truth-functionally equivalent sentences express the same proposition? This issue might by summed up as the following question: how fine-grained is reality? Other key questions include:

Should we formalize talk of propositions, properties and relations using first- or higher-order quantifiers?
How should one respond to the paradoxes of propositions and properties due to Russell, Myhill and Prior, as well as Frege's paradox of the concept horse?
How does the fineness of grain of propositions, properties and relations relate to other metaphysical vocabulary, such as "metaphysically necessary", "fundamental", "ground" and "real definition"?
What can philosophers learn about the metaphysics of propositions, properties and relations from work in logic and computer science, e.g., on algebraic models for non-classical logics?
What applications does the metaphysics of propositions, properties and relations have within metaphysics, in philosophy, and outside of philosophy, and how do these applications inform it?

Keynotes

Cian Dorr (New York University)
Timothy Williamson (University of Oxford)

Contributed Talks

The following contributed talks were selected from anonymized submissions to an open call for papers:

Andrew Bacon & Jeffrey Sanford Russell (University of Southern California): The Logic of Opacity
Stephan Leuenberger (University of Glasgow): The Consistency of Non-reductive Supervenience Theses
Jon Erling Litland (University of Texas at Austin): Exact Necessitation
Robert Schwartzkopff (University of Hamburg): The Misconception of Number(word)s as Object(word)s
Alexander Skiles (Université de Neuchâtel): Grounding, Essence, and Identity (joint work with Fabrice Correia)
Dustin Tucker (Colorado State University): Hyperintensionality and the Paradox of the Knower

In connection with this workshop, a workshop on "Cardinality, Worlds and Paradox" will take place in Oslo on 7-8 June 2016.

Organizer

Peter Fritz

2015

The Philosophical Significance of Conceptual History

Time and place: June 22, 2015 – June 23, 2015, St Andrews

Organizer

Herman Cappelen and David Plunkett

2013

Workshop on Haslanger on Ameliorative Projects

Time and place: Oct. 14, 2013 – Oct. 15, 2013, St Andrews

Published Jan. 8, 2024 3:08 PM - Last modified Jan. 9, 2024 10:36 AM

Conferences

2022

Engineering the Concept of Collection

Further question may include

Program

20th June, Georg Morgenstiernes hus, Room 652 - (all times are in CET)

21st June, Georg Morgenstiernes hus, Room 452

Abstracts

Carolin Antos: Engineering the concept of set in practice - a case for concept pluralism?

Neil Barton: Engineering Set-Theoretic Concepts

Tim Button: MOON theory: Mathematical Objects with Ontological Neutrality

Herman Cappelen and Øystein Linnebo: Engineering the concept of collection: introductory remarks

Laura Crosilla: On Weyl’s predicative concept of set

Kentaro Fujimoto: Plural, infinity, and impredicativity

Luca Incurvati: Engineering the concept of set and engineering the concept of objectified property

Stewart Shapiro: Engineering the concept of set and engineering the concept of objectified property

Organizers

Communicating with AI Workshop

Speakers

Program

Sunday, June 19th, 2022

Monday, June 20th, 2022

2021

Critical views of Infinity

Speakers:

Schedule

Tuesday 15 of June 2021 (Oslo time)

Wednesday 16 of June 2021

Abstracts

Thierry Coquand

Laura Crosilla

Mirja Hartimo

Reinhard Kahle

Øystein Linnebo

Michael Rathjen

Dag Normann and Sam Sanders

Wilfried Sieg

Organizer

2021

Varieties of Potentialism

Program (time displayed in CEST)

Abstracts

Title: Potentialism and ultimate V"

Title: Modal model theory as mathematical potentialism

Title: Intuitionism and Potentialism about Real Numbers

Title: Two kinds of potential domains: some logical and historical remarks

Organizer

Taking Stock Workshop (online)

*In the process of being reorganized* Workshop Conceptual Engineering: The Role and Nature of Functions

Organizer

2019

Predicativity and the notions of stability and invariance

Organizer

Workshop: Conceptual analysis, conceptual engineering and experimental philosophy

Talk by Sorin Bangu

Workshop: Self-blame and Moral Responsibility

20th of September

21st of September

In View of Mathematical Thought and its Objects

Program

Saturday 10 August

Sunday 11 August

Organizer

Workshop on Difficulties in Communicating Online

Organizer

Workshop on Speech Act Engineering

Organizer

One day workshop - ConceptLab taking stock

Schedule

Workshop: Linguistic Meaning: Metaphysics, Epistemology, and Ethics, in Oxford

Linguistic Meaning: Metaphysics, Epistemology and Ethics Philosophy Conference

Invited Speakers

Organizer

Workshop on Mutual Understanding

Friday, March 29, Connecticut Hall, Faculty Room

Saturday, March 30, Connecticut Hall, Faculty Room

Formal concepts mini-workshop

Schedule

Abstracts

“Sets as Structures”, Sam Roberts

In the process of being reorganized Workshop Conceptual Engineering: The Role and Nature of Functions