Project Work

Recent talks by project members:


Oxford, conference on the philosophical significance of verbal disputes, May 2015 “Real representation”

Ratio conference on indeterminacy and ethics, April 2015 “Indeterminacy, Angst and Ethics”.

Leeds NatRep workshop on Radical Interpretation: “The grain and ground of doxastic space”

Stockholm, November 2014. “Representations of an external world”

Uppsala, November 2014. “Rational illogicality”

York, Mind Network Meeting, October 4th 2014. “Representations of an external world”.

Kings College London, departmental colloquium, September 2014. “Representations of an external world”

Munich, conference on Logical Norms. September 2014. “Rational illogicality”

Leeds, inaugural lecture “Representations of an external world”.

Duke University, workshop on Belief. May 2014. (Comments on Fitelson’s work on accuracy and partial belief).

Hamburg, conference on Conditionals. April 2014. “Decisions, suppositions and conditionals” (drawing on joint work with Daniel Elstein).

Leeds centre for ethics and metaethics, March 2014. “Indeterminacy and choice”.

Leeds undergraduate philosophy society, February 2014. “Frege”

Leeds Centre for metaphysics and mind, January 2014 “Rational illogicality”.

Leeds Representation seminar, “Radical Interpretation Revisited” (three seminars).

Leeds, NatRep workshop on conditional thinking. “Suppositions and Decisions” (joint work with Daniel Elstein).

Cambridge, Trinity Undergraduate Philosophy Society, January 2014. “Semantic bookkeeping and semantic teleology”

Reading, departmental colloquium, January 2014. “Rational illogicality”

Princeton, departmental colloquium, November 2013. “Rational illogicality”

Syracuse, colloquium, November 2013. “Semantic bookkeeping and semantic teleology”.

Leeds Centre for metaphysics and mind, November 2014 “Semantic bookkeeping and semantic teleology”.

Oxford, philosophy of mathematics seminar, November 2013. “Rational illogicality”

Edinburgh, departmental colloquium, October 2013. “Semantic bookkeeping and semantic teleology”

St Andrews, departmental colloquium, October 2013. “Rational illogicality”

Aberdeen, research seminar, October 2013. “Mindmaking”

Sydney, July 2013. “Inconceivable Indeterminacy”

ANU, Thursday seminar, July 2013. “Mind-Making”

Brisbane AAP, July 2013. “Two kinds of logical norm”.

Nottingham, departmental colloquium, February 2013. “Intuitionism, indeterminacy and inconstancy”

Glasgow, departmental colloquium, January 2013. “Decision making under indeterminacy”

Aberdeen, workshop for Crispin Wright, December 2012. “Intuitionism, indeterminacy and inconstancy”.

Oxford, Jowett Society, November 2012. “Reference magnetism”.


2015 APA Pacific Division Conference. “Thoughts about specific non-existent objects: Crane’s Objects of Thoughts”

Centre for Metaphysics and Mind, Leeds “In what sense are mental files diachronic?”

UC Davis, “Singular thought as a cognitive kind”.

University of Nottingham departmental seminar “Cognitivism, mental files and singular thought”.

University of Illinois, Chicago, “Cognitivism, mental files and singular thought”.

University of Sheffield, “Reference, co-reference and singular thought”.

Symposium on the work of Francois Recanati, University of St Andrews, “Epistemically rewarding relations and mental files”.

Leeds philosophy department colloquium, March 2014, “Against the Mental Files Conception of Singular Thought.”

Philosophy of Language in the UK Conference (PLUK), March 2014, “On the Supposed Connection between Singular Thought and Proper Names.”

Reading philosophy department colloquium, November 2014, “Cognitivism, Significance and Singular Thought”

Edinburgh epistemology group, October 2014, “Cognitivism, Significance and Singular Thought.”


Diachronic rationality workshop, Wisconsin, Madison, summer 2015. “Rationality over time”

Epistemic utility of imprecise credences, Bristol, 2015. “Chancy accuracy and imprecise credences”.

Centre for Metaphysics and Mind, Leeds, 2015. “Mental metasemantics and rationality”.

Epistemic consequentialism conference, Konstanz, summer 2015, “Accuracy or Coherence?”

Choice group, LSE, 2015, “Accuracy or Coherence?”

Eastern APA, Philadelphia, 2014. “Accuracy or Coherence?”

Epistemic consequentialism workshop, LSE, 2014, “Accuracy or Coherence?”

USC Formal Epistemology Workshop, June 2014, “Accuracy or Coherence?”

St Louis Annual Conference on Reasons and Rationality, May 2014, “Imprecise Evidence without Imprecise Credences,”

University of Hamburg, April 2014, “The ‘If P, Ought P’ Problem.”

University of Bristol, March 2014, “Accuracy or Coherence?”

Philosophy of Language in the UK Conference (PLUK), March 2014, “The ‘If P, Ought P’ Problem.”

St Andrews Normative Language Workshop, November 2013, “Subjective ‘Ought’.”


Second European Workshop on Non-Categorical Thinking (Turin), September 2016, “Modal Plural Logic: A plea for moderation”.

Kings College London, October 2016, “Against Serious Ontology”.

Third French Workshop on the Philosophy of Mathematics (Marseilles), November 2016, “Linguistic Reinterpretation and Indefinite Extensibility”.

Centre for Metaphysics and Mind, University of Leeds, February 2017, “The Limits of Ontology”.

Reasoning Club Annual Conference (Turin), May 2017, “Frege’s theorem in plural logic”.


University of York departmental colloquium,  November 2016, “Words by Convention”.

Centre for Metaphysics and Mind, University of Leeds, October 2016, “Words by Convention”.

Workshop on The nature and understanding of sense (Leeds), June 2016, “What is known; what is thought; what is said”.

Centre for Metaphysics and Mind, University of Leeds, “Words. Words. Words”

University of Leeds, department colloquium, Nov 2015  “Understanding logical expressions”


LSE departmental colloquium, 2016, ‘Measuring the Beliefs of the Frequently Irrational’

National Uni of Singapore, 2016, ‘Measuring the Beliefs of the Frequently Irrational’

Centre for Metaphysics and Mind, University Leeds, 2016, ‘Impossible Worlds and Partial Beliefs’


Pluralism Workshop 3, Cogito Research Centre, University of Bologna, Italy, 19-21 December, 2016, Workshop on his thesis, including a reading group on “Expressivism and Moral Truth: Or, Why the Expressivist Can Only Go So Far Wrong”, and presentations of “Truth: Explanation, Success, and Coincidence” and “Infinite Liars are Better than One”.

Truth: Deflationism and Beyond, University of Sassari, Italy, 23-24 September 2016, “Truth: Explanation, Success, and Coincidence”

Pluralisms Week at Yonsei University, South Korea, 11-20 June 2016 “OMG?!  Truth Pluralism, Mixing Problems, and the One-Many Gambit”

5thAnnual Graduate Conference: Logic and Language (University of Calgary, Canada, May, 2016,  “OMG?!  Truth Pluralism, Mixing Problems, and the One-Many Gambit”

Language @ Leeds Seminar, University of Leeds, May 2015, “OMG?!  Truth Pluralism, Mixing Problems, and the One-Many Gambit”

Centre for Metaphysics and Mind, University of Leeds, February 2017, “Infinite Liars are Better than One”

Language and Metalanguage, Logic and Meta-Logic; Revisiting Tarski’s Hierarchy at Universite Catholique de Louvain, Belgium, May 2016, “Infinite Liars are Better than One”

Centre for Ethics and Metaethics, University of Leeds, January 2017, “Expressivism and Moral Truth: Or, Why the Expressivist Can Only Go So Far Wrong”

British Postgraduate Philosophy Association Annual Conference, University of Leeds, September 2014, “Philosophical Analysis and Default Pluralism”


“Trends in Proof Theory”, satellite meeting of the 2015 Jahrestagung der Deutschen Mathematiker-Vereinigung, Hamburg, (Germany), September 2015, “Predicativity: between Philosophy of Mathematics and Proof Theory,”


The Metaphysics of Words, Leeds University, June 2017, “The real problem with the form-theoretic view of words”.

Work on project themes by members of the project:


Eligibility and Inscrutability“; Philosophical Review 116(3): 361-399 (July 2007) Penultimate draft
Interpretationist metasemantic theories are attractive, but a long-standing concern about them is that they don’t pin down the meaning of words precisely enough—crazily permuted schemes of reference are just as good, by interpretationist lights, as sensible interpretations. Lewis’s appeal to “eligibility” as an extra metasemantic constraint is supposed to fix this. I make the case that his appeal to eligibility is rooted in a particular understanding of the theoretic virtue of simplicity. And I present a new challenge for this approach: if the world is sufficiently metaphysically complex, then crazy reference-schemes will determinately beat sensible interpretations.

“The Price of Inscrutability”; in Nous vol 42(4): 600-641 (2008). Penultimate Draft
There are many “inscrutability arguments” on the market, designed to show that (at least given certain formulations of what fixes meaning) the meanings of our words are much less settled than we naturally take them to be. When should we regard such a result as a bug, rather than a feature, of a metaphysics of meaning? This paper takes stock of the options, and develops in detail one particular problem: the inscrutability of sameness-of-reference across contexts. A case is made that such a result would undermine the epistemology of deductive inference.

The Inscrutability of Reference (PhD thesis, University of St Andrews, 2006).
The thesis explores arguments for the inscrutability of reference, the kind of theories for which it is a problem, and potential variations and patches that would avoid it. Along the way, we look at how one should formulate inscrutability/indeterminacy theses and what the costs of accepting inscrutability would be. Material from the thesis is included in “Eligibility and Inscrutability”, “The price of inscrutability” (above) and “Gavagai again” (below).

“Requirements on reality” in Grounding and Explanation Correira and Schneider, eds. (CUP, 2012)
If we want to avoid the costs of radical revisionism, we better say that the vast majority of common sense and scientific judgement is more-or-less true. But with a metaphysical hat on, we might want to say that reality is fairly austere. These desiderata appear to conflict—the first tells us that there are numbers and compound material things; the second may tell us that these are no part of reality. One contemporary reconciliation is to endorse a multifaceted metaphysics: with some things existing fundamentally, others derivatively, grounded by but not part of the fundamental level. I look at a more traditional reconciliationist project, where (one way or another) we say that the acknowledged truth of the existence of compound things (a table, say) makes only minimal demands on reality (that there be things arranged tablewise). The paper examines classic and contemporary ways of making sense of the key notion of “reality-requirements”.

“Fundamental and derivative truths” Mind 119(473): 103-141 (January 2010). Penultimate Draft
This paper develops in detail my own preferred take on the notion of the ‘reality requirements’ of a given sentence or proposition. I emphasize that what reality-requirements a sentence enjoys is a contingent feature of it, and one that counterfactually varies with what truth-conditions it has. We shouldn’t leave such features and correlations brute and unexplained: part of the task of metasemantics should be to say how ontological commitments/reality requirements get fixed. I discuss how an interpretationist metasemantics can do this job, in such a way that sentences with the same truth-conditions may nevertheless have different reality requirements, if they inhabit worlds with different ontologies.

Lewis on eligiblity and reference (recent draft)—for volume on David Lewis, Loewer and Schaffer eds.
This survey piece describes Lewis’s version of interpretationism, the role of “eligibility” within it, and ways in which we may revise our theory of eligibility to make the whole package credible. Options considered include an expansive metaphysics, taking comparative (rather than perfect) naturalness as the primitive notion, and adopting a deflationary, rather than metaphysics-rich, account of eligibility.

Reference magnets (draft.)
This paper (which an extended version of “Lewis on reference and eligibility”) additionally includes discussion of Field’s notion of a conventional metasemantics—the idea that even if reference is determinate, there may be alternative ways to theorize about semantic facts (for example, using permuted reference schemes) that would serve all the same explanatory purposes as reference does. These distinctions are motivated and applied to Lewis’s theory, in an attempt to articulate the sense that there’s something mysterious or unexplanatory about the notion of “reference magnetism” he works with. 

Davidson on Reference” forthcoming in Companion to Donald Davidson, Ludwig and Lepore eds.
I take an overview of the place of Reference in Donald Davidson’s philosophy of language. This includes its role in T-theories, his recommendation that we take permutation arguments at face value and accept that reference is inscrutability, and how to best understand his appeals to instrumentalism as a way of understanding the role of a theory of reference. The ways in which reference might be involved in explanations is examined.

Permutations and Foster problems: two puzzles or one?“; Ratio Vol XXI(1): 91-105 (March 2008). Penultimate draft
I argue that Foster problems and permutation arguments stand and fall together. The puzzles they pose have similar presuppositions; and what solves one puzzle will likely also solve the other. Davidson himself seems to regard Foster problems as something he could and can block; while permutation arguments go through and establish  the inscrutability of reference. I argue that this is an unsustainable package.

“Gavagai again”; Synthese 164(2): 235-259 (September 2008). Penultimate draft.
Quine’s “Gavagai” examples are perhaps the most discussed version of (limited) inscrutability of reference. I relate them to contemporary discussion of continuant vs. counterpart theories, and use this to formulate systematic interpretations of gavagai-talk. This affords a new perspective on the source of some old worries for Quine, which can be traced to some limitations of counterpart theory; it also means we can see Quine’s inscrutability thesis as a challenge to contemporary metaphysical theories of persistence—why think there’s a fact of the matter which view is correct?

Lewis on reference and eligibility” in Companion to David Lewis, Loewer and Schaffer, eds (2015).

Vagueness as indecision” in Proceedings of the Aristotelian Society, Supplementary Volume (2016)

Angst, indeterminacy and conflicting values.” in Ratio Volume 29, Issue 4 December 2016

“Representational Scepticism: The Bubble Puzzle” ; Philosophical Perspectives Volume 30, Issue 1 (December 2016)

Indeterminate Oughts“. Ethics, 127. pp. 645-673. (April 2017)

Rational illogicality“. Australasian Journal of Philosophy. (forthcoming; accepted April 2017)

“Normative Reference Magnets” conditionally accepted at Phil Review 


“Subject ‘Ought'” Ergo 2015 

“Epistemic expansions” Res Philosophica 2015

“Ecumenical Expressivism Ecumenicized: comments on Ridge’s Impassioned Belief” Analysis Reviews 2015

“Deontic modals” chapter in forthcoming Routledge Handbook of Metaethics. 

“Don’t Stop Believing”. Canadian Journal of Philosophy (2015)

“The ‘If P, ought P’ problem” Pacific Philosophical Quarterly, 2014.


Mental Files and Singular Thought, edited volume with OUP.

“Against the mental files conception of singular thought” (2014) Review of Philosophy and Psychology.

“Cognitivism, Significance and Singular Thought”, The Philosophical Quarterly 66:263 (2016),


Leckie, G. and Williams, R. “Words by Convention” invited for Oxford Studies in Philosophy of Language ed Sosa, D. and LePore, E.


“Probabilism, Representation Theorems, and Whether Deliberation Crowds out Prediction”, forthcoming in Erkenntnis accepted June 2016

‘A representation theorem for frequently irrational agents’, forthcoming in Journal of Philosophical Logic


Collective Intentionality X, The Hague, 2016, ‘Social Conventions and Problems of Underdetermination’.

The Normativity of Logic, Bergen, 2017, ‘Treating Logic Expressively: Normativity and Exceptionality’.


“Predicativity and Feferman”, forthcoming in G. Jӓger and W. Sieg (eds.), Feferman and Foundations, Springer’s book series “Outstanding Contributions to Logic”


“Truth: explanation, success, and coincidence” forthcoming in Philosophical Studies


“A note on Uzquiano’s ‘Varieties of Indefinite Extensibility'” forthcoming in Notre Dame Journal of Formal Logic. (Pre-print)

“Representing Generality” – arguing that inferentialists can respond well to concerns about meaning indeterminacy for quantifiers.

“Flat Logicism” – developing a version of neo-Fregeanism about arithmetic within plural logic.

“Tuples all the way down?” – addressing a concern about the legitimacy of introducing reference to pairs by abstraction.

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