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Mark Jago

Professor of Philosophy, Faculty of Arts

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Biography

My first research was in Nottingham's computer science department, working on how artificially intelligent (AI) agents should go about revising their beliefs upon learning new information. After my PhD, I moved to Macquarie in Sydney, where I worked on the philosophy and logic of resource-bounded reasoning. (That's reasoning that's logical and mathematical, but subject to real-world restrictions of time, memory and patience - the kind of reasoning we do when we're trying to work through some difficult problem.)

Whilst in Sydney, I began working on metaphysical questions about truth and about how reality is ultimately made up. I now work in the philosophy department at Nottingham, writing about truth, knowledge, reasoning and paradox.

For me, the big questions are about how the world ultimately is, and how we can think and know about it. I like to approach these difficult questions by combining the logical, technical approach of mathematics and computer science with the inventiveness of philosophy.

Expertise Summary

I've published and given research talks in the following areas:

  • Metaphysics: Truth and truthmaking, constitution, facts and states of affairs, modality and counterpart theory, existence and absence

  • Epistemology: Knowability, epistemic logic, belief revision

  • Formal and philosophical logic: Modal logic, relevant logic, Fitch's paradox

  • Philosophy of Language: Propositions, vagueness, content, what is said, indexicals, semantic paradoxes

  • Philosophy of Mind: Mental causation, mental content

Teaching Summary

The primary aim of my teaching is to enable students to think clearly and think for themselves; and to learn how to discern arguments and evaluate them logically. I also aim to improve students'… read more

Research Summary

My current research centers around three themes:

​1. Thinking about the impossible

(a) An account of propositions as sets of possible and (non-trivial) impossible worlds. This allows an account of same-saying. It also explains how logically equivalent propositions can be distinct and hence how they can be made true by distinct entities.

(b) An account of epistemic possibility, which is non-trivial in the sense that not every set of sentences represents some epistemic/doxastic possibility, and non-ideal in the sense that some epistemic possibilities are logically impossible. The account can be used to give a semantics for 'knows' and 'believes' (and possibly other psychological attitudes).

I bring this work together in my book, The Impossible (OUP, 2014). A further book on the topic, Impossible Worlds, which I'll co-write with Franz Berto (Amsterdam), is under contract with OUP.

2. The Nature of Truth

This project sets out the metaphysical nature of truth. It seeks to explain the ontological basis of the property being true. Along the way, I'll explain three crucial aspects of truth:

  1. The truth makers: the bits of the world responsible for making truths true (and for making falsehoods false). I develop an account of states of affairs for this purpose.
  2. The truth bearers: the things that are true or false. I argue that propositions do this job, and I develop a metaphysical theory of what they are.
  3. The truthmaking relationship between truthmakers and truthbearers. I give both a metaphysical and a formal logical characterisation of the relationship.

Along the way, I'll develop a response to the liar paradox (and other semantic paradoxes, such as Curry's paradox). The project is primarily metaphysical, but it takes in aspects of philosophy of language (theory of truth, propositions), philosophical logic (the liar paradox) and formal logic (truthmaker entailment).

I present this work in a book, What Truth Is (under contract with OUP).

​3. Making up the world

The metaphysics of making: how a lump of stuff makes up some thing (material constitution); how some parts get together to make a unified whole (composition); whether (and if so, how) bundles of qualities make up a particular.

Selected Publications

  • MARK JAGO, 2018. What Truth Is Oxford University Press. (In Press.)
  • FRANZ BERTO and MARK JAGO, 2019. Impossible Worlds Oxford University Press. (In Press.)
  • MARK JAGO, 2018. From Nature to Grounding. In: RICKI BLISS and GRAHAM PRIEST, eds., Reality and its Structure: Essays in Fundamentality Oxford University Press.. (In Press.)
  • MARK JAGO, 2017. Propositions as Truthmaker Conditions Argumenta: special issue on Thinking the (Im)possible. (In Press.)

The primary aim of my teaching is to enable students to think clearly and think for themselves; and to learn how to discern arguments and evaluate them logically. I also aim to improve students' discussion and presentation skills; and improve their ability to judge whether the conclusions people draw are justified by reasons or are mere opinion. These are highly valuable and transferrable skills, and enable students to function as good citizens beyond university. In my approach, historical and factual information is secondary. It is a means to introduce a wide range of theories and viewpoints to students, but knowledge of it is not a main aim of my teaching.

A key theme in my approach is that students should take responsibility for their own learning. (This is particularly important in the transition from A-level to university-level study.) By this, I mean not only that students must motivate themselves to do enough reading and other independent study; but also that they should form their own opinions about a philosophical argument, and then engage in a process of self-critique and discussion with others.

Current teaching

I'm currently teaching Advanced Logic (3rd year) and Intermediate Logic (2nd year)

Past Research

In my PhD thesis (2006), I developed a logic and modal semantics for modelling rule-based agents (of the type that are being developed in AI for commercial applications) with limited cognitive resources (memory & time in which to reason). I axiomatized the logic and gave a number of proofs: soundness & completeness and a complexity analysis (one problem is in NP, another in PSPACE). For the modal semantics, two particular results are of interest:

- Bisimulation in these models is identical to modal equivalence between states.

- Models have the congruence (Church-Rosser) property.

Future Research

Over the next few years, I'll be working on the following themes:

Metaphysics: Truth and truthmaking, constitution, facts/states of affairs, modality and counterpart theory, existence and absence

Epistemology: Knowability, epistemic logic, belief revision

Formal and philosophical logic: Modal logic, relevant logic, Fitch's paradox

Philosophy of Language: Propositions, vagueness, content, what is said, indexicals, semantic paradoxes

Philosophy of Mind: Mental causation, mental content

  • FRANZ BERTO and MARK JAGO, 2019. Impossible Worlds Oxford University Press. (In Press.)
  • KIT FINE and MARK JAGO, 2019. Logic for Exact Entailment Review of Symbolic Logic. (In Press.)
  • MARK JAGO, 2019. The Truthmaker Account of Propositions. In: CHRIS TILLMAN, ed., The Routledge Handbook of Propositions Routledge. (In Press.)
  • MARK JAGO, 2018. What Truth Is Oxford University Press. (In Press.)
  • MARK JAGO, 2018. From Nature to Grounding. In: RICKI BLISS and GRAHAM PRIEST, eds., Reality and its Structure: Essays in Fundamentality Oxford University Press.. (In Press.)
  • MARK JAGO, 2018. Essential bundle theory and modality Synthese.
  • MARK JAGO, 2018. Knowing How Things Might Have Been Synthese.
  • FRANZ BERTO and MARK JAGO, 2018. Impossible Worlds. In: ED ZALTA, ed., Stanford Encyclopedia of Philosophy 2018
  • MARK JAGO and RICHARD MARSHALL, 2018. The impossible and the real: Interview in 3:AM magazine Available at: <https://www.3ammagazine.com/3am/the-impossible-and-the-real/>
  • MARK JAGO, 2017. Propositions as Truthmaker Conditions Argumenta: special issue on Thinking the (Im)possible. (In Press.)
  • KEN WALLACE and MARK JAGO, 2017. Category mistakes: a barrier to effective environmental management Journal of Environmental Management.
  • HAROLD NOONAN and MARK JAGO, 2017. Modal Realism, Still At Your Convenience Analysis. 77(2), 299–303
  • MARK JAGO, ed., 2016. Reality Making Oxford University Press.
  • MARK JAGO, 2016. Advanced Modalizing Problems Mind. 125(499), 627-642
  • MARK JAGO, 2016. Alethic Undecidability Doesn’t Solve the Liar Analysis. 76(3), 278-283
  • MARK JAGO, 2016. Essence and the Grounding Problem. In: MARK JAGO, ed., Reality Making Oxford University Press. 99–120
  • MARK JAGO, 2016. Introduction. In: MARK JAGO, ed., Reality Making Oxford University Press..
  • MARK JAGO, 2015. Hyperintensional Propositions Synthese. 192(3), 585–601
  • STEPHEN BARKER and MARK JAGO, 2014. Monism and Material Constitution Pacific Philosophical Quarterly. 95(2), 189-204
  • MARK JAGO, 2014. The Impossible: An Essay on Hyperintensionality Oxford University Press.
  • JAGO, M., 2013. The content of deduction Journal of Philosophical Logic. 42(2), 317-334
  • MARK JAGO, 2013. Against Yagisawa’s Modal Realism Analysis. 73(1), 10-17
  • MARK JAGO, 2013. The Problem of Rational Knowledge Erkenntnis.
  • MARK JAGO, 2013. Recent Work in Relevant Logic Analysis. 73(3), 526–541
  • PENELOPE MACKIE and MARK JAGO, 2013. Transworld Identity The Stanford Encyclopedia of Philosophy.
  • MARK JAGO, 2013. Impossible Worlds Nous.
  • MARK JAGO, 2013. The Cost of Truthmaker Maximalism Canadian Journal of Philosophy. 43(4), 460–474
  • MARK JAGO, 2013. Are Impossible Worlds Trivial?. In: VIT PUNCOCHAR and PETR SVARNY, eds., The 2012 Logica Yearbook Filosophia.
  • JAGO, M. and BARKER, S., 2012. Being positive about negative facts Philosophy and Phenomenological Research. 85(1), 117-138
  • JAGO, M., 2012. The truthmaker non-maximalist's dilemma Mind. 121(484), 903-918
  • MARK JAGO, 2012. Constructing Worlds Synthese. 189(1), 59-74
  • MARK JAGO and RACHAEL BRIGGS, eds., 2012. Special issue of Synthese on ‘Propositions and Same-Saying’ Springer.
  • NOONAN H.W. and JAGO M., 2012. The Accidental Properties of Numbers and Properties Thought. 1(2), 134-40
  • RACHAEL BRIGGS and MARK JAGO, 2012. Introduction to ‘Propositions and Same-Saying’ Synthese. 189(1), 1–10
  • MARK JAGO, 2012. The Problem with Truthmaker-Gap Epistemicism Thought. 1(4), 320–329
  • RACHAEL BRIGGS and MARK JAGO, eds., 2012. Propositions and Same-Saying: Special issue of Synthese
  • JAGO, M., 2011. Setting the facts straight Journal of Philosophical Logic. 40(1), 33-54
  • JAGO, M., 2010. Joe Salerno (ed): New Essays on the Knowability Paradox JOURNAL OF LOGIC LANGUAGE AND INFORMATION. VOL 19(NUMBER 3), 383-387
  • JAGO, M., 2010. Closure on knowability ANALYSIS -OXFORD-. VOL 70(NUMBER 4), 648-659
  • MARK JAGO, 2010. Relevant Logic. In: J. WILLIAMSON and F. RUSSO, eds., Key Terms in Logic 61–62
  • MARK JAGO, 2010. Nonmonotonic Logic. In: J. WILLIAMSON and F. RUSSO, eds., Key Terms in Logic 52–54
  • 2010. In: J. WILLIAMSON and F. RUSSO, eds., Key Terms in Logic Paraconsistent Logic.
  • MARK JAGO, 2010. Review of Joe Salerno (ed.), New Essays on the Knowability Paradox Journal of Logic, Language & Information. 19(3), 383–387
  • JAGO, M., 2009. The Conjunction and Disjunction Theses MIND -OXFORD-. VOL 118(NUMB 470), 411-416
  • JAGO, MARK, 2009. Logical Information and Epistemic Space Synthese. 167(2),
  • JAGO, M., 2009. Epistemic Logic for Rule-Based Agents JOURNAL OF LOGIC LANGUAGE AND INFORMATION. VOL 18(NUMBER 1), 131-158
  • MARK JAGO, 2009. Resources in Epistemic Logic. In: J-Y. BÉZIAU and A. COSTA-LEITE, eds., Dimensions of Logical Concepts 55. Coleção CLE. 11–33
  • MARK JAGO, 2009. Review of Jonathan A. Waskan, Models and Cognition Mind. 118, 220–225
  • ALECHINA, N., JAGO, M. and LOGAN, B., 2008. Preference-based belief revision for rule-based agents Synthese. 165(2), 159-177
  • MARK JAGO, 2008. Narrow Content and Rationality. In: MICHAL PELIŠ, ed., The 2007 Logica Yearbook Filosophia. 43–54
  • MARK JAGO, 2008. Bourne’s Negation: No Equivocation The Reasoner. 2(1), 7
  • MARK JAGO, 2008. Modal Logic The Reasoner. 2(2), 11
  • ALECHINA, A and JAGO, M. AND LOGAN, B., 2007. Belief Revision for Rule-Based Agents. In: VAN BENTHEM, J and JU, S. AND VELTMAN, F., eds., A Meeting of the Minds: Proceedings of the Workshop on Logic, Rationality and Interaction, Beijing, 2007 College Publications. 99-113
  • ALECHINA,N., BERTOLI, P., GHIDINI, C., JAGO,M., LOGAN,B. and SERAFINI,L., 2007. Model-checking space and time requirements for resource-bounded agents. In: EDELKAMP, S. and LOMUSCIO, A., eds., Model-Checking and Artificial Intelligence. 4th Workshop, MoChArt IV, Riva del Garda, Italy, August 2006. Revised Selected and Invited Papers. 4428. Springer. 19-35
  • MARK JAGO, 2007. Hintikka and Cresswell on Logical Omniscience Logic & Logical Philosophy. 15(4), 131–158
  • MARK JAGO, 2007. Review of Ross Brady, Universal Logic Studia Logica. 87(2), 359–362
  • ALECHINA, N., JAGO, M. and LOGAN, B., 2006. Modal logics for communicating rule-based agents In: Proceedings of the 17th European Conference on Artificial Intelligence (ECAI 2006). 322-326
  • ALECHINA,N., BORDINI,R., HUBNER,J., JAGO,M. and LOGAN,B., 2006. Automating Belief Revision for AgentSpeak. In: BALDONI,M. and ENDRISS, U., eds., Declarative Agent Languages and Technologies IV, 4th International Workshop, DALT 2006, Selected, Revised and Invited Papers 4327. Springer. 61-77
  • NATASHA ALECHINA, P. BERTOLI, C. GHIDINI, MARK JAGO, B. LOGAN and L. SERAFINI, 2006. Verifying Space and Time Requirements for Resource-Bounded Agents In: Proceedings of the 5th International Joint Conference on Autonomous Agents and Multi-Agent Systems.
  • N. ALECHINA, R. BORDINI, J. HÜBNER, MARK JAGO and B. LOGAN, 2006. Belief Revision for AgentSpeak Agents In: Proceedings of the 5th International Joint Conference on Autonomous Agents and Multi-Agent Systems. 1288–90
  • MARK JAGO, 2006. Rule-Based and Resource-Bounded: A New Look at Epistemic Logic In: Proceedings of the Workshop on Logics for Resource Bounded Agents at ESSLLI 06.
  • MARK JAGO, 2006. Modelling Resource-Bounded Reasoning Artificial Intelligence & the Simulation of Behaviour Quarterly. 124, 5
  • MARK JAGO, 2006. Imagine the Possibilities: Information without Overload Logique et Analyse. 46(196), 345–71
  • 2006. Truth. In: N. GOULDER, A.C. GRAYLING and A. PYLE, eds., Encyclopedia of British Philosophy Continuum. 695–697
  • MARK JAGO, 2006. Consciousness. In: N. GOULDER, A.C. GRAYLING and A. PYLE, eds., Encyclopedia of British Philosophy Continuum. 1059–1060
  • MARK JAGO, 2006. Fatalism. In: N. GOULDER, A.C. GRAYLING and A. PYLE, eds., Encyclopedia of British Philosophy Continuum. 3200–3202
  • MARK JAGO, 2006. Answers to 5 questions. In: V. HENDRICKS and J. SYMONS, eds., Masses of Formal Philosophy Automatic Press/VIP. 76–82
  • MARK JAGO, 2006. Pictures and Nonsense Philosophy Now. 58, 7–9
  • ALECHINA,N., JAGO,M. and LOGAN,B., 2005. Resource-Bounded Belief Revision and Contraction In: Declarative Agent Languages and Technologies III, Third International Workshop, DALT 2005, Utrecht, The Netherlands, July 25, 2005, Selected and Revised Papers. 141-154
  • MARK JAGO, 2005. Modelling Assumption-Based Reasoning Using Contexts In: Proceedings of the Contextual Representation and Reasoning Workshop held at CONTEXT 05.
  • ALECHINA,N., MARK JAGO and LOGAN,B.S., 2004. A complete and decidable logic for resource-bounded agents In: Proceedings of the Third International Joint Conference on Autonomous Agents and Multi-Agent Systems (AAMAS 2004). 606-613
  • MARK JAGO, 2004. Timed Reasoning Logics In: Proceedings of the Logic and Communication in Multi-Agent Systems Workshop at ESSLLI 04.
  • MARK JAGO, 2004. Belief Revision for Resource Bounded Agents In: Proceedings of the 2nd European Workshop on Multi-Agent Systems. 345–53
  • NATASHA ALECHINA, MARK JAGO and BRIAN LOGAN, 2004. Modelling Communicating Agents in Timed Reasoning Logics. In: ALFERES and LEITE, eds., Logics in Artificial Intelligence Lecture Notes in Artificial Intelligence 3225. Springer. 95–107
  • CORAZZA, EROS and JAGO, MARK, 2003. Indexicals, Fictions, and Ficta Dialectica. 52(2), 121-136
  • MARK JAGO, 2003. Discourse Context and Indexicality. In: CARBONELL and SIEKMANN, eds., Modelling and Using Context Lecture Notes in Artificial Intelligence 2680. Springer. 356–368

Department of Philosophy

University of Nottingham
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Nottingham, NG7 2RD

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