•  528
    Alethic undecidability doesn’t solve the Liar
    Analysis 76 (3): 278-283. 2016.
    Stephen Barker presents a novel approach to solving semantic paradoxes, including the Liar and its variants and Curry’s paradox. His approach is based around the concept of alethic undecidability. His approach, if successful, renders futile all attempts to assign semantic properties to the paradoxical sentences, whilst leaving classical logic fully intact. And, according to Barker, even the T-scheme remains valid, for validity is not undermined by undecidable instances. Barker’s approach is inno…Read more
  •  277
    The Impossible: An Essay on Hyperintensionality
    Oxford University Press. 2014.
    Mark Jago presents an original philosophical account of meaningful thought: in particular, how it is meaningful to think about things that are impossible. We think about impossible things all the time. We can think about alchemists trying to turn base metal to gold, and about unfortunate mathematicians trying to square the circle. We may ponder whether God exists; and philosophers frequently debate whether properties, numbers, sets, moral and aesthetic qualities, and qualia exist. In many philo…Read more
  •  1506
    The Problem of Rational Knowledge
    Erkenntnis (S6): 1-18. 2013.
    Real-world agents do not know all consequences of what they know. But we are reluctant to say that a rational agent can fail to know some trivial consequence of what she knows. Since every consequence of what she knows can be reached via chains of trivial cot be dismissed easily, as some have attempted to do. Rather, a solution must give adequate weight to the normative requirements on rational agents’ epistemic states, without treating those agents as mathematically ideal reasoners. I’ll argue …Read more
  •  81
    Resource-bounded belief revision and contraction
    In P. Torroni, U. Endriss, M. Baldoni & A. Omicini (eds.), Declarative Agent Languages and Technologies III, Springer. pp. 141--154. 2006.
    Agents need to be able to change their beliefs; in particular, they should be able to contract or remove a certain belief in order to restore consistency to their set of beliefs, and revise their beliefs by incorporating a new belief which may be inconsistent with their previous beliefs. An influential theory of belief change proposed by Alchourron, G¨ardenfors and Makinson (AGM) [1] describes postulates which a rational belief revision and contraction operations should satisfy. The AGM postulat…Read more
  •  997
    Constructing worlds
    Synthese 189 (1): 59-74. 2012.
    You and I can differ in what we say, or believe, even though the things we say, or believe, are logically equivalent. Discussing what is said, or believed, requires notions of content which are finer-grained than sets of (metaphysically or logically) possible worlds. In this paper, I develop the approach to fine-grained content in terms of a space of possible and impossible worlds. I give a method for constructing ersatz worlds based on theory of substantial facts. I show how this theory overcom…Read more
  •  761
    Imagine the possibilities: information without overload
    Logique Et Analyse 49 (196). 2006.
    Information is often modelled as a set of relevant possibilities, treated as logically possible worlds. However, this has the unintuitive consequence that the logical consequences of an agent's information cannot be informative for that agent. There are many scenarios in which such consequences are clearly informative for the agent in question. Attempts to weaken the logic underlying each possible world are misguided. Instead, I provide a genuinely psychological notion of epistemic possibility a…Read more
  •  47
    Book reviews (review)
    Studia Logica 87 (2-3): 359-362. 2007.
  •  44
    Verifying Space and Time Requirements for Resource-Bounded Agents
    with Natasha Alechina, Piergiorgio Bertoli, Chiara Ghidini, Brian Logan, and Luciano Serafini
    In A. Lomuscio & S. Edelkamp (eds.), Model Checking and Artificial Intelligence, Springer. 2007.
    The effective reasoning capability of an agent can be defined as its capability to infer, within a given space and time bound, facts that are logical consequences of its knowledge base. In this paper we show how to determine the effective reasoning capability of an agent with limited memory by encoding the agent as a transition system and automatically verifying whether a state where the agent believes a certain conclusion is reachable from the start state. We present experimental results using …Read more
  •  1062
    The Conjunction and Disjunction Theses
    Mind 118 (470): 411-415. 2009.
    Rodriguez-Pereyra (2006) argues for the disjunction thesis but against the conjunction thesis. I argue that accepting the disjunction thesis undermines his argument against the conjunction thesis.
  •  636
    Modal Realism, Still At Your Convenience
    with Harold Noonan
    Analysis. 2016.
    Divers (2014) presents a set of de re modal truths which, he claims, are inconvenient for Lewisean modal realism. We argue that there is no inconvenience for Lewis.