•  562
    Two Adaptive Logics of Norm-Propositions
    Journal of Applied Logic 11 (2): 147-168. 2013.
    We present two defeasible logics of norm-propositions (statements about norms) that (i) consistently allow for the possibility of normative gaps and normative conflicts, and (ii) map each premise set to a sufficiently rich consequence set. In order to meet (i), we define the logic LNP, a conflict- and gap-tolerant logic of norm-propositions capable of formalizing both normative conflicts and normative gaps within the object language. Next, we strengthen LNP within the adaptive logic framework fo…Read more
  •  82
    An Inconsistency-Adaptive Deontic Logic for Normative Conflicts
    Journal of Philosophical Logic 42 (2): 285-315. 2013.
    We present the inconsistency-adaptive deontic logic DP r , a nonmonotonic logic for dealing with conflicts between normative statements. On the one hand, this logic does not lead to explosion in view of normative conflicts such as O A ∧ O ∼A, O A ∧ P ∼A or even O A ∧ ∼O A. On the other hand, DP r still verifies all intuitively reliable inferences valid in Standard Deontic Logic (SDL). DP r interprets a given premise set ‘as normally as possible’ with respect to SDL. Whereas some SDL-rules are ve…Read more
  •  66
    A conditional logic for abduction
    Synthese 191 (15): 3733-3758. 2014.
    We propose a logic of abduction that (i) provides an appropriate formalization of the explanatory conditional, and that (ii) captures the defeasible nature of abductive inference. For (i), we argue that explanatory conditionals are non-classical, and rely on Brian Chellas’s work on conditional logics for providing an alternative formalization of the explanatory conditional. For (ii), we make use of the adaptive logics framework for modeling defeasible reasoning. We show how our proposal allows f…Read more
  •  61
    We present a logic, \, for the discovery of deterministic causal regularities starting from empirical data. Our approach is inspired by Mackie’s theory of causes as INUS-conditions, and implements a more recent adjustment to Mackie’s theory according to which the left-hand side of causal regularities is required to be a minimal disjunction of minimal conjunctions. To derive such regularities from a given set of data, we make use of the adaptive logics framework. Our knowledge of deterministic ca…Read more
  •  37
    Paul Thagard’s theory of deductive coherence, as set out in his Coherence in Thought and Action, faces a regress objection. Thagard’s method of solving deductive coherence problems presupposes some notion of logical consequence. The problem of specifying which logic to use to this end is itself a deductive coherence problem, so we would expect Thagard’s theory to be able to solve it. However, on pain of regress, the theory of deductive coherence cannot reach such a solution
  •  33
    We translate unconstrained and constrained input/output logics as introduced by Makinson and van der Torre to modal logics, using adaptive logics for the constrained case. The resulting reformulation has some additional benefits. First, we obtain a proof-theoretic characterization of input/output logics. Second, we demonstrate that our framework naturally gives rise to useful variants and allows to express important notions that go beyond the expressive means of input/output logics, such as viol…Read more
  •  31
    Inconsistency-Adaptive Dialogical Logic
    Logica Universalis 10 (1): 99-134. 2016.
    Even when inconsistencies are present in our premise set, we can sensibly distinguish between good and bad arguments relying on these premises. In making this distinction, the inconsistency-adaptive approach of Batens strikes a particularly nice balance between inconsistency-tolerance and inferential strength. In this paper, we use the machinery of Batens’ approach to extend the paraconsistent approach to dialogical logic as developed by Rahman and Carnielli. In bringing these frameworks closer …Read more
  •  29
    We present a logic, $$\mathbf {ELI^r}$$ ELI r, for the discovery of deterministic causal regularities starting from empirical data. Our approach is inspired by Mackie’s theory of causes as INUS-conditions, and implements a more recent adjustment to Mackie’s theory according to which the left-hand side of causal regularities is required to be a minimal disjunction of minimal conjunctions. To derive such regularities from a given set of data, we make use of the adaptive logics framework. Our knowl…Read more
  •  25
    A unifying framework for reasoning about normative conflicts
    In Michal Peliš & Vít Punčochář (eds.), The Logica Yearbook, College Publications. pp. 1--14. 2011.
  •  10
    A structured argumentation framework for detaching conditional obligations
    In A. Tamminga O. Roy & M. Willer (eds.), Proceedings of Deon 2016, College Publications. pp. 32--48. 2016.
  •  7
    Structured argumentation with prioritized conditional obligations and permissions
    with Christian Straßer and Jesse Heyninck
    Journal of Logic and Computation 29 (2): 187-214. 2018.
    We present a formal argumentation system for dealing with the detachment of prioritized conditional obligations and permissions. In the presence of facts and constraints, we answer the question whether an unconditional obligation or permission is detachable by considering arguments for and against its detachment. For the evaluation of arguments in favour of detachment, we use a Dung-style argumentation-theoretical semantics. We illustrate how violations and contrary-to-duty scenarios are dealt w…Read more
  •  6
  • A critical assessment of Pollock’s work on logic-based argumentation with suppositions
    with Jesse Heyninck and Christian Straßer
    In Proceedings of Argumentation and Philosophy, . 2018.
  • Argument strength in formal argumentation
    with Jesse Heyninck, Pere Pardo, and Christian Straßer
    Journal of Applied Logics-Ifcolog Journal of Logics and Their Applications 5 (3): 629--675. 2018.
  • An Andersonian deontic logic with contextualized sanctions
    In International Conference on Deontic Logic in Computer Science, . pp. 151--169. 2012.