| 1. |
- Cantwell, John
(author)
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A Formal Model of Multi-Agent Belief-Interaction
- 2006
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In: Journal of Logic, Language and Information. - : Springer Science and Business Media LLC. - 0925-8531 .- 1572-9583. ; 15:4, s. 303-329
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Journal article (peer-reviewed)abstract
- A semantics is presented for belief revision in the face of common announcements to a group of agents that have beliefs about each other's beliefs. The semantics is based on the idea that possible worlds can be viewed as having an internal-structure, representing the belief independent features of the world, and the respective belief states of the agents in a modular fashion. Modularity guarantees that changing one aspect of the world (a belief independent feature or a belief state) has no effect on any other aspect of the world. This allows us to employ an AGM-style selection function to represent revision. The semantics is given a complete axiomatisation (identical to the axiomatisation found by Gerbrandy and Groeneveld for a semantics based on non-wellfounded set theory) for the special case of expansion.
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| 2. |
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| 3. |
- Cantwell, John
(author)
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Changing the modal context
- 2008
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In: Theoria. - : Wiley. - 0040-5825 .- 1755-2567. ; 74:4, s. 331-351
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Journal article (peer-reviewed)abstract
- Conditionals that contain a modality in the consequent give rise to a particular semantic phenomenon whereby the antecedent of the conditional blocks possibilities when interpreting the modality in the consequent. This explains the puzzling logical behaviour of constructions like "If you don't buy a lottery ticket, you can't win", "If you eat that poison, it is unlikely that you will survive the day" and "If you kill Harry, you ought to kill him gently". In this paper it is argued that a semantic version of the Ramsey Test provides a key in the analysis of such constructions. The logic for this semantics is axiomatized and some examples are studied, among them a well-known puzzle for contrary-to-duty obligations.
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| 4. |
- Cantwell, John
(author)
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Conditionals in reasoning
- 2009
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In: Synthese. - : Springer Science and Business Media LLC. - 0039-7857 .- 1573-0964. ; 171:1, s. 47-75
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Journal article (peer-reviewed)abstract
- The paper presents a non-monotonic inference relation on a language containing a conditional that satisfies the Ramsey Test. The logic is a weakening of classical logic and preserves many of the 'paradoxes of implication' associated with the material implication. It is argued, however, that once one makes the proper distinction between supposing that something is the case and accepting that it is the case, these 'paradoxes' cease to be counterintuitive. A representation theorem is provided where conditionals are given a non-bivalent semantics and epistemic states are represented via preferential models.
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| 5. |
- Cantwell, John
(author)
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Indicative conditionals : Factual or Epistemic
- 2008
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In: Studia Logica. - : Springer Science and Business Media LLC. - 0039-3215 .- 1572-8730. ; 88:1, s. 157-194
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Journal article (peer-reviewed)abstract
- It is argued that indicative conditionals are best viewed as having truthconditions (and so they are in part factual) but that these truth conditions are ‘gappy’which leaves an explanatory gap that can only be filled by epistemic considerations (and soindicative conditionals are in part epistemic). This dual nature of indicative conditionalsgives reason to rethink the relationship between logic viewed as a descriptive discipline(focusing on semantics) and logic viewed as a discipline with a normative import (focusingon epistemic notions such as ‘reasoning’, ‘beliefs’ and ‘assumptions’). In particular, it isargued that the development of formal models for epistemic states can serve as a startingpoint for exploring logic when viewed as a normative discipline.
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| 6. |
- Cantwell, John
(author)
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The laws of non-bivalent probability
- 2006
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In: Logic and Logical Philosophy. - 1425-3305 .- 2300-9802. ; 15, s. 163-171
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Journal article (peer-reviewed)abstract
- Non-bivalent languages (languages containing sentences that canbe true, false or neither) are given a probabilitistic interpretation in termsof betting quotients. Necessary and sufficient conditions for avoiding Dutchbooks—the laws of non-bivalent probability—in such a setting are provided.
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| 7. |
- Cantwell, John
(author)
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The Logic of Conditional Negation
- 2008
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In: Notre Dame Journal of Formal Logic. - : Duke University Press. - 0029-4527 .- 1939-0726. ; 49:3, s. 245-260
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Journal article (peer-reviewed)abstract
- It is argued that the "inner" negation ∼ familiar from 3-valued logic can be interpreted as a form of "conditional" negation: ∼A is read 'A is false if it has a truth value'. It is argued that this reading squares well with a particular 3-valued interpretation of a conditional that in the literature has been seen as a serious candidate for capturing the truth conditions of the natural language indicative conditional (e.g., "If Jim went to the party he had a good time"). It is shown that the logic induced by the semantics shares many familiar properties with classical negation, but is orthogonal to both intuitionistic and classical negation: it differs from both in validating the inference from A→∼B to ∼(A→B).
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| 8. |
- Cantwell, John
(author)
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The logic of dominance reasoning
- 2006
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In: Journal of Philosophical Logic. - : Springer Science and Business Media LLC. - 0022-3611 .- 1573-0433. ; 35:1, s. 41-63
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Journal article (peer-reviewed)abstract
- The logic of dominance arguments is analyzed using two different kinds of conditionals: indicative (epistemic) and subjunctive (counter-factual). It is shown that on the indicative interpretation an assumption of independence is needed for a dominance argument to go through. It is also shown that on the subjunctive interpretation no assumption of independence is needed once the standard premises of the dominance argument are true, but that independence plays an important role in arguing for the truth of the premises of the dominance argument. A key feature of the analysis is the interpretation of the doubly conditional comparative I will get a better outcome if A than if B which is taken to have the structure (the outcome if A) is better than (the outcome if B).
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| 9. |
- Clausen Mork, Jonas, 1975-
(author)
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Is it safe? safety factor reasoning in policy-making under uncertainty
- 2006
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Licentiate thesis (other academic/artistic)abstract
- This thesis examines the practice of using safety factors in decision-making under uncertainty, in particular in the areas of toxicology and civil engineering. The aim is to expose and clarify some of the philosophical issues surrounding the practice. Paper I (co-written with Sven Ove Hansson and Fred Nilsson) gives an historical background to the practice of formal safety factor and safety margin use. The notion of an uncertainty function is presented as a more general concept covering safety margins, safety factors and the related uncertainty factors. Three categories of uncertainty functions are identified: explicit, implicit and natural safety reserves. Finally, the problems of countervailing risks and distribution arbitrariness are discussed. Paper II (co-written with John Cantwell) discusses the relation between decision-making with safety factor rules and the ideal of formal normative decision theory. The role of safety factor rules in practical and theoretical reasoning is also examined and certain difficulties regarding normative evaluation of safety factor rules are pointed out. Paper III (co-written with Sven Ove Hansson) looks at two current regulatory systems under development: Eurocodes for construction and REACH for chemicals. The two regulations have many similarities but reactions to them have been highly divergent. The differences are discussed and some hypotheses as to their explanation are suggested.
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| 10. |
- Clausen Mork, Jonas, et al.
(author)
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Reasoning with Safety Factor Rules
- 2007
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In: Techné. - 1091-8264 .- 2691-5928. ; 11:1, s. 55-70
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Journal article (peer-reviewed)abstract
- Safety factor rules are used for drawing putatively reasonable conclusions from incomplete datasets. The paper attempts to provide answers to four questions: “How are safety factors used?”, “When are safety factors used?”, “Why are safety used?” and “How do safety factor rules relate to decision theory?”. The authors conclude that safety factor rules should be regarded as decision methods rather than as criteria of rightness and that they can be used in both practical and theoretical reasoning. Simplicity of application and inability or unwillingness to defer judgment appear to be important factors in explaining why the rules are used.
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