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Enriching deontic logic with typicality
Legal reasoning is a method that is applied by legal practitioners to make legal decisions. For a scenario, legal reasoning requires not only the facts of the scenario but also the legal rules to be enforced within it. Formal logic has long been used for reasoning tasks in many domains. Deontic logi...
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| Format: | Thesis |
| Language: | English |
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University of Cape Town
2021
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| _version_ | 1867613231166521344 |
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| access_status_str | Open Access |
| author | Chingoma, Julian |
| author2 | Meyer, Thomas |
| author_browse | Chingoma, Julian Meyer, Thomas |
| author_facet | Meyer, Thomas Chingoma, Julian |
| author_sort | Chingoma, Julian |
| collection | Thesis |
| description | Legal reasoning is a method that is applied by legal practitioners to make legal decisions. For a scenario, legal reasoning requires not only the facts of the scenario but also the legal rules to be enforced within it. Formal logic has long been used for reasoning tasks in many domains. Deontic logic is a logic which is often used to formalise legal scenarios with its built-in notions of obligation, permission and prohibition. Within the legal domain, it is important to recognise that there are many exceptions and conflicting obligations. This motivates the enrichment of deontic logic with not only the notion of defeasibility, which allows for reasoning about exceptions, but a stronger notion of typicality which is based on defeasibility. KLM-style defeasible reasoning introduced by Kraus, Lehmann and Magidor (KLM), is a logic system that employs defeasibility while a logic that serves the same role for the stronger notion of typicality is Propositional Typicality Logic (PTL). Deontic paradoxes are often used to examine deontic logic systems as the scenarios arising from the paradoxes' structures produce undesirable results when desirable deontic properties are applied to the scenarios. This is despite the various scenarios themselves seeming intuitive. This dissertation shows that KLM-style defeasible reasoning and PTL are both effective when applied to the analysis of the deontic paradoxes. We first present the background information which comprises propositional logic, which forms the foundation for the other logic systems, as well as the background of KLM-style defeasible reasoning, deontic logic and PTL. We outline the paradoxes along with their issues within the presentation of deontic logic. We then show that for each of the two logic systems we can intuitively translate the paradoxes, satisfy many of the desirable deontic properties and produce reasonable solutions to the issues resulting from the paradoxes. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/32530 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:51.499Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | University of Cape Town |
| publisherStr | University of Cape Town |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/32530 Enriching deontic logic with typicality Chingoma, Julian Meyer, Thomas Deontic Logic Computational Logic Legal reasoning is a method that is applied by legal practitioners to make legal decisions. For a scenario, legal reasoning requires not only the facts of the scenario but also the legal rules to be enforced within it. Formal logic has long been used for reasoning tasks in many domains. Deontic logic is a logic which is often used to formalise legal scenarios with its built-in notions of obligation, permission and prohibition. Within the legal domain, it is important to recognise that there are many exceptions and conflicting obligations. This motivates the enrichment of deontic logic with not only the notion of defeasibility, which allows for reasoning about exceptions, but a stronger notion of typicality which is based on defeasibility. KLM-style defeasible reasoning introduced by Kraus, Lehmann and Magidor (KLM), is a logic system that employs defeasibility while a logic that serves the same role for the stronger notion of typicality is Propositional Typicality Logic (PTL). Deontic paradoxes are often used to examine deontic logic systems as the scenarios arising from the paradoxes' structures produce undesirable results when desirable deontic properties are applied to the scenarios. This is despite the various scenarios themselves seeming intuitive. This dissertation shows that KLM-style defeasible reasoning and PTL are both effective when applied to the analysis of the deontic paradoxes. We first present the background information which comprises propositional logic, which forms the foundation for the other logic systems, as well as the background of KLM-style defeasible reasoning, deontic logic and PTL. We outline the paradoxes along with their issues within the presentation of deontic logic. We then show that for each of the two logic systems we can intuitively translate the paradoxes, satisfy many of the desirable deontic properties and produce reasonable solutions to the issues resulting from the paradoxes. 2021-01-15T09:53:11Z 2021-01-15T09:53:11Z 2020 Master Thesis Masters MSc http://hdl.handle.net/11427/32530 eng application/pdf University of Cape Town Department of Computer Science Faculty of Science |
| spellingShingle | Deontic Logic Computational Logic Chingoma, Julian Enriching deontic logic with typicality |
| thesis_degree_str | Master's |
| title | Enriching deontic logic with typicality |
| title_full | Enriching deontic logic with typicality |
| title_fullStr | Enriching deontic logic with typicality |
| title_full_unstemmed | Enriching deontic logic with typicality |
| title_short | Enriching deontic logic with typicality |
| title_sort | enriching deontic logic with typicality |
| topic | Deontic Logic Computational Logic |
| url | http://hdl.handle.net/11427/32530 |
| work_keys_str_mv | AT chingomajulian enrichingdeonticlogicwithtypicality |