Abstract
Machine ethics aims to produce moral behaviour in artificial intelligence (AI) systems,
by equipping such systems with moral reasoning capacities. One approach within
machine ethics is to use deontic logics, i.e. logics that model moral reasoning. Horty
has proposed a particular branch of default logic as a potential basis for deontic logic.
Default logic models many intuitively desirable features of moral reasoning, such as
the possibility of moral conflicts, the idea that moral rules can be overridden, and
the distinction between different types of moral reasons. However, when considered
in the context of AI ethics, Horty’s approach has some shortcomings. Specifically,
the traditional, binary valuation of propositions appears unable to capture realistic
decision-making scenarios, in which moral reasons can have a variety of strengths.
Therefore, this paper explores a numeric default reasoning system, which extends
Horty’s default logic with numeric valuations for propositions and default rules. It is
shown that this new system preserves several advantages of Horty’s logic, but can also
uniquely model certain intuitively common patterns of moral reasoning, specifically
aggregation of reasons. Further directions are suggested, including exploiting the
neurosymbolic character of the reasoning system to facilitate moral learning.
by equipping such systems with moral reasoning capacities. One approach within
machine ethics is to use deontic logics, i.e. logics that model moral reasoning. Horty
has proposed a particular branch of default logic as a potential basis for deontic logic.
Default logic models many intuitively desirable features of moral reasoning, such as
the possibility of moral conflicts, the idea that moral rules can be overridden, and
the distinction between different types of moral reasons. However, when considered
in the context of AI ethics, Horty’s approach has some shortcomings. Specifically,
the traditional, binary valuation of propositions appears unable to capture realistic
decision-making scenarios, in which moral reasons can have a variety of strengths.
Therefore, this paper explores a numeric default reasoning system, which extends
Horty’s default logic with numeric valuations for propositions and default rules. It is
shown that this new system preserves several advantages of Horty’s logic, but can also
uniquely model certain intuitively common patterns of moral reasoning, specifically
aggregation of reasons. Further directions are suggested, including exploiting the
neurosymbolic character of the reasoning system to facilitate moral learning.
| Original language | English |
|---|---|
| Title of host publication | Deontic Logic and Normative Systems |
| Subtitle of host publication | 16th International Conference, DEON 2023 |
| Publisher | College Publications |
| Pages | 235-256 |
| Publication status | Published - 5 Jul 2023 |