Logical methods for Deontic Explanations (LoDEx)

Deontic reasoning, which involves obligation and related notions, is highly important in a variety of fields—from law and ethics to artificial intelligence. The combination of deontic logic and formal argumentation provides a fruitful theoretical basis for modelling this type of reasoning. The three partners of the “LOgical methods for Deontic EXplanations” (LoDEx) project represent important developments in the area: Ciabattoni (Vienna University of Technology) addresses practical concerns in mathematics and logic, Straßer (Ruhr University Bochum) uses formal methods in philosophy, and van der Torre (University of Luxembourg) provides legal and ethical reasoners in computer science and artificial intelligence. Now they are joining forces to develop a formal theory of what they call deontic explanations.

Deontic explanations provide reasons why some deontic notions hold and others do not. They provide answers to complex questions like “Why should a child be entrusted to its father, rather than its mother, given a specific context?” or “Should someone who follows the faith of Jehova’s Witnesses be forced to undergo a life-saving blood transfusion? Why (not)?”. By targeting the understanding and transparent presentation of reasoning processes, deontic explanations are a major concern in many fields.

Driven by case studies in (bio)ethics and law, LoDEx develops logical methods with tool support to formalise and reason about deontic explanations. By integrating both preference-based and norm-based explanations, LoDEx takes up the challenge raised by Makinson (1998) and Horty (2014) of formulating a unified logical theory combining several disconnected methods from the field of deontic logic. By means of formal argumentation and dialogues, explanations are tailored to ensure explainee comprehension with the generation of fine-tuned explanations relative to the explainee’s preconceptions and expectations.

LoDEx fills a central gap in formal theories of normative reasoning, which so far have been concerned with justifications rather than personalised explanations. There is an urgent demand for deontic explanations in law and (bio)ethics, two domains where deontic reasoning is particularly involved and which are rich in conflicts. To meet this demand, the formal methods of LoDEx will be applied to and evaluated on key case studies from these areas. Computer-supported tools will be developed in order to experiment with the methods, the formal legal and bioethical theories, and applications of those theories. We will use the LogiKEy methodology for this purpose. The dissemination of the newly created LogiKEY data sets will enable reusability and facilitate implementations for the deontic logic community. LoDEx methods, tools and applications will contribute to the timely interdisciplinary challenge of providing formal foundations to more human-centred logic and reasoning.