Designing Normative Theories for Ethical and Legal Reasoning: LogiKEy Framework, Methodology, and Tool Support

A framework and methodology---termed LogiKEy---for the design and engineering of ethical reasoners, normative theories and deontic logics is presented. The overall motivation is the development of suitable means for the control and governance of intelligent autonomous systems. LogiKEy's unifying formal framework is based on semantical embeddings of deontic logics, logic combinations and ethico-legal domain theories in expressive classic higher-order logic (HOL). This meta-logical approach enables the provision of powerful tool support in LogiKEy: off-the-shelf theorem provers and model finders for HOL are assisting the LogiKEy designer of ethical intelligent agents to flexibly experiment with underlying logics and their combinations, with ethico-legal domain theories, and with concrete examples---all at the same time. Continuous improvements of these off-the-shelf provers, without further ado, leverage the reasoning performance in LogiKEy. Case studies, in which the LogiKEy framework and methodology has been applied and tested, give evidence that HOL's undecidability often does not hinder efficient experimentation.Comment: 50 pages; 10 figure

Free choice permission in defeasible deontic logic

Free Choice Permission is one of the challenges for the formalisation of norms. In this paper, we follow a novel approach that accepts Free Choice Permission in a restricted form. The intuition behind the guarded form is strongly aligned with the idea of defeasibility. Accordingly, we investigate how to model the guarded form in Defeasible Deontic Logic extended with disjunctive permissions

New Work For Certainty

This paper argues that we should assign certainty a central place in epistemology. While epistemic certainty played an important role in the history of epistemology, recent epistemology has tended to dismiss certainty as an unattainable ideal, focusing its attention on knowledge instead. I argue that this is a mistake. Attending to certainty attributions in the wild suggests that much of our everyday knowledge qualifies, in appropriate contexts, as certain. After developing a semantics for certainty ascriptions, I put certainty to explanatory work. Specifically, I argue that by taking certainty as our central epistemic notion, we can shed light on a variety of important topics, including evidence and evidential probability, epistemic modals, and the normative constraints on credence and assertion

A Deontic Logic Reasoning Infrastructure

A flexible infrastructure for the automation of deontic and normative reasoning is presented. Our motivation is the development, study and provision of legal and moral reasoning competencies in future intelligent machines. Since there is no consensus on the “best” deontic logic formalisms and since the answer may be application specific, a flexible infrastructure is proposed in which candidate logic formalisms can be varied, assessed and compared in experimental ethics application studies. Our work thus links the historically rich research areas of classical higher-order logic, deontic logics, normative reasoning and formal ethics

Philosophical logics - a survey and a bibliography

Intensional logics attract the attention of researchers from differing academic backgrounds and various scientific interests. My aim is to sketch the philosophical background of alethic, doxastic, and deontic logics, their formal and metaphysical presumptions and their various problems and paradoxes, without attempting formal rigor. A bibliography, concise on philosophical writings, is meant to allow the reader\u27s access to the maze of literature in the field

The deontic quadecagon.

There are a number of concepts of common-sense morality, what one must do, what one ought to do, the supererogatory, the minimum that duty allows, the morally optional and the morally indifferent, that philosophers have been hard-pressed to represent in an integrated conceptual framework. Indeed, many philosophers have despaired at the attempt and concluded that only a fragment of these concepts belong to that fundamental sphere of morality that is the central focus of the ethicist. For example, the traditional scheme, with its triad of the obligatory, the forbidden and the permissible, pigeonholes all actions into three mutually exclusive and exhaustive classes: those which are obligatory, those which are forbidden and those which are optional. Hence, at best, it can represent exactly two of the six aforementioned concepts. For from the standpoint of this scheme, what one must do and what one ought to do can\u27t be distinguished and hence they can\u27t both be represented. Although the morally optional can be represented, the supererogatory, one of its subclasses, cannot be represented. Furthermore, the morally indifferent, another subclass of the optional--one which is obviously disjoint from the supererogatory--cannot be represented. Finally, the minimum that duty allows finds no distinctive place in the traditional scheme. Thus, on the face of it, the traditional scheme is radically incomplete. I present, motivate and defend a new conceptual scheme for common-sense morality in which these concepts (and others) are represented and systematically integrated. An intuitively motivated semantic framework underpinning this conceptual scheme is also presented. Such a scheme, along with the associated semantic framework, is motivated by reflecting on the supererogationist\u27s objections to utilitarianism and to the traditional scheme. But in addition, a new integrated network of linguistic motivations for this conceptual scheme is uncovered, one which is completely independent of supererogationistic considerations. Hence, these two separate sources of evidence for the centrality of this new scheme to our pre-theoretic thinking corroborate one another--thus jointly boosting the evidence beyond the mere sum of their separate evidential values

Generics, modality, and morality

The issues in this dissertation reside at the intersections of, and relationships between, topics concerning the meaning of generic generalizations, natural language modality, the nature and role of moral principles, and the place of supererogation in the overall structure of the normative domain. In ’Generics and Weak Necessity’, I argue that generics—exception-granting generalizations such as ’Birds fly’ and ’Tigers are striped’—involve a covert weak necessity modal at logical form. I argue that this improves our understanding of the variability and diversity of generics. This chapter also argues that we can account for variability concerning normative generics within a modal approach to generics. In ’The Genericity of Moral Principles’, I provide evidence for the view that moral principles are generic generalizations, and, on the basis of this claim, argue that moral principles do not provide adequate support for reasoning about the moral statuses of particular cases. In ’Supererogation and the Structure of the Normative Domain’, I investigate the diversity of the central normative modal notions and argue that we should distinguish between two senses of supererogation based different ways deontic modals are sensitive to background information

Multiagent Deontic Logic and its Challenges from a Normative Systems Perspective

This article gives an overview of several challenges studied in deontic logic, with an emphasis on challenges involving agents. We start with traditional modal deontic logic using preferences to address the challenge of contrary-toduty reasoning, and STIT theory addressing the challenges of non-deterministic actions, moral luck and procrastination. Then we turn to alternative normbased deontic logics detaching obligations from norms to address the challenge of Jørgensen’s dilemma, including the question how to derive obligations from a normative system when agents cannot assume that other agents comply with their norms. We discuss also some traditional challenges from the viewpoint of normative systems: when a set of norms may be termed ‘coherent’, how to deal with normative conflicts, how to combine normative systems and traditional deontic logic, how various kinds of permission can be accommodated, how meaning postulates and counts-as conditionals can be taken into account,how sets of norms may be revised and merged, and how normative systems can be combined with game theory. The normative systems perspective means that norms, not ideality or preference, should take the central position in deontic semantics, and that a semantics that represents norms explicitly provides a helpful tool for analysing, clarifying and solving the problems of deontic logic. We focus on the challenges rather than trying to give full coverage of related work, for which we refer to the handbook of deontic logic and normative systems