Modal Action Logics for Reasoning about Reactive Systems

Meyer, J-.J.Ch. [Promotor]Riet, R.P. [Promotor]van de Wieringa, R. [Promotor

Action negation and alternative reductions for dynamic deontic logics

AbstractDynamic deontic logics reduce normative assertions about explicit complex actions to standard dynamic logic assertions about the relation between complex actions and violation conditions. We address two general, but related problems in this field. The first is to find a formalization of the notion of ‘action negation’ that (1) has an intuitive interpretation as an action forming combinator and (2) does not impose restrictions on the use of other relevant action combinators such as sequence and iteration, and (3) has a meaningful interpretation in the normative context. The second problem we address concerns the reduction from deontic assertions to dynamic logic assertions. Our first point is that we want this reduction to obey the free-choice semantics for norms. For ought-to-be deontic logics it is generally accepted that the free-choice semantics is counter-intuitive. But for dynamic deontic logics we actually consider it a viable, if not, the better alternative. Our second concern with the reduction is that we want it to be more liberal than the ones that were proposed before in the literature. For instance, Meyer's reduction does not leave room for action whose normative status is neither permitted nor forbidden. We test the logics we define in this paper against a set of minimal logic requirements

Action, Failure and Free Will Choice in Stit Logic

The central axiom of stit theory is independence of agency. This axiom states that simultaneous choices of different agents are independent in the sense that a choice of one agent cannot impair the choice making capacity of other agents. The axiom of independence can then be said to express freedom of choice.1 But freedom of choice is different from freedom of will or freedom of action. In this paper we will suggest how to formally study the differences between freedom of choice, freedom of will and freedom of action. To do so, we will extend stit theory with agent specific epistemic operators thereby introducing the subjective viewpoint into logics for agency. We argue that only by introducing this subjective viewpoint we can formalize free will choice and the distinctions between choosing, acting and failing

BOID*: Autonomous Goal Deliberation through Abduction

The original BOID [5] is a cognitive architecture that unifies Belief, Obligation, Intention and Desire rules to calculate which actions should an agent undertake next. In the current paper, we adapt the original BOID with an aim to model autonomous agency. The new BOID* architecture is able to capture anticipation that we believe to be one of the hallmarks of autonomous agency. We focus on developing algorithms for anticipatory reasoning through a new BOID* goal deliberation component. The key method that BOID* introduces is abductive reasoning as a way to represent motivational attitudes, such as desires and obligations. As a result of deliberation via abduction, BOID* specifies intention revision procedures that connect motivational and informational attitudes. The BOID* is a part of the project to build autonomous AI models that make explicit the reasoning behind adopting future goals, prioritizing selected goals and forming intentions

On Elitist Lifting and Consistency in Structured Argumentation

We address the question of how to lift an ordering over rules to an ordering over arguments (sets of rules) that is well-behaved. It has been shown that so-called elitist lifting may lead to inconsistencies. We give restrictions on the underlying rule-ordering that avoid inconsistency. Then we show that a recently proposed solution – so-called disjoint strict lifting – that was introduced to address conceptual objections, also leads to inconsistency. We show that another recent proposal, telling us to reorder rule-orderings to take argument structure into account before lifting, is able to avoid conceptual problems without leading to any new inconsistencies. We generalise this approach by defining what we call structural rule-orderings and show a correspondence between weakest link and last link lifting of such orderings, which has interesting consequences for the question of consistency. We arrive at our results using a signature-based approach to structured argumentation. Instead of settling on a given framework, such as ASPIC+, we define an argumentation language that allows us to express only those properties of argumentation systems we need to establish our results. This abstract approach simplifies and clarifies the technical work while making our contribution more general

Arguments, responsibilities and moral dilemmas in abductive default logic

We assume that an agent is not responsible for rule-induced extensions of its theory about the world; responsibility requires the presence of a choice. This supports the attractive conclusion that responsibility for rule-based agents can only arise when the agent faces a “dilemma” regarding how to apply the rules. Default logic offers precise formulations of this intuition. However, it turns out that existing definitions force us to recognise too many dilemmas when reasoning about rules. Specifically, not all moral conflicts are moral dilemmas; the crucial element of choice is sometimes missing. To address this, we first present a refined definition for normal default theories, before going on to present a generalisation that applies to abstract argumentation frameworks

Conflicting intentions: rectifying the consistency requirements

Many philosophers are convinced that rationality dictates that one’s overall set of intentions be consistent. The starting point and inspiration for our study is Bratman’s planning theory of intentions. According to this theory, one needs to appeal to the fulfilment of characteristic planning roles to justify norms that apply to our intentions. Our main objective is to demonstrate that one can be rational despite having mutually inconsistent intentions. Conversely, it is also shown that one can be irrational despite having a consistent overall set of intentions. To overcome this paradox, we argue that it is essential for a successful planning system that one’s intentions are practically consistent rather than being consistent or applying an aggregation procedure. Our arguments suggest that a new type of norm is needed: whereas the consistency requirement focuses on rendering the contents of one’s intentions consistent, our new practical consistency requirement demands that one’s intentions be able to simultaneously and unconditionally guide one’s action. We observe that for intentions that conform to the ‘own-action condition’, the practical consistency requirement is equivalent to the traditional consistency requirement. This implies that the consistency requirement only needs to be amended in scenarios of choice under uncertainty