A formal account of nondeterministic and failed actions
James P. Delgrande, Hector J. Levesque · 2013
Nondeterminism is pervasive in all but the simplest action domains: an agent may flip a coin or pick up a different object than intended, or an action may fail and may fail in different ways. In this paper we provide a qualitative theory of nondeter-minism. The account is based on an epistemic ex-tension to the situation calculus that accommodates sensing actions. Our position is that nondetermin-ism is an epistemic phenomenon, and that the world is most usefully regarded as deterministic. Nonde-terminism arises from an agent’s limited awareness and perception. The account offers several advan-tages: an agent has a set of categorical (as opposed to probabilistic) beliefs, yet can deal with equally-likely outcomes (such as in flipping a fair coin) or with outcomes of differing plausibility (such as an action that may on rare occasion fail). 1