Foundations of Action Theories

Abstract

Before we discuss the purpose of action theories, let us try to provide a suitable and compact definition of the subject in question:

An action theory consists of a formal language that allows adequate specifications of action domains and scenarios, and it tells us precisely what conclusions can be drawn from these specifications.

Of course this informal definition cannot be appreciated without further clarification of the crucial terms used therein. To begin with, by “action domain” we mean any aspect of the world worth formalizing in which the execution of actions plays a central role. This is the case, for instance, if one wants to model an agent that interacts with its environment, i.e., the part of the world it is able to affect. Most importantly, an autonomous agent needs precise knowledge as to the effects of its actions in order to act purpose-oriented and so to achieve pre-determined goals. The latter requires to draw the right conclusions from this knowledge in view of particular situations, in which the agent has acquired partial knowledge about the current state of the environment and has a certain goal in mind.