Practical Reasoning in Oscar
John L. Pollock · Philosophical Perspectives · 1995
this paper. These are questions that must be answered before OSCAR can become a full-fledged rational agent. On the conception of rationality embodied in OSCAR (discussed further in my [1993] and [1995]), a rational agent can be regarded as having four basic constituents: . One or more mechanisms for proposing goals. . A mechanism for evaluating the "goodness" of plans. . A mechanism for searching for and adopting plans on the basis of their comparative evaluations by the plan evaluator. . A mechanism for initiating action on the basis of adopted plans (together, possibly, with built-in or learned plan-schemas). These mechanisms constitute a system of practical cognition. On any theory of rationality, plan evaluation and adoption will be based in part on what beliefs the agent has about its situation. Accordingly, an important part of a rational agent is a system of epistemic cognition producing such beliefs. As will be seen below, in OSCAR, the bulk of the work involved in finding, evaluating, and choosing plans and directing action is done by epistemic cognition rather than by dedicated special-purpose modules devoted to practical cognition. The OSCAR architecture begins with a situation-evaluator, which produces a (real-measurable) degree of liking for the agent's current situation. This is presumed to be sensitive to the agent's beliefs about its situation. The likeability of a situation is the degree the agent would like it if it had true beliefs about all relevant aspects of the situation. The objective of the agent's reasoning is to put itself in situations that are more likeable than the situations in which it would find itself if it did not take action. Ideally, plans are evaluated in terms of the expected likeability of their being adopted. This is just the ma...