In this paper we examine various constraints on the actions of agents in such situations and discuss the effects of these constraints on their derived utility. In particular, we define and analyze basic raiionaliiy; we consider various assumptions about independence; and we demonstrate the advantages of extending the definition of rationality from individual actions to decision procedures.

The first is to have an adequate model of the cognitive state of other agents. The second is to form plans under the constraint of resource limitations: i.e., an agent does not always have an infinite amount of time to sit and think of plans while the world changes under him; he must act. These two problems are obviously interlinked since, to have a realistic model of the cognitive states of other agents, who are presumably similar to himself, an agent must reason about the resource limitations they are subject to in reasoning about the world. In this paper we address both problems with reference to AI planning system robots and one part of their cognitive state, namely beliefs. Our goal is to pursue what might be called robot psychology: to construct a plausible model of robot beliefs by examining robots' internal representations of the world.

We are interested in constructing a computer agent whose behaviour will be intelligent enough to perform cooperative tasks involving other agents like itself. The construction of such agents has been a major goal of artificial intelligence research. One of the key tasks such an agent must perform is to form plans to carry out its intentions in a complex world in which other planning agents also exist. To construct such agents, it will be necessary to address a number of issues that concern the interaction of knowledge, actions, and planning. Briefly stated, an agent at planning time must take into account what his future states of knowledge will be if he is to form plans that he can execute; and if he must incorporate the plans of other agents into his own, then he must also be able to reason about the knowledge and plans of other agents in an appropriate way.

This is the first presidential address of AAAI, the American Association for Artificial Intelligence. In the grand scheme of history of artificial intelligence (AI), this is surely a minor event. The field this scientific society represents has been thriving for quite some time. No doubt the society itself will make solid contributions to the health of our field. But it is too much to expect a presidential address to have a major impact. So what is the role of the presidential address and what is the significance of the first one? I believe its role is to set a tone, to provide an emphasis. I think the role of the first address is to take a stand about what that tone and emphasis should be-set expectations for future addresses and to communicate to my fellow presidents. Only two foci are really possible for a presidential address: the state of the society or the state of the science. I believe the latter to be correct focus. AAAI itself, its nature and its relationship to the larger society that surrounds it, are surely important. However, our main business is to help AI become a science -- albeit a science with a strong engineering flavor. Thus, though a president's address cannot be narrow or highly technical, it can certainly address a substantive issue. That is what I propose to do.