Abstract
In his famous 1982 paper, Allen Newell [22, 23] introduced the notion of knowledge level to
indicate a level of analysis, and prediction, of the rational behavior of a cognitive articial agent.
This analysis concerns the investigation about the availability of the agent knowledge, in order
to pursue its own goals, and is based on the so-called Rationality Principle (an assumption
according to which "an agent will use the knowledge it has of its environment to achieve its
goals" [22, p. 17]. By using the Newell's own words: "To treat a system at the knowledge level
is to treat it as having some knowledge, some goals, and believing it will do whatever is within
its power to attain its goals, in so far as its knowledge indicates" [22, p. 13].
In the last decades, the importance of the knowledge level has been historically and system-
atically downsized by the research area in cognitive architectures (CAs), whose interests have
been mainly focused on the analysis and the development of mechanisms and the processes
governing human and (articial) cognition. The knowledge level in CAs, however, represents
a crucial level of analysis for the development of such articial general systems and therefore
deserves greater research attention [17]. In the following, we will discuss areas of broad agree-
ment and outline the main problematic aspects that should be faced within a Common Model
of Cognition [12]. Such aspects, departing from an analysis at the knowledge level, also clearly
impact both lower (e.g. representational) and higher (e.g. social) levels.