Understanding Informative Clues: Language Change and Belief Revision

This paper addresses the issue of humans as creatures capable of knowledge from a cognitive perspective. In particular, thanks to the belief revision framewrok, it is possible to provide a better understanding of the cognitive psychology experiments aimed at disproving the capability of apes to display high-level linguistic skills. Further research shows how these experiments have been biased by a misunderstanding of the cognitive relevance of animal intentionality: since intentional relevance is acknowledged as the key for the understanding of actions as meaningful (on behalf of the individual), it is highlighted how the attribution of meaning cannot but rely on contextually-drive clues. If there is a difference between humans and apes, then, it does not rely on the mere possession of different contexts -- otherwise there would be neither ground for comparison, nor possibility of mutual behaviour predictions. Hence, difference relies on the qualitative distinction between biologically-fixed contexts and socially-variable contexts: both of them allow for meaningful and purposeful prediction of others' actions, although the former (apes') strategy relies on systematic inference performed on fixed sets of clues, whereas in the latter (humans') strategy relies on the systematic change of systems of inference, thus varying the set of clues one or more individuals can deal with. Ultimately, this supports the idea of humans as beings that are (at least) capable of systematic and strategic belief revision, which leads to scientific knowledge.