The notion of an aesthetic norm plays a central role in an aesthetic theory of Jan Mukařovský. In his writings he often describes an aesthetic norm as an extreme case of a rule, but on the other hand he does not seem to consider aesthetic norms to be something altogether different from other kinds of norms.
All norms according to Mukařovský change continuously along with their applications. In this cotribution I propose to inspect Mukařovský's theory of aesthetic norm from a point of view of the analytic philosophy of language, namely with help of two famous discussions stemming form Wittgenstein's Philosophical Investigations, the question of following a rule and that of aspect-seeing.