The paper examines the various usages of the Attic particle μήν and proposes a unified analysis of its main function. I argue that the prevalent analysis of Wakker (1997) needs some important reconsideration when instances of μήν in Platonic dialogue are concerned. First, the particle can target not only the propositional content of a discourse act, but also its illocution (felicity conditions). Second, I propose ‘countering expectations or assumptions of the addressee’ as the basic value of the particle. Functions in terms of commitment are better seen as secondary side effects. Third, I argue that differences in the origin of the countered assumptions or expectations are a natural basis for distinguishing between attitudinal μήν (extra-linguistic context and/or previous words of the addressee) and discourse connective μήν (previous words of the same speaker). It follows from my analysis that strict categorical boundaries between these usages are not to be expected.