'Objective correlative' was a phrase coined by T.S. Eliot in a 1919 essay on Hamlet. Essentially, he said that if we are to believe in the emotion characters are showing in a work of art, that emotion must be relatable to, in scale with, the situation and events which surround it--what Eliot called its 'formula'. If the emotion seems too much or too little for these externals, we find it unconvincing. The idea is highly debatable (and Eliot himself came to deplore the way his phrase became standard jargon). In much literature and drama, and particularly in stage comedy, it is precisely the disparity between circumstances and emotional reaction which makes the art--and in other works, for example Medea or Madame Bovary, it is hard to see how the idea of an objective correlative has any relevance at all.
