'Opinion' in Troilus and Cressida

Troilus and Cressida is remarkable (among other things) for the intensity with which it dwells on the words 'opinion' and 'truth'.[1] It explores the conditions of knowledge and feeling which are suggested by the character of the relations between the two words, and between them and others. There are other plays by Shakespeare which seem in a measure obsessed by the semantics of a particular word: Othello by 'honest', Hamlet by 'act', Macbeth by 'time', Coriolanus by 'voice'. But Troilus and Cressida, so distinctive in other ways, is unique also in the degree to which its language is saturated by 'opinion' and by the various but interconnected ideas of which it is the centre. I shall try later to justify that word 'saturated'. But first I want to illustrate, of course much too simply and with inadequate documentation, the history and semantic range of the word 'opinion'.