(noun) a rhetorical or literary figure in which words, grammatical constructions, or concepts are repeated in reverse order, in the same or a modified form; e.g. ‘Poetry is the record of the best and happiest moments of the happiest and best minds.’.
the two sides of that chiasmus would be in constant tension
I vaguely remember trying to memorise this term for IB English but I guess I forgot ... referring to DFW's attempt to pursue "morally passionate, passionately moral fiction"