Roy C. Flickinger, The Greek theater and its drama (1918)
“ The unity of action is the only one that is universal, since it alone springs from the inmost nature of the drama. Yet even here local conditions make themselves felt. The modern playwright, free (if he pleases and has a producer complaisant enough) to change the scene ten times within a single act and with superior facilities for motivating entrances and exits, delights in shifting different sets of characters back and forth and thus secures an alternation of light and shade, an intermingling of comedy and tragedy quite beyond the ancient dramatist’s reach. ”
