The classical unities are three principles which, according to certain Italian and French literary critics of the sixteenth and seventeenth centuries, should govern the construction of any drama. The principles are,
- first, that a play should have a single plot-line (unity of action) - no sub-plots are allowed in such dramas;
- secondly, that the events which make up the plot should be confined to a single location (unity of place) - only one scene is to be set; and,
- thirdly, that these events should not extend over a period longer than a single day (unity of time).
The classical unities are sometimes referred to as the Aristotelian unities or simply the three unities.
- Although the doctrine of the classical unities greatly influenced the French dramatists Moliêre (Jean Baptiste Poquelin) (1622-1673) and Jean Racine (1639-1699), it exercised little influence on English playwrights, and is widely regarded as much too restrictive - a criticism which applies with particular force to the second and third principles. Many Greek tragedies and all the plays of Shakespeare violate one or more of the three unities.
- The sixteenth and seventeenth century proponents of the classical unities claimed the authority of the Greek philosopher Aristotle (384-322 BCE) for their three principles, but in fact the discussion of tragic drama in Aristotle's 'Poetics' provides them with only very limited support. Aristotle says nothing about unity of place, and although he does say that, by contrast with epic poetry, which has no limits with regard to time, tragedy tries as far as possible not to exceed, or to exceed only by a little, a single revolution of the sun (ch. 5, 1449b12-14), this is clearly far less prescriptive than the principle of the unity of time. Aristotle would seem to have more sympathy with the principle of unity of action. In a discussion which echoes remarks in Plato's Phaedrus (see 264c and 268d) he says that a tragedy should be the imitation of a single action and constitute a complete whole (ch. 8, 1451a16-19, ch. 7, 1450b23-25), and that, as such, it must have a beginning, a middle, and an end, i.e., the plot must begin at an appropriate point, the events which constitute the 'middle' must follow one another naturally, and the plot must end at an appropriate point (ch. 7, 1450b26-34). He also emphasises that the plot should be tightly constructed and contain no extraneous material: anything the presence or absence of which goes unnoticed is no real part of the whole (ch. 8, 1451a30-35). It is debatable how far this discussion supports the principle of unity of action, at least on a strict interpretation of the latter, and in any case, like the earlier remark that the action of a play should, if possible, be confined to the events of a single day, it is concerned only with tragedy, not with drama in general.