Tragedy is consider symmetrical, a clash between two alike forces. That is why in tragedy there is no winner or loser. It does not proclaim a conclusion. It does not condemn, it is inclusive rather exclusive.
There are many definitions for the tragedy, which eventually all of are originated form Aristotle’s:
“Tragedy, then, is an imitation of a noble and complete action, having the proper magnitude; it employs language that has been artistically enhanced,…, it is presented in dramatic, not narrative form, and achieves, through the representation of pitiable and fearful incidents, the catharsis of such incidents” Poetics Pp.3
Aristotle indicates that the medium of tragedy is a drama, not narrative; tragedy shows rather than tells. Thus, tragedy stands higher than the history because the history simply relates what has happened, while tragedy dramatizes the current to what may happened. History thus deals with the particular, and tragedy with the universe (cosmos): it creates a cause-and-effect chain that is progressively will substantiate out of its frame. What happened in the stage will be eventually repeated in any time, at any situation.
Greeks saw this importance of the drama - in difficult times- as the only remedy for residing the satiability. Roman heavily used it as a political tool in order to unite the distressed public.
The facts that tragedy was a simulation of the universe, beyond any define classes; various audiences would digest the similar pain. Aristotle defines the goal of tragedy to simulate the catharsis. The word ‘catharsis’ originally means ‘purging’ and Aristotle seems to consider tragedy as a medical metaphor , using the pity and fear to purge and clean the harmful emotions , leaving the audience better experiences . Later he relates the tragedy to the pleasure, reaching the level of contemplation.
Back to the Michell Serres and definition of the state of plague. Tragedy was the only cure for the society.
When there were no absolute enemies, when there were no certainties. It is practice of reality rather the fictional fantasy. It is representation of current reality. It is morphine for the citizens to relive the pains.