T.S. Eliot: The Objective Correlative

A now famous term used by T.S. Eliot in an essay On Hamlet (1919). The relevant passage is "the only way to express an emotion in the form of art is by finding an objective correlative; in other words, a set of objects, a situation, a chain of events which shall be the formula of that particular emotion; such as when the external facts which must terminate in sensory experience, are given, the emotion is immediately evoked".
In the essay Mr Eliot explains how a person can reach a work of art. He writes that it is necessary to take a work of art and compare it with the works of tradition, as himself does. The correlative objective comes from two words: "correlative" means something that makes a connection between other things, while "objective" means it is referred to an object.
Mr Eliot wonders what is the better way to comunicate feelings and emotions. He considers two important works of art that dealt with emotions: Shakespeare's Hamlet and Macbeth, "the great tragedies" (because they are timeless). He compares them and he writes that when Shakespeare created the characters, he characterized them with exact functions. Shakespeare established that Lady Macbeth, who is anymore able to control her emotions, becomes sleepwalker: her consciousness is not able to contain emotions, that inevitably emerge. Analysing it, Mr Eliot realizes that Shakespeare in this way found the right correlative objective to express that emotion.
When T.S. Eliot analyses Hamlet, he writes that the main character develops a tragedy in order to make revival to his mother and uncle what was happened to his father. Hamlet is not really mad, but Mr Eliot writes that the way Shakespeare used to comunicate Hamlet's emotion is not effective as in Macbeth, because there he found the exact correlative objective (he found the linguistic object that has been linking Lady Macbeth's consciousness to public's one).
So, what did Shakespeare mistake? In Macbeth Shakespeare found the right formula, while in Hamlet he did not because Hamlet is controlled by madness, that is inexpressible, so Shakespeare used too many words to express it. So public losts itself in the excess of words and there is not syntony between the character and the public.
So Mr Eliot realizes that there must be a bilance in order to express emotions, because contents are the form. Thoughts, emotions and actions are all united. If there were no balance, there would be a detachment between what is communicated and who receives it. So the correlative objective units the language that communicates emotions and the emotions themselves.