L'esprit de l'escalier or (, , ; ) is a French term used in English for the predicament of thinking of the perfect reply too late.
This name for the phenomenon comes from French encyclopedist and philosopher Denis Diderot's description of such a situation in his " ("Paradox of the Actor"). During a dinner at the home of statesman Jacques Necker, a remark was made to Diderot which left him speechless at the time, because, he explains, "a sensitive man, such as myself, overwhelmed by the argument leveled against him, becomes confused and doesn't come to himself again until at the bottom of the stairs" (").
In this case, "the bottom of the stairs" refers to the architecture of the kind of or mansion to which Diderot had been invited. In such houses, the reception rooms were on the , one floor above the ground floor. To have reached the bottom of the stairs means to have definitively left the gathering.
An older English term that was sometimes used for this meaning is afterwit; it is used, for example, in James Joyce's Ulysses (Chapter 9).
The Yiddish and the German loan translation ' express the same idea as . However, in contemporary German has an additional meaning: it refers to events or facts that seem to contradict their own background or context. The frequently used phrase , , derives from the title of a book by that name by (1882; much expanded 1895) and means or .
In Russian, the notion is close to the native Russian saying .
In Chinese, a close equivalent is , referring to remarks or actions that come too late to be useful.
English speakers sometimes call this "escalator wit" or "staircase wit".