“We must not confuse the present with the past. With regard to the past, no further action is possible.”

Pt. III : The Positive Aspect of Ambiguity http://www.marxists.org/reference/subject/ethics/de-beauvoir/ambiguity/ch03.htm#s2, Ch. 1 : The Aesthetic Attitude
The Ethics of Ambiguity (1947)
Context: We must not confuse the present with the past. With regard to the past, no further action is possible. There have been war, plague, scandal, and treason, and there is no way of our preventing their having taken place; the executioner became an executioner and the victim underwent his fate as a victim without us; all that we can do is to reveal it, to integrate it into the human heritage, to raise it to the dignity of the aesthetic existence which bears within itself its finality; but first this history had to occur: it occurred as scandal, revolt, crime, or sacrifice, and we were able to try to save it only because it first offered us a form. Today must also exist before being confirmed in its existence: its destination in such a way that everything about it already seemed justified and that there was no more of it to reject, then there would also be nothing to say about it, for no form would take shape in it; it is revealed only through rejection, desire, hate and love. In order for the artist to have a world to express he must first be situated in this world, oppressed or oppressing, resigned or rebellious, a man among men. But at the heart of his existence he finds the exigency which is common to all men; he must first will freedom within himself and universally; he must try to conquer it: in the light of this project situations are graded and reasons for acting are made manifest.