For Sartre, human existence is conscious being, “being-for-itself” (pour-soi). Human existence as “being-for-itself” is temporal—always in some present, always on the way from some past toward some future. Another characteristic of human existence is its dependence on things. Things have a fundamentally different mode of existence: “being-in-itself” (en-soi). They have no consciousness, no possibilities, no freedom. Their being is complete as it is.
One danger for human existence is that it may be falsely reduced from free “being-for-itself” to unfree “being-in-itself.” This threat may come from others or from oneself. One may intentionally avoid freedom and the anxiety of conscious decision making by convincing oneself that one has no options, but this is to reduce oneself to an object, to use freedom to deny freedom, to live in “bad faith” (mauvaise foi).
The existence of “the others” (autrui) is a fundamental fact of human existence. In Sartre’s view, however, the constant factor in interpersonal relationships is not potential harmony, but inevitable alienation. Lovers, in his analysis, cannot avoid the objectifying will to possess, which denies freedom and reduces the loved one from “being-for-itself” to “being-in-itself.”