Sartre had long been fascinated with the French novelist GustaveFlaubert. In what some would consider the culmination of his thought,he weds Existentialist biography with Marxian social critique in aHegelian “totalization” of an individual and his era, toproduce the last of his many incompleted projects, a multi-volumestudy of Flaubert's life and times, The Family Idiot(1971–1972). In this work, Sartre joins his Existentialistvocabulary of the 1940s and early 1950s with his Marxian lexicon ofthe late 1950s and 1960s to ask what we can know about a man in thepresent state of our knowledge. This study, which he describes as“a novel that is true,” incarnates that mixture ofphenomenological description, psychological insight, and socialcritique that has become the hallmark of Sartrean philosophy. Thesefeatures doubtless contributed to his being awarded the Nobel prizefor literature, which he characteristically refused along with itssubstantial cash grant lest his acceptance be read as approval of thebourgeois values that the honor seemed to emblemize.
In his essay Existentialism is a Humanism, Jean-Paul Sartre defines what existentialism is by responding to what others have mistakenly accused this philosophy of being. Sartre begins by identifying that the key starting point for existentialism is that human existence precedes human essence (p. 314). There is no a priori human nature formulated by God. After we reject the idea that God exists, Sartre follows Heideggerian thinking by stating that there can only be one being for whom existence precedes essence. This “human reality” (Heidegger’s terminology p.315) arrives first, then defines himself. There is no human identity because there is no God to create an identity for man (p.315). As Sartre says, “he is nothing” (p.315) and it is the existentialist who makes something out of him.
Sartre describes existentialism as being about human existence, as opposed to the existence of other beings. To be sure, it must take other beings into account, but human existence is its focus. The main point is that the existence of a human being is prior to its essence. The basic point here is that a human being makes himself what he is through his free choices, rather than being what he is (having an essence) prior to his existence. There is nothing "objective" about what a human being is: everything starts from the "inside," from the side of the subject. Thus Sartre proclaims that "subjectivity must be the starting point." These themes will be developed in more detail in what follows."
Sartre based his existentialism on human free will. As individuals are free, from the moment of conception, they define their essence throughout their existence. A person's nature is what he or she has done in the past and what that person is doing at the moment. No one is complete until death, when self-definition ceases. Then, how others interpret the individual is based upon the individual's accomplishments and failings.