Steven Ungar compares Nausea with French novels of different periods, such as Madame de La Fayette's La Princesse de Clèves (1678), Honoré de Balzac's Le Père Goriot (1835), André Malraux's La Condition humaine (1933), and Annie Ernaux's Une femme (1988), all of which have scenes with men and women faced with choices and "provide literary expressions to concerns with personal identity that vary over time more in detail than in essence."
A main theme in La Nausée is that life is meaningless unless a person makes personal commitments that give it meaning. William Barrett emphasizes that the despair and disgust in Nausea contrast with the total despair of Céline (who is quoted on the flyleaf of the French edition) that leads to nothing; rather, they are a necessary personal recognition that eventuate in "a release from disgust into heroism."
Barrett adds that, "like Adler's, Sartre's is fundamentally a masculine psychology; it misunderstands and disparages the psychology of woman. The humanity of man consists in the For-itself, the masculine component by which we choose, make projects, and generally commit ourselves to a life of action. The element of masculine protest, to use Adler's term, is strong throughout Sartre's writings . . . the disgust . . . of Roquentin, in Nausea, at the bloated roots of the chestnut tree . . ."
Mattey elaborates further on the positive, redeeming aspect of the seemingly bleak, frustrating themes of existentialism that are so apparent in Nausea: "Sartre considered the subjectivity of the starting-point for what a human is as a key thesis of existentialism. The starting-point is subjective because humans make themselves what they are. Most philosophers consider subjectivity to be a bad thing, particularly when it comes to the motivation for action. . . . Sartre responds by claiming that subjectivity is a dignity of human being, not something that degrades us." Therefore, the characteristic anguish and forlornness of existentialism are temporary: only a prerequisite to recognizing individual responsibility and freedom. The basis of ethics is not rule-following. A specific action may be either wrong or right and no specific rule is necessarily valid. What makes the action, either way, ethical is "authenticity," the willingness of the individual to accept responsibility rather than dependence on rules, and to commit to his action. Despair, the existentialist says, is the product of uncertainty: being oriented exclusively to the outcome of a decision rather than to the process yields uncertainty, as we cannot decide the future, only our action.
In his "Introduction" to the American edition of Nausea, the poet and critic Hayden Carruth feels that, even outside those modern writers who are explicitly philosophers in the existentialist tradition, a similar vein of thought is implicit but prominent in a main line through Franz Kafka, Miguel de Unamuno, D. H. Lawrence, André Malraux, and William Faulkner. Carruth says:
'Suffering is the origin of consciousness,' Dostoevsky wrote. But suffering is everywhere in the presence of thought and sensitivity. Sartre for his part has written, and with equal simplicity: 'Life begins on the other side of despair.'
Sartre has written, "What is meant . . . by saying that existence precedes essence? It means that, first of all, man exists, turns up, appears on the scene, and only afterwards defines himself. If man, as the existentialist conceives of him, is undefinable, it is only because he is nothing. Only afterwards will he be something, and he will have made what he will be."
If things—and also people—are contingent, if they "just are," then we are free and we create ourselves solely through our decisions and choices.
David Drake mentions that, in Nausea, Sartre gives several kinds of examples of people whose behavior shows bad faith, who are inauthentic: members of the bourgeoisie who believe their social standing or social skills give them a "right" to exist, or others who embrace the banality of life and attempt to flee from freedom by repeating empty gestures, others who live by perpetuating past versions of themselves as they were or who live for the expectations of others, or those who claim to have found meaning in politics, morality, or ideology.
In simply narrative terms, Roquentin's nausea arises from his near-complete detachment from other people, his not needing much interaction with them for daily necessities: "the fact of his alienation from others is important; as his own work ceases to entertain and to occupy him, Roquentin has nothing that could distract him from the business of existing in its simplest forms." As a practical matter, he could solve his problem by getting a job; but, as a device for developing the novel's theme, his aloneness is a way of making him (and the reader) recognize that there is nothing inherent in the objective nature of the world that would give any necessary meaning to whatever actions he chose, and therefore nothing to restrict his freedom. "[H]is perception of the world around him becomes unstable as objects are disengaged from their usual frames of reference," and he is forced to recognize that freedom is inescapable and that therefore creating a meaning for his life is his own responsibility. "Nothing makes us act the way we do, except our own personal choice."
"But," David Clowney writes, "freedom is frightening, and it is easier to run from it into the safety of roles and realities that are defined by society, or even by your own past. To be free is to be thrown into existence with no "human nature" as an essence to define you, and no definition of the reality into which you are thrown, either. To accept this freedom is to live "authentically"; but most of us run from authenticity. In the most ordinary affairs of daily life, we face the challenge of authentic choice, and the temptation of comfortable inauthenticity. All of Roquentin's experiences are related to these themes from Sartre's philosophy."
Genius is what a man invents when he is looking for a way out.—Jean-Paul Sartre