Being and Nothingness

Throughout Being and Nothingness, Sartre uses the term “appearances.” In philosophy, this refers to what seems to be or what can be perceived. In Sartre’s work, appearances are aligned with phenomenon: They refer to experiences and what is revealed through the senses. Sartre claims that appearances create essences.

Traditionally, the idea of authenticity means being oneself and living in a way that aligns with one’s desires and beliefs. Sartre’s definition differs slightly. Since he sees the world as absurd, he prescribes that living authentically is the only way to break the pattern of its absurdity. This means that humans should construct their own definitions of morality and make choices independent of external forces. In doing so, they live authentically.

The existentialist principle of “bad faith” refers to what happens when humans live inauthentically. Sartre proposes that when humans embrace false ideas about purpose and meaning, they are submitting to external forces rather than utilizing their free will.

René Descartes wrote in his 1637 Discourse on Method, “I think, therefore I am.” This statement summarizes the concept of cogito: Humans exist because of the knowledge of their existence. Sartre vehemently challenges this idea. He argues that knowledge implies reflection that cannot occur at the same time as existence. Instead, Sartre proposes the idea of “preflective cogito,” which is better translated as an awareness of the self rather than knowledge.

This Latin phrase is best translated as “being one’s own cause.” This means that a person’s essence or purpose in life is determined by themselves; they are the reason for their existence.

The term "essence” refers to the core property or set of properties that endow something with its identity; essences make something what it is. The term was used by Ancient Greek philosophers, including Aristotle, to make sense of what distinguishes one thing from another. The idea is rooted in the belief that animals and humans have specific essences that are placed there by a divine power. Sartre repeatedly challenges this idea by arguing that essences are created in a person’s life by their decisions and actions: Existence manifests essences.

Existentialists propose that life is meaningless in the traditional sense, meaning that it does not have an intrinsic purpose set forth by God or any other external force. Instead, existentialists propose that all things can give life meaning, but also nothing can. This means that there are no absolutes by which humans can abide; concepts of fairness, justice, morality, and rules are all false, and adhering to them is absurd. Sartre argues that one of the great challenges of the human condition is living in a senseless world while being granted an abundance of freedom to do as one pleases. He suggests that the only answer is to live authentically—to recognize absurdity and to choose for oneself a moral code.

Idealism is the philosophical assumption that there is a spiritual nature to existence in the world. In Being and Nothingness, Sartre critiques the principles of idealism, which stand in complete contrast to the principles of existentialism—the latter proposes that existence and the world are meaningless and lack a spiritual purpose.

Sartre uses intersubjectivity as a response to solipsism. This philosophical approach argues that the shared perception of reality between two individuals causes them to be aware of one another’s consciousness.

Marxism is a form of leftist socioeconomic theory used to understand class relations and society. Where Marxism focuses on the objective collective, Sartre’s theories emphasize the subjective individual.

Nihilism is the rejection of all moral and philosophical constraints such as truth and knowledge. The theory proposes that life is meaningless and human values are purposeless. Early forms of the word appeared in German publications in the 18th century. Nietzsche popularized the term when he used it to examine Western morality.

In philosophy, noumenal refers to the possession of the qualities of reality rather than a phenomenal existence. Noumenal existence embraces the idea that humans have an inherent purpose; they exist for a reason that is independent of experience and perception.

Ontology refers to the branch of philosophy concerned with the nature of existence, or the nature of being.

In philosophy, phenomenon refers to what can be perceived through the senses. For example, phenomenological research relies upon the experiences of individuals and what they have seen, heard, etc. Sartre claims that one of the problems with philosophy in the past is its adherence to a system of dualities. He proposes to replace those dualities with singular understandings of specific phenomenon.

Solipsism is a philosophical theory that suggests that humans can only gain awareness of their personal self and can never be made fully aware of the consciousness of others. Sartre attempts to override this theory by using intersubjective theories.