Existentialism is a philosophical movement which focuses on topics such as human freedom and the search for meaning in an indifferent universe. Jean-Paul Sartre, one of its central figures in his 1945 lecture Existentialism is a Humanism, advocates a worldview in which human existence (our choices and our actions) are central to how a human is defined, rather than some predefined human nature. Sartre’s existentialism led to an idea of freedom in which we decide how we are defined and take responsibility for our actions. This essay will explore the rationales for, and implications of Sartre’s existentialist theory that “existence precedes essence” and how it relates to the way in which we should live.
To understand what Sartre means by “existence precedes essence”, an understanding of how “existence” and “essence”, and the various ways in which they are defined is required. In Existentialism as a Humanism, Sartre assumed the existence of humans to be a self-evident, conscious reality, without rigorous proof, stating that “man first of all exists [and] encounters himself”. Essence, on the other hand, is classically defined as a set of conditional qualifiers that an object or concept must possess to be considered that concept or object. Consider the following. Let us define the essence of water as: “a molecule”, “one oxygen atom” and “two hydrogen atoms”. From this prescriptive definition, we can infer that non-molecular objects, or a molecule with an incorrect number of oxygen or hydrogen atoms is essentially not “water”. By contraposition, we can infer that if an object is essentially “water”, then this object must satisfy the molecular properties as previously stated. To put simply, an essence of an object or concept are sufficient conditions for its existence. Under this definition, essence precedes existence since objects or concepts are contingent, being instantiated by the satisfaction of their essential elements (conditional qualifiers). In general, let $X$ be some concept or object and $Es(X) = \{e_0, e_1, …, e_n\}$, be the set of essential elements of $X$ ($X$’s essence). Then for some instance of $X$:
$[\forall e \in Es(X), e] \implies X$
In practice however, the assignment of discrete essential elements is often normative, arbitrary or otherwise unclear. This sentiment was echoed by William of Ockham in his 1323 text Summa Logicae. Ockham maintained that “[universals are] not something real that exists in a subject …but that it has a being only as a thought-object in the mind.” Although Sartre holds that non-human objects including “paper [knives]” do have discrete essences, these are products of human intention and design. On the other hand, Sartre argues humans, unlike other objects, are “thrown into this world” without inherent qualities, meaning or purpose. This absence of a predefined essence implies that human beings are responsible for defining their own essence through their choices and actions. Under this definition, existence precedes essence since the essential elements (or human nature) are contingent, being instantiated by the existence of the human. In general, let $H$ be a human and $Es(H)$ be the set of essential elements of $H$ ($H$’s nature). Then for some instance of $H$:
$H \implies [\forall e \in Es(H), e]$
In Existentialism is a Humanism, Sartre presented 3 main arguments to support his existentialism – that “existence precedes essence” in humans. Firstly, he assumes the “atheistic” premise that God does not exist. From this, he deduced that since God does not exist, “there is at least one [necessary] being whose existence comes before its essence”, with that being humans. Parallels can be drawn between this and Aquinas’ contingency argument, which states that all contingent beings must trace back to some necessary being, to avoid infinite recursion. Sartre argues that without a divine creator to prescribe a universal human nature, humans must define themselves through their choices and actions, thus, assuming the position of the necessary existence that bestows essences upon contingent existences, for example paper knives. If humans too, were a contingent existence whose essence precedes existence and there is no God, then it follows that there would exist no necessary existence to provide a finite closure, inducing an infinite regress and undermining the consistency of the atheistic premise. This led Sartre to argue that existentialism is essential for a coherent atheistic worldview. Secondly, he assumes the Cartesian theory of the Cogito, arguing that “every theory [beginning] with man, outside of [the] moment of self-attainment”, is dubious, since action is directly tied to the Cogito itself. According to Sartre, outside of action, all else becomes probabilistic. This means only through intentional acts can one affirm their existence and, by extension, their essence, whereas theoretical assumptions about human nature and the essences of contingent existences, without such actions are unreliable.
