Existence is the state of being real or participating in reality. The terms "being", "reality", and
"actuality" are often used as close synonyms. Existence contrasts with nonexistence, nothingness,
and nonbeing. A common distinction is between the existence of an entity and its essence, which
refers to the entity's nature or essential qualities.
The main philosophical discipline studying existence is called ontology. The orthodox view is that it is
a second-order property or a property of properties. According to this view, to say that a thing exists
means that its properties are instantiated. A different view holds that existence is a first-order
property or a property of individuals. This means that existence has the same ontological status as
other properties of individuals, like color and shape. Meinongians accept this idea and hold that not
all individuals have this property: they state that there are some individuals that do not exist. This
view is rejected by universalists, who see existence as a universal property of every individual.
Various types of existence are discussed in the academic literature. Singular existence is the
existence of individual entities while general existence refers to the existence
of concepts or universals. Other distinctions are between abstract and concrete existence, between
possible, contingent, and necessary existence, and between physical and mental existence. A
closely related issue is whether different types of entities exist in different ways or to different
degrees.
A key question in ontology is whether there is a reason for existence in general or why anything at all
exists. The concept of existence is relevant to various fields,
including logic, epistemology, philosophy of mind, philosophy of language, and existentialism.
Definition and related terms[edit]
Existence is the state of being real. To exist means to have being or to participate
in reality.[1] Existence is what sets real entities apart from imaginary ones.[2] It can refer both to
individual entities or to the totality of reality.[3] The word "existence" entered the English language in
the late 14th century from old French. It has its roots in the medieval Latin term ex(s)istere, which
means to stand forth, to appear, and to arise.[4] Existence is studied by the subdiscipline
of metaphysics known as ontology.[5]
The terms "being", "reality", and "actuality" are closely related to existence.[6] They are usually used
as synonyms of "existence" but their meanings as technical terms may come apart.[7] According to
metaphysicist Alexius Meinong, for example, all entities have being but not all have existence. He
argues that merely possible objects, like Santa Claus, have being but lack existence.[8] Ontologist
Takashi Yagisawa contrasts existence with reality. He sees "reality" as the more fundamental term
since it characterizes all entities equally. He defines existence as a relative term that connects an
entity to the world that it inhabits.[9] According to Gottlob Frege, actuality is more narrow than
existence. He holds that actual entities can produce and undergo changes. He states that some
existing entities are non-actual, like numbers and sets.[10]
Existence contrasts with nonexistence, which refers to a lack of reality. It is controversial whether
objects can be divided into existent and nonexistent objects. This distinction is sometimes used to
explain how it is possible to think of fictional objects, like dragons and unicorns. But the concept of
nonexistent objects is not generally accepted.[11] Closely related contrasting terms
are nothingness and nonbeing.[12]
Another contrast is between existence and essence. Essence refers to the intrinsic nature or
defining qualities of an entity. The essence of something determines what kind of entity it is and how
it differs from other kinds of entities. Essence corresponds to what an entity is while existence
corresponds to the fact that it is. For instance, it is possible to understand what an object is and
grasp its nature even if one does not know whether this object exists.[13]
Some philosophers, like Edmund Husserl and Quentin Boyce Gibson, hold that existence is an
elementary concept. This means that it cannot be defined in other terms without involving circularity.
This would imply that it may be difficult or impossible to characterize existence or to talk about its
nature in a non-trivial manner.[14]
A closely related issue concerns the distinction between thin and thick concepts of existence. Thin
concepts understand existence as a logical property that every existing thing shares. It does not
include any substantial content about the metaphysical implications of having existence. An example
of a thin concept of existence is to state that existence is the same as the logical property of selfidentity.[15] Thick concepts of existence encompass a metaphysical analysis of what it means that
something exists and what essential features existence implies. For example, George Berkeley's
claim that esse est percipi presents a thick concept of existence. It can be translated as "to be is to
be perceived" and highlights the mental nature of all existence.[16]
Some philosophers emphasize that there is a difference between entities and what fundamentally
makes them the entities they are.[17] This distinction was introduced by Martin Heidegger, who calls it
the ontological difference and contrasts individual beings with being, the latter of which he presents
as the horizon against which beings become the specific beings that they are.[18][a]
Theories of the nature of existence[edit]
One of the topics covered by theories of the nature of existence concerns the ontological status of
fictional objects like Pegasus.[20]
Theories of the nature of existence aim to explain what it means for something to exist. The central
dispute regarding the nature of existence is whether it should be understood as
a property of individuals.[21]
The two main theories of existence are first-order theories and second-order theories. First-order
theories understand existence as a property of individuals. Some first-order theories see it as a
property of all individuals while others hold that there are some individuals that do not exist. Secondorder theories hold that existence is a second-order property, that is, a property of properties.[22]
A central challenge for the different theories of the nature of existence is to understand how it is
possible to coherently deny the existence of something. An example is the sentence "Santa Claus
does not exist". One difficulty consists in explaining how the name "Santa Claus" can be meaningful
even though there is no Santa Claus.[23]