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Existence has been variously defined by sources. In common usage, it is the world one is aware or conscious of through one's senses, and that persists independently in one's absence. Other definitions describe it as everything that 'is', or more simply, everything. Some define it to be everything that most people believe in. Aristotle relates the concept to causality.
Ontology is the philosophical study of the nature of being, existence or reality in general, as well as of the basic categories of being and their relations. Traditionally listed as a part of the major branch of philosophy known as metaphysics, ontology deals with questions concerning what entities exist or can be said to exist (for instance: "Does UDFj-39546284 exist?"), and how such entities can be grouped, related within a hierarchy, and subdivided according to similarities and differences. A lively debate continues about the existence of God.
Epistemology studies criteria of truth, defining "primary truths" inherently accepted in the investigation of knowledge. The first is existence. It is inherent in every analysis. Its self-evident, a priori nature cannot be consistently doubted, since a person objecting to existence according to some standard of proof must implicitly accept the standard's existence as a premise.
Life is a characteristic that distinguishes objects that have self-sustaining biological processes from those that do not – either because such functions have ceased (death), or else because they lack such functions and are classified as "inanimate".
The word "existence" comes from the Latin word existere meaning "to appear", "to arise", "to become", or "to be", but literally, it means "to stand out" (ex- being the Latin prefix for "out" added to the Latin verb stare, meaning "to stand").
Historical conceptions 
In the Western tradition of philosophy, the earliest known comprehensive treatments of the subject are from Plato's Phaedo, Republic, and Statesman and Aristotle's Metaphysics, though earlier fragmentary writing exists. Aristotle developed a comprehensive theory of being, according to which only individual things, called substances, fully have being, but other things such as relations, quantity, time, and place (called the categories) have a derivative kind of being, dependent on individual things. In Aristotle's Metaphysics, there are four causes of existence or change in nature: the material cause, the formal cause, the efficient cause, and the final cause.
The Neo-Platonists and some early Christian philosophers argued about whether existence had any reality except in the mind of God. Some taught that existence was a snare and a delusion, that the world, the flesh, and the devil existed only to tempt weak humankind away from God.
The medieval philosopher Thomas Aquinas argued that God is pure being, and that in God essence and existence are the same. At about the same time, the nominalist philosopher William of Ockham argued, in Book I of his Summa Totius Logicae (Treatise on all Logic, written some time before 1327), that Categories are not a form of Being in their own right, but derivative on the existence of individuals.
Early modern philosophy 
The early modern treatment of the subject derives from Antoine Arnauld and Pierre Nicole's Logic, or The Art of Thinking, better known as the Port-Royal Logic, first published in 1662. Arnauld thought that a proposition or judgment consists of taking two different ideas and either putting them together or rejecting them:
After conceiving things by our ideas, we compare these ideas and, finding that some belong together and others do not, we unite or separate them. This is called affirming or denying, and in general judging. This judgment is also called a proposition, and it is easy to see that it must have two terms. One term, of which one affirms or denies something, is called the subject; the other term, which is affirmed or denied, is called the attribute or Praedicatum.
—Antoine Arnauld, The Art of Thinking (Port-Royal Logic),(1662) (translated J. Buroker 1996), Logic, II.3, page 82
The two terms are joined by the verb "is" (or "is not", if the predicate is denied of the subject). Thus every proposition has three components: the two terms, and the "copula" that connects or separates them. Even when the proposition has only two words, the three terms are still there. For example "God loves humanity", really means "God is a lover of humanity", "God exists" means "God is a thing".
This theory of judgment dominated logic for centuries, but it has some obvious difficulties: it only considers proposition of the form "All A are B.", a form logicians call universal. It does not allow propositions of the form "Some A are B", a form logicians call existential. If neither A nor B includes the idea of existence, then "some A are B" simply adjoins A to B. Conversely, if A or B do include the idea of existence in the way that "triangle" contains the idea "three angles equal to two right angles", then "A exists" is automatically true, and we have an ontological proof of A's existence. (Indeed Arnauld's contemporary Descartes famously argued so, regarding the concept "God" (discourse 4, Meditation 5)). Arnauld's theory was current until the middle of the nineteenth century.
David Hume argued that the claim that a thing exists, when added to our notion of a thing, does not add anything to the concept. For example, if we form a complete notion of Moses, and superadd to that notion the claim that Moses existed, we are not adding anything to the notion of Moses.
Kant also argued that existence is not a "real" predicate, but gave no explanation of how this is possible. Indeed, his famous discussion of the subject is merely a restatement of Arnauld's doctrine that in the proposition "God is omnipotent", the verb "is" signifies the joining or separating of two concepts such as "God" and "omnipotence".[original research?]
Schopenhauer claimed that “everything that exists for knowledge, and hence the whole of this world, is only object in relation to the subject, perception of the perceiver, in a word, representation.” According to him there can be "No object without subject" because "everything objective is already conditioned as such in manifold ways by the knowing subject with the forms of its knowing, and presupposes these forms…"
Predicative nature 
John Stuart Mill (and also Kant's pupil Herbart) argued that the predicative nature of existence was proved by sentences like "A centaur is a poetic fiction" or "A greatest number is impossible" (Herbart). Franz Brentano challenged this; so also (as is better known) did Frege. Brentano argued that we can join the concept represented by a noun phrase "an A" to the concept represented by an adjective "B" to give the concept represented by the noun phrase "a B-A". For example, we can join "a man" to "wise" to give "a wise man". But the noun phrase "a wise man" is not a sentence, whereas "some man is wise" is a sentence. Hence the copula must do more than merely join or separate concepts. Furthermore, adding "exists" to "a wise man", to give the complete sentence "a wise man exists" has the same effect as joining "some man" to "wise" using the copula. So the copula has the same effect as "exists". Brentano argued that every categorical proposition can be translated into an existential one without change in meaning and that the "exists" and "does not exist" of the existential proposition take the place of the copula. He showed this by the following examples:
- The categorical proposition "Some man is sick" has the same meaning as the existential proposition "A sick man exists" or "There is a sick man".
- The categorical proposition "No stone is living" has the same meaning as the existential proposition "A living stone does not exist" or "there is no living stone".
- The categorical proposition "All men are mortal" has the same meaning as the existential proposition "An immortal man does not exist" or "there is no immortal man".
- The categorical proposition "Some man is not learned" has the same meaning as the existential proposition "A non-learned man exists" or "there is a non-learned man".
Frege developed a similar view (though later) in his great work The Foundations of Arithmetic, as did Charles Sanders Peirce (but Peirce held that the possible and the real are not limited to the actually, individually existent). The Frege-Brentano view is the basis of the dominant position in modern Anglo-American philosophy: that existence is asserted by the existential quantifier (as expressed by Quine's slogan "To be is to be the value of a variable." — On What There Is, 1948).
In mathematical logic, there are two quantifiers, "some" and "all", though as Brentano (1838–1917) pointed out, we can make do with just one quantifier and negation. The first of these quantifiers, "some", is also expressed as "there exists". Thus, in the sentence "There exists a man", the term "man" is asserted to be part of existence. But we can also assert, "There exists a triangle." Is a "triangle" — an abstract idea — part of existence in the same way that a "man" — a physical body — is part of existence? Do abstractions such as goodness, blindness, and virtue exist in the same sense that chairs, tables, and houses exist? What categories, or kinds of thing, can be the subject or the predicate of a proposition?
Worse, does "existence" exist?
In some statements, existence is implied without being mentioned. The statement "A bridge crosses the Thames at Hammersmith" cannot just be about a bridge, the Thames, and Hammersmith. It must be about "existence" as well. On the other hand, the statement "A bridge crosses the Styx at Limbo" has the same form, but while in the first case we understand a real bridge in the real world made of stone or brick, what "existence" would mean in the second case is less clear.
The nominalist approach is to argue that certain noun phrases can be "eliminated" by rewriting a sentence in a form that has the same meaning, but does not contain the noun phrase. Thus Ockham argued that "Socrates has wisdom", which apparently asserts the existence of a reference for "wisdom", can be rewritten as "Socrates is wise", which contains only the referring phrase "Socrates". This method became widely accepted in the twentieth century by the analytic school of philosophy.
However, this argument may be inverted by realists in arguing that since the sentence "Socrates is wise" can be rewritten as "Socrates has wisdom", this proves the existence of a hidden referent for "wise".
A further problem is that human beings seem to process information about fictional characters in much the same way that they process information about real people. For example, in the 2008 United States presidential election, a politician and actor named Fred Thompson ran for the Republican Party nomination. In polls, potential voters identified Fred Thompson as a "law and order" candidate. Thompson plays a fictional character on the television series Law and Order. Doubtless the people who make the comment are aware that Law and Order is fiction, but at some level, they process fiction as if it were fact.[dubious ] Another example of this is the common experience of actresses who play the villain in a soap opera being accosted in public as if they are to blame for the actions of the characters they play.
A scientist might make a clear distinction about objects that exist, and assert that all objects that exist are made up of either matter or energy. But in the layperson's worldview, existence includes real, fictional, and even contradictory objects. Thus if we reason from the statement "Pegasus flies" to the statement "Pegasus exists", we are not asserting that Pegasus is made up of atoms, but rather that Pegasus exists in a particular worldview, the worldview of classical myth. When a mathematician reasons from the statement "ABC is a triangle" to the statement "triangles exist", she is not asserting that triangles are made up of atoms but rather that triangles exist within a particular mathematical model.
Modern approaches 
According to Bertrand Russell's Theory of Descriptions, the negation operator in a singular sentence can take either wide or narrow scope: we distinguish between "some S is not P" (where negation takes "narrow scope") and "it is not the case that 'some S is P'" (where negation takes "wide scope"). The problem with this view is that there appears to be no such scope distinction in the case of proper names. The sentences "Socrates is not bald" and "it is not the case that Socrates is bald" both appear to have the same meaning, and they both appear to assert or presuppose the existence of someone (Socrates) who is not bald, so that negation takes narrow scope. However, Russell's theory analyses proper names into a logical structure which makes sense of this problem. According to Russell Socrates can be analysed into the form 'The Philosopher of Greece.' In the wide scope this would then read: It is not the case that there existed a philosopher of Greece who was bald. In the narrow scope it would read the Philosopher of Greece was not bald.
According to the direct-reference view, an early version of which was originally proposed by Bertrand Russell, and perhaps earlier by Gottlob Frege, a proper name strictly has no meaning when there is no object to which it refers. This view relies on the argument that the semantic function of a proper name is to tell us which object bears the name, and thus to identify some object. But no object can be identified if none exists. Thus, a proper name must have a bearer if it is to be meaningful.
Existence cannot be subject to "creation" AND also be eternal. All experiments favor eternal, as does the Law of Conservation of Matter and Energy. Arguing "creation" goes against the accepted definition of time as a statistic. One can talk of a unit for matter, like an atom or apple, and quantify how much potential and kinetic energy it has, but space and time have no unit - no identity.
Existence in the wide and narrow senses 
According to the "two sense" view of existence, which derives from Alexius Meinong, existential statements fall into two classes.
- Those asserting existence in a wide sense. These are typically of the form "N is P" for singular N, or "some S is P".
- Those asserting existence in a narrow sense. These are typically of the form "N exists" or "Ss exist".
The problem is then evaded as follows. "Pegasus flies" implies existence in the wide sense, for it implies that something flies. But it does not imply existence in the narrow sense, for we deny existence in this sense by saying that Pegasus does not exist. In effect, the world of all things divides, on this view, into those (like Socrates, the planet Venus, and New York City) that have existence in the narrow sense, and those (like Sherlock Holmes, the goddess Venus, and Minas Tirith) that do not.
However, common sense suggests the non-existence of such things as fictional characters or places.
European views 
Anti-realist arguments 
Anti-realism is the view of idealists who are skeptics about the physical world, maintaining either: 1) that nothing exists outside the mind, or 2) that we would have no access to a mind-independent reality even if it may exist. Realists, in contrast, hold that perceptions or sense data are caused by mind-independent objects. An "anti-realist" who denies that other minds exist (i. e., a solipsist) is different from an "anti-realist" who claims that there is no fact of the matter as to whether or not there are unobservable other minds (i. e., a logical behaviorist).
The Ania conclusion 
The Ania conclusion was made by a council of Greek scholars in the third century BCE. The council was called to gather evidence and thoughts to organize an answer to one of the root questions: why does anything exist? By some accounts, they succeeded, and their conclusion was so startling that it broke the mind of many a man. All the scholars were executed and the conclusion was lost forever. In other accounts, the conclusion was wholly underwhelming and the scholars were condemned. Why it is referred to as "the Ania conclusion" in texts is unknown.
Dharmic "middle way" view 
In eastern philosophy, Anicca (Sanskrit anitya) or "impermanence" describes existence. It refers to the fact that all conditioned things (sankhara) are in a constant state of flux. In reality there is no thing that ultimately ceases to exist; only the appearance of a thing ceases as it changes from one form to another. Imagine a leaf that falls to the ground and decomposes. While the appearance and relative existence of the leaf ceases, the components that formed the leaf become particulate material that goes on to form new plants. Buddhism teaches a middle way, avoiding the extreme views of eternalism and nihilism. The middle way recognizes there are vast differences between the way things are perceived to exist and the way things really exist. The differences are reconciled in the concept of Shunyata by addressing the existing object's served purpose for the subject's identity in being. What exists is in non-existence, because the subject changes.
Trailokya elaborates on three kinds of existence, those of desire, form, and formlessness in which there are karmic rebirths. Taken further to the Trikaya doctrine, it describes how the Buddha exists. In this philosophy, it is accepted that the Buddha exists in more than one absolute way.
See also 
- Cogito ergo sum
- Conservation law
- Cosmological argument
- Existence precedes essence
- Existence theorem
- Existential operator
- Gödel's ontological proof
- Gaunilo of Marmoutiers
- Identity and change
- Meaning of life
- Performative contradiction
- Right to exist
- Three marks of existence
- "Definition of EXISTENCE". Merriam-Webster. Retrieved 29 September 2012.
- Dolhenty, Jonathan. "Part Thirteen:The Criterion of Truth". The Problem of Knowledge: A brief introduction to epistemology. Retrieved 2007-10-31.[dead link]
- Koshland Jr, Daniel E. (March 22, 2002). "The Seven Pillars of Life". Science 295 (5563): 2215–2216. doi:10.1126/science.1068489. PMID 11910092. Retrieved 2009-05-25.
- The American Heritage Dictionary of the English Language, 4th edition, published by Houghton Mifflin Company, via Answers.com:
- "The property or quality that distinguishes living organisms from dead organisms and inanimate matter, manifested in functions such as metabolism, growth, reproduction, and response to stimuli or adaptation to the environment originating from within the organism."
- "The characteristic state or condition of a living organism."
- Definition of inanimate. WordNet Search by Princeton University.
- The World as Will and Representation, vol. I, § 1
- The World as Will and Representation, vol. I, § 7
- John Stuart Mill, A System of Logic, 1843 I. iv. 1.page 124
- Uberweg (System of Logic) §68
- On What There Is - in Review of Metaphysics (1948). Reprinted in W.V.O. Quine, From a Logical Point of View (Harvard University Press, 1953)
- To exist is to have a specific relation to existence - a relation, by the way, which existence itself does not have. Bertrand Russell - The Principles of Mathematics - New York, W. W. Norton & Company, 1903, second edition 1937 pages 449-450.
- The Buddhist Publication Society. "The Three Basic Facts of Existence". Retrieved 2009-07-14. "(ref.1) Change or impermanence is the essential characteristic of all phenomenal existence. We cannot say of anything, animate or inanimate, organic or inorganic, "this is lasting"; for even while we are saying this, it would be undergoing change. All is fleeting; the beauty of flowers, the bird's melody, the bee's hum, and a sunset's glory."
- Antoine Arnauld and Pierre Nicole Logic, or the Art of Thinking, (known as the Port-Royal Logic), translated J. Buroker, Cambridge 1996
- Mill, J.S., A System of Logic, 8th edition 1908
- Loux, M., Ockham's Theory Of Terms (translation of book I of the Summa Logicae c-1327).
- Plato, The Republic, translated by Desmond Lee, Penguin Classics, 2003, ISBN 0-14-044914-0, ISBN 978-0-14-044914-3
- Aristotle, The Metaphysics, translated by Hugh Lawson-Tancred, Penguin Classics, 1999, ISBN 0-14-044619-2, ISBN 978-0-14-044619-7
- Heraclitus, Fragments, James Hilton, forward, Brooks Hexton, translator, Penguin Classics, 2003, ISBN 0-14-243765-4, ISBN 978-0-14-243765-0.
- The Meaning of Life, Terry Eagleton, Oxford University Press, 2007, ISBN 0-19-921070-5 ISBN 978-0-19-921070-1
- The Story of Philosophy, Bryan Magee, Dorling Kindersley Lond. 1998, ISBN 0-7513-0590-1
- What is Existence?, C.J.F. Williams, Oxford University Press, 1981
|Look up existence in Wiktionary, the free dictionary.|
- Existence entry by Michael Nelson in the Stanford Encyclopedia of Philosophy, 2012-10-11
- The Concept of Existence: History and Definitions from Leading Philosophers
- "A Treatise on Book Titles" is a work by Sayf al-Din al-Amidi, in Arabic, about "original" and "mental existence". It dates from 1805.