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This article discusses ontology in philosophy. For the term in computer science, see ontology (computer science).

In philosophy, ontology (from the Greek ων = being and λόγος = word/speech) is the most fundamental branch of metaphysics. It studies being or existence as well as the basic categories thereof -- trying to find out what entities and what types of entities exist. Ontology has strong implications for the conceptions of reality.

Some philosophers, notably of the Platonic school, contend that all nouns refer to entities. Other philosophers contend that some nouns do not name entities but provide a kind of shorthand way of referring to a collection (of either objects or events). In this latter view, mind, instead of referring to an entity, refers to a collection of mental events experienced by a person; society refers to a collection of persons with some shared characteristics, and geometry refers to a collection of a specific kind of intellectual activity. Any ontology then must give an account of which words refer to entities, which do not, why, and what categories result. When one applies this process to nouns such as electrons, energy, promise, happiness, time, truth, causality, and god, ontology becomes fundamental to many branches of philosophy.


Some basic questions

Ontology has as one of its basic questions: "What are the fundamental categories of being?" Different philosophers make different lists of such fundamental categories of being.

This highlights one of the problems of the philosophical approach — it relies on continued investigation of categories, and has no clear way to stop asking. Whereas, in theology and library science and artificial intelligence, one typically adopts a relatively stable foundation ontology. This reflects a larger cosmology and probably morals, aesthetic examples or stories; all of which can set foundational priorities. In theology this derives from a religion and its (relatively) stable doctrines.

Further examples of ontological questions include:

  1. What is existence?
  2. What are physical objects?
  3. What are the essential, as opposed to merely accidental, attributes of a given object?
  4. What constitutes the Identity of an object?
  5. Can one give an account of what it means to say that a physical object exists?
  6. What are an object's properties or relations and how are they related to the object itself?
  7. Is existence a property?
  8. When does an object go out of existence, as opposed to merely changing?
  9. Why does something exist rather than nothing?

Some concepts

A few quintessential ontological concepts include:

Early history of ontology

The concept of ontology originated in early Greece and occupied Plato and Aristotle. Aristotle described ontology as "the science of being qua being". The word 'qua' means 'with regard to the aspect of'. According to this theory, then, ontology is the science of being with regard to the aspect of being, or the study of beings insofar as they exist. More precisely, ontology concerns determining what categories of being are fundamental and asks whether, and in what sense, the items in those categories can be said to "be".

Subject, relationship, object

"What exists", "What is", "What am I", "What is describing this to me", all exemplify questions about being, and highlight the most basic problem in ontology: finding a subject, a relationship, and an object to talk about. During the Enlightenment the view of René Descartes that "cogito ergo sum" (or "I think therefore I am") had generally prevailed, although Descartes himself did not believe the question worthy of any deep investigation. However, Descartes was very religious in his philosophy, and indeed argued that "cogito ergo sum" proved the existence of God. Later theorists would note the existence of the "Cartesian Other" — asking "who is reading that sentence about thinking and being?" — and generally concluded that it must be God.

This answer, however, became increasingly unsatisfactory in the 20th century as the philosophy of mathematics and the philosophy of science and even particle physics explored some of the most fundamental barriers to knowing about being.

Body and environment

Schools of subjectivism, objectivism and relativism existed at various times in the 20th century, and the postmodernists and body philosophers tried to reframe all these questions in terms of bodies taking some specific action in an environment. This relied to a great degree on insights derived from scientific research into animals taking instinctive action in natural and artificial settings — as studied by biology, ecology, and cognitive science.

The processes by which bodies related to environments became of great concern, and the idea of being itself became difficult to really define. What did people mean when they said "A is B", "A must be B", "A was B"...? Some linguists advocated dropping the verb "to be" from the English language, leaving "E Prime", supposedly less prone to bad abstractions. Others, mostly philosophers, tried to dig into the word and its usage. Heidegger attempted to distinguish being and existence.


Existentialism regards being as a fundamental central concept. It is anything that can be said to 'be' in various senses of the word 'be'. The verb to be has many different meanings and can therefore be rather ambiguous. Because "to be" has so many different meanings, there are, accordingly, many different ways of being.

Prominent ontologists

Related articles

External links

Last updated: 10-14-2005 10:52:33
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