Ontology is the philosophical study of the nature of being, existence or reality as such, as well as 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, and how such entities can be grouped, related within a hierarchy, and subdivided according to similarities and differences.
Ontology, in analytic philosophy, concerns the determining of whether some categories of being are fundamental and asks in what sense the items in those categories can be said to "be". It is the inquiry into being in so much as it is being, or into beings insofar as they exist—and not insofar as, for instance, particular facts obtained about them or particular properties related to them.
Some philosophers, notably of the Platonic school, contend that all nouns (including abstract nouns) refer to existent entities. Other philosophers contend that nouns do not always name entities, but that some provide a kind of shorthand for reference 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. Between these poles of realism and nominalism, there are also a variety of other positions; but any ontology 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, contract, happiness, space, time, truth, causality, and God, ontology becomes fundamental to many branches of philosophy.
Some fundamental questions
Principal questions of ontology are "What can be said to exist?", "Into what categories, if any, can we sort existing things?", "What are the meanings of being?", "What are the various modes of being of entities?". Various philosophers have provided different answers to these questions.
One common approach is to divide the extant subjects and predicates into groups called categories. Of course, such lists of categories differ widely from one another, and it is through the co-ordination of different categorical schemes that ontology relates to such fields as library science and artificial intelligence. Such an understanding of ontological categories, however, is merely taxonomic, classificatory. The categories are, properly speaking,] the ways in which a being can be addressed simply as a being, such as what it is (its 'whatness', quidditas or essence), how it is (its 'howness' or qualitativeness), how much it is (quantitativeness), where it is, its relatedness to other beings, etc.
Further examples of ontological questions include:
- What is existence, i.e. what does it mean for a being to be?
- Is existence a property?
- Is existence a genus or general class that is simply divided up by specific differences?
- Which entities, if any, are fundamental? Are all entities objects?
- How do the properties of an object relate to the object itself?
- What features are the essential, as opposed to merely accidental, attributes of a given object?
- How many levels of existence or ontological levels are there? And what constitutes a 'level'?
- What is a physical object?
- Can one give an account of what it means to say that a physical object exists?
- Can one give an account of what it means to say that a non-physical entity exists?
- What constitutes the identity of an object?
- When does an object go out of existence, as opposed to merely changing?
- Do beings exist other than in the modes of objectivity and subjectivity, i.e. is the subject/object split of modern philosophy inevitable?
Website owlseek.com (http://www.owlseek.com/whatis.html) provides the following definition of ontology:
"We can never know reality in its purest form; we can only interpret it through our senses and experiences.
Therefore, everyone has their own perspective of reality. An ontology is a formal specification of
a perspective. If two people agree to use the same ontology when communicating, then there should be
no ambiguity in the communication. To enable this, an ontology codifies the semantics used to represent
and reason with a body of knowledge."
Ontology - Youtube video Dr. Carolina Acosta-Alzuru 2008 video
Epistemology - Youtube video Dr. Carolina Acosta-Alzuru 2008 video
Ontology - Bibliography
Anselm' Ontological argument on existence of God
http://ontology.buffalo.edu/bfo/BeyondConcepts.pdf (Related to computer science)
The Natures and Tasks of Ontology and Cosmology