Ontology
Ontology is the philosophical study of being. It is traditionally understood as the subdiscipline of metaphysics focused on the most general features of reality. As one of the most fundamental concepts, being encompasses all of reality and every entity within it. To articulate the basic structure of being, ontology examines the commonalities among all things and investigates their classification into basic types, such as the categories of particulars and universals. Particulars are unique, non-repeatable entities, such as the person Socrates, whereas universals are general, repeatable entities, like the color green. Another distinction exists between concrete objects existing in space and time, such as a tree, and abstract objects existing outside space and time, like the number 7. Systems of categories aim to provide a comprehensive inventory of reality by employing categories such as substance, property, relation, state of affairs, and event.
Ontologists disagree regarding which entities exist at the most basic level. Platonic realism asserts that universals have objective existence, while conceptualism maintains that universals exist only in the mind, and nominalism denies their existence altogether. Similar disputes pertain to mathematical objects, unobservable objects assumed by scientific theories, and moral facts. Materialism posits that fundamentally only matter exists, whereas dualism asserts that mind and matter are independent principles. According to some ontologists, objective answers to ontological questions do not exist, with perspectives shaped by differing linguistic practices.
Ontology employs diverse methods of inquiry, including the analysis of concepts and experience, the use of intuitions and thought experiments, and the integration of findings from natural science. Formal ontology investigates the most abstract features of objects, while applied ontology utilizes ontological theories and principles to study entities within specific domains. For example, social ontology examines basic concepts used in the social sciences. Applied ontology is particularly relevant to information and computer science, which develop conceptual frameworks of limited domains. These frameworks facilitate the structured storage of information, such as in a college database tracking academic activities. Ontology is also pertinent to the fields of logic, theology, and anthropology.
The origins of ontology lie in the ancient period with speculations about the nature of being and the source of the universe, including ancient Indian, Chinese, and Greek philosophy. In the modern period, philosophers conceived ontology as a distinct academic discipline and coined its name.
Definition
Ontology is the study of being. It is the branch of philosophy that investigates the nature of existence, the features all entities have in common, and how they are divided into basic categories of being. It aims to discover the foundational building blocks of the world and characterize reality as a whole in its most general aspects. In this regard, ontology contrasts with individual sciences like biology and astronomy, which restrict themselves to a limited domain of entities, such as living entities and celestial phenomena. In some contexts, the term ontology refers not to the general study of being but to a specific ontological theory within this discipline. It can also mean an inventory or a conceptual scheme of a particular domain, such as the ontology of genes. In this context, an inventory is a comprehensive list of elements. A conceptual scheme is a framework of the key concepts and their relationships.Ontology is closely related to metaphysics but the exact relation of these two disciplines is disputed. A traditionally influential characterization asserts that ontology is a subdiscipline of metaphysics. According to this view, metaphysics is the study of various aspects of fundamental reality, whereas ontology restricts itself to the most general features of reality. This view sees ontology as general metaphysics, which is to be distinguished from special metaphysics focused on more specific subject matters, like God, mind, and value. A different conception understands ontology as a preliminary discipline that provides a complete inventory of reality while metaphysics examines the features and structure of the entities in this inventory. Another conception says that metaphysics is about real being while ontology examines possible being or the concept of being. It is not universally accepted that there is a clear boundary between metaphysics and ontology. Some philosophers use both terms as synonyms.
The etymology of the word ontology traces back to the ancient Greek terms ὄντως and λογία, literally,. The ancient Greeks did not use the term ontology, which was coined by philosophers in the 17th century.
Basic concepts
Being
Being, or existence, is the main topic of ontology. It is one of the most general and fundamental concepts, encompassing all of reality and every entity within it. In its broadest sense, being only contrasts with non-being or nothingness. It is controversial whether a more substantial analysis of the concept or meaning of being is possible. One proposal understands being as a property possessed by every entity. Critics argue that a thing without being cannot have properties. This means that properties presuppose being and cannot explain it. Another suggestion is that all beings share a set of essential features. According to the Eleatic principle, "power is the mark of being", meaning that only entities with causal influence truly exist. A controversial proposal by philosopher George Berkeley suggests that all existence is mental. He expressed this immaterialism in his slogan "to be is to be perceived".Depending on the context, the term being is sometimes used with a more limited meaning to refer only to certain aspects of reality. In one sense, being is unchanging and permanent, in contrast to becoming, which implies change. Another contrast is between being, as what truly exists, and phenomena, as what appears to exist. In some contexts, being expresses the fact that something is while essence expresses its qualities or what it is like.
Ontologists often divide being into fundamental classes or highest kinds, called categories of being. Proposed categories include substance, property, relation, state of affairs, and event. They can be used to provide systems of categories, which offer a comprehensive inventory of reality in which every entity belongs to exactly one category. Some philosophers, like Aristotle, say that entities belonging to different categories exist in distinct ways. Others, like John Duns Scotus, insist that there are no differences in the mode of being, meaning that everything exists in the same way. A related dispute is whether some entities have a higher degree of being than others, an idea already found in Plato's work. The more common view in contemporary philosophy is that a thing either exists or not with no intermediary states or degrees.
The relation between being and non-being is a frequent topic in ontology. Influential issues include the status of nonexistent objects and why there is something rather than nothing.
Particulars and universals
A central distinction in ontology is between particular and universal entities. Particulars, also called individuals, are unique, non-repeatable entities, like Socrates, the Taj Mahal, and Mars. Universals are general, repeatable entities, like the color green, the form circularity, and the virtue courage. Universals express aspects or features shared by particulars. For example, Mount Everest and Mount Fuji are particulars characterized by the universal mountain.Universals can take the form of properties or relations. Properties describe the characteristics of things. They are features or qualities possessed by an entity. Properties are often divided into essential and accidental properties. A property is essential if an entity must have it; it is accidental if the entity can exist without it. For instance, having three sides is an essential property of a triangle, whereas being red is an accidental property. Relations are ways how two or more entities stand to one another. Unlike properties, they apply to several entities and characterize them as a group. For example, being a city is a property while being east of is a relation, as in "Kathmandu is a city" and "Kathmandu is east of New Delhi". Relations are often divided into internal and external relations. Internal relations depend only on the properties of the objects they connect, like the relation of resemblance. External relations express characteristics that go beyond what the connected objects are like, such as spatial relations.
Substances play an important role in the history of ontology as the particular entities that underlie and support properties and relations. They are often considered the fundamental building blocks of reality that can exist on their own, while entities like properties and relations cannot exist without substances. Substances persist through changes as they acquire or lose properties. For example, when a tomato ripens, it loses the property green and acquires the property red.
States of affairs are complex particular entities that have several other entities as their components. The state of affairs "Socrates is wise" has two components: the individual Socrates and the property wise. States of affairs that correspond to reality are called facts. Facts are truthmakers of statements, meaning that whether a statement is true or false depends on the underlying facts.
Events are particular entities that occur in time, like the fall of the Berlin Wall and the first moon landing. They usually involve some kind of change, like the lawn becoming dry. In some cases, no change occurs, like the lawn staying wet. Complex events, also called processes, are composed of a sequence of events.