Ontology

• 1. Introduction

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  Ontology asks the question that sits underneath every other question: what does it mean for something to exist? The person Socrates exists. So does the color green. So does the number 7, the One Ring from a book series, and the thought you have when you picture the Loch Ness Monster. But do all of these exist in the same way, or at all? Ontology is the philosophical study of being, traditionally treated as the part of metaphysics concerned with the most general features of reality. The ancient Greeks speculated about being for centuries, yet never used the word. It was coined far later, by philosophers in the 17th century. This documentary follows that long road. It asks why thinkers disagree so sharply about which things truly exist, how they sort reality into basic categories, and why a question this abstract now shapes the databases that store our genes, our proteins, and our friends.

• 2. The Question Of Being

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  Being, in its broadest sense, contrasts with only one thing: non-being, or nothingness. Whether being can be analyzed any further is itself controversial. One proposal treats being as a property that every entity possesses. Critics counter that a thing without being could not have properties at all, so properties presuppose being rather than explaining it. The Eleatic principle offers another route, holding that power is the mark of being, so only entities with causal influence truly exist. George Berkeley pushed further still, arguing that all existence is mental, a view he captured in the slogan that to be is to be perceived.

  Depending on context, the word being narrows. In one sense it names what is unchanging and permanent, set against becoming, which implies change. In another, it names what truly exists, set against phenomena, which merely appear to exist. Some thinkers separate being, the fact that something is, from essence, which describes what that something is like.

  Aristotle held that entities in different categories exist in distinct ways. John Duns Scotus disagreed, insisting there are no differences in the mode of being, so everything exists in the same way. A related quarrel asks whether some things possess a higher degree of being than others, an idea already present in Plato's work. The more common contemporary view is starker: a thing either exists or it does not, with no intermediate states. That leaves ontology with its strangest puzzles, including the status of nonexistent objects and the question of why there is something rather than nothing.

• 3. Particulars And Universals

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  Socrates, the Taj Mahal, and Mars are particulars: unique, non-repeatable entities. The color green, the form circularity, and the virtue courage are universals: general, repeatable entities that express features shared by many particulars. Mount Everest and Mount Fuji are each particulars, characterized by the universal mountain.

  Universals split into properties and relations. A property is a quality an entity has, and properties divide into essential and accidental kinds. Having three sides is essential to a triangle, while being red is accidental. Relations, by contrast, connect two or more entities and describe them as a group. Being a city is a property, as in the claim that Kathmandu is a city, while being east of is a relation, as in the claim that Kathmandu is east of New Delhi. Relations themselves divide into internal ones, which depend only on the properties of the things they connect, like resemblance, and external ones, like spatial position, which reach beyond what those things are like.

  Substances carry special weight in this scheme as the particulars that underlie and support properties and relations. They can exist on their own, while properties and relations cannot exist without them, and they persist through change. When a tomato ripens, it loses the property green and gains the property red, yet remains the same substance.

  States of affairs are complex particulars built from other entities. The state of affairs that Socrates is wise has two components, the individual Socrates and the property wise. When a state of affairs corresponds to reality, it is called a fact, and facts serve as the truthmakers that decide whether statements are true or false. Events occupy time and usually involve change, like the fall of the Berlin Wall, the first moon landing, or a lawn drying out. String enough events together in sequence and you have a process.

• 4. Concrete And Abstract

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  A tree, a car, and a planet are concrete objects: they sit in space and time and carry causal powers. When a car hits a tree, both are deformed. The number 7 and the set of integers are abstract objects, lying outside space and time, lacking causal powers, and never changing. Whether such things truly exist remains a matter of debate.

  Everyday concrete objects are layered. A book is two covers and the pages between them, and each page is built from molecules, atoms, and elementary particles. Mereology studies how parts relate to wholes. One view says any collection of entities forms a whole; another restricts wholes to collections that meet some condition, such as touching one another. The problem of material constitution then asks whether the whole is really a new object on top of its parts.

  Abstract objects shade into fictional and intentional ones. Fictional objects are invented in works of fiction, like the One Ring in J. R. R. Tolkien's The Lord of the Rings or the Monkey King in Journey to the West. Some philosophers treat them as abstract objects beyond space and time; others see them as artifacts created when the fiction is written. Intentional objects live inside mental states. Think about the Loch Ness Monster and that creature becomes the intentional object of your thought, whether or not it exists anywhere else. Because people can think about things that do not exist, the ontological status of intentional objects is hard to pin down.

• 5. Dependence Identity And Modality

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  The surface of an apple cannot exist without the apple, and that simple fact names a deep relation: ontological dependence. An entity that depends on nothing else is ontologically independent, fundamental, able to stand on its own. This relation is closely tied to metaphysical grounding, which links a ground to the facts it explains.

  An ontological commitment is whatever exists according to a person or a theory. Someone who believes in God carries an ontological commitment to God. Such commitments help reveal which ontologies people defend or quietly assume. The Quine-Putnam indispensability argument uses them to defend mathematical Platonism, reasoning that numbers exist because the best scientific theories are committed to numbers.

  Possibility describes what can be the case, necessity what must be the case, and actuality what is the case, as in the claim that Doha is the capital of Qatar. Ontologists analyze the first two through possible worlds, each a complete and consistent way things could have been. Haruki Murakami was born in 1949 in the actual world, but in some possible world he was born on a different date. A sentence counts as possibly true if it holds in at least one possible world, and necessarily true if it holds in all of them. Modal logic supplies the precise formalization.

  Identity means that two things are the same, and it comes in kinds. Qualitatively identical things share every feature, like perfect identical twins. Numerically identical things are a single entity, so if Fatima is the mother of both Leila and Hugo, then Leila's mother is numerically identical to Hugo's. Synchronic identity relates an entity to itself at one time; diachronic identity relates it across times. Saul Kripke argued that discovered identities such as Water is H2O are necessarily true, because H2O is a rigid designator.

• 6. Mapping The Branches

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  Pure ontology chases the most abstract questions about the nature of being, taking in existence and the structure of reality as a whole. Applied ontology, also called domain ontology, turns those theories onto specific fields, examining problems about matter, mind, numbers, God, and cultural artifacts. Social ontology, a major branch of the applied side, studies social kinds like money, gender, society, and language, often treating them as useful constructions that are neither pure fictions nor as mind-independent as lions or stars.

  Formal ontology studies objects in general, sorting them by the abstract forms they exemplify and leaning on the tools of formal logic. It contrasts with material ontology, which examines features specific to an area, like ideal spatial beings in geometry or living beings in biology. Descriptive ontology articulates how people ordinarily think about the world, while prescriptive ontology departs from common conceptions to build a better one.

  Analytic ontology asks what kinds of things could exist and what features they would have. Speculative ontology asks which entities actually exist, whether there are numbers or whether time is an illusion. Above all of these sits meta-ontology, which does not ask what exists but what it means for something to exist and how anyone could determine the answer. It runs close to fundamental ontology, the approach Martin Heidegger developed to uncover the meaning of being.

• 7. The Realism Wars

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  Ontological realism holds that there are objective, mind-independent facts about what exists and what the categories of being are, without saying what those facts are. Its opponents, the ontological anti-realists or deflationists, deny any substantive facts in the matter. Rudolf Carnap argued that ontological statements are relative to language and depend on the speaker's framework, so no framework can be objectively right or wrong.

  Realism about universals splits along fine lines. Platonic realists say universals exist independent of the mind and independent of the objects that exemplify them, so the universal red could exist with no red objects at all. Aristotelian realism, also called moderate realism, says universals exist only while exemplifying objects do. Conceptualism replies that universals exist only in the mind as concepts, and nominalists go furthest, denying universals any existence, leaving a world of particular objects alone.

  The same battle line runs through mathematics. Mathematical Platonists say numbers and sets are as real as atoms and stars, even though no observation can reach them. Conventionalism counters that mathematical theories are trivially true by definition, while game formalism treats mathematics as a game of string manipulation. Modal realism extends the fight to possible worlds, holding that countless other worlds are as real and concrete as ours, inhabited by our counterparts. Scientific realists insist that science accurately describes reality, including unobservable electrons, forces, and laws of nature, while moral realists claim there are mind-independent moral facts, against relativists and nihilists who deny them.

• 8. Building Blocks And Applications

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  Substance-attribute ontology says reality is built at bottom from unanalyzable substances characterized by universals. The related substratum theory adds a featureless bare particular beneath the properties, a substratum that supports them while having none of its own. Rivals reject substances entirely. Stuff ontologies fill space with continuous, infinitely divisible stuff. Process ontology makes processes and events fundamental, insisting that being is dynamic and never static. Bundle theories dissolve objects into bundles of co-present properties, so a lemon is just yellow, sour, and round gathered together. Relationalism makes reality relational all the way down, and ontic structural realism builds complex structures from those relations, with some versions denying individual objects altogether. Fact ontologies make states of affairs the fundamental constituents, so the Earth being a planet joins the object Earth to the property being a planet.

  Systems of categories stretch back through history. Aristotle proposed ten: substance, quantity, quality, relation, place, date, posture, state, action, and passion. The Vaisheshika school in Indian philosophy named six, including substance, quality, motion, universal, individuator, and inherence. Immanuel Kant's transcendental idealism set out twelve pure concepts of understanding, grouped into quantity, quality, relation, and modality.

  This abstract machinery now does concrete work. In computer and information science, applied ontology builds formal frameworks to encode information about a limited domain, using categories like person, company, address, and name to fill a database. Upper ontologies such as the Suggested Upper Merged Ontology and Basic Formal Ontology span many domains so distinct databases can be integrated. Gene Ontology, Sequence Ontology, and Protein Ontology standardize biological information across species and databases, Environment Ontology maps ecosystems, and Friend of a Friend represents relations between people and their activities. The 17th-century coinage now sits inside the systems that catalog living things.