---
title: Existence and Being
section-id: metaphysics
sort: 100
author: Prof. James Okafor
created: 2026-02-03 09:00
modified: 2026-03-10 11:00
language: en
description: What does it mean to say that something exists? Ontology and the question of being.
---

# Existence and Being

Metaphysics is the branch of philosophy concerned with the most fundamental features of reality. It asks questions that science presupposes rather than answers: What exists? What is it for something to exist? What are the basic categories of things that exist? This chapter introduces the central questions of ontology—the theory of being.

## The Existential Question

Gottlob Frege and Bertrand Russell brought modern rigour to the question of existence. Russell’s analysis of ‘The present king of France is bald’ showed that apparently referring phrases need not refer to anything. ‘Exists’ is not a predicate that describes an object; it is a second-order predicate applied to concepts. To say ‘horses exist’ is to say the concept *horse* has instances.

W.V.O. Quine systematised this into a **criterion of ontological commitment**: to be is to be the value of a bound variable. If a theory is true and its truth requires that there are objects of a certain kind (entities that must be quantified over), then the theory is committed to those objects’ existence. Ontological questions become questions about what we must quantify over in our best scientific theories.

## What Kinds of Things Exist?

### Concrete and Abstract Objects
Most philosophers distinguish **concrete objects** (physical things that occupy space and time, have causal powers) from **abstract objects** (numbers, properties, propositions, which are not located in space and time). The existence of abstract objects is contested.

**Platonism** holds that abstract objects genuinely exist, independently of minds and language. Mathematical truths are discovered, not invented. This explains the applicability of mathematics to the physical world and the objectivity of mathematical truth, but raises the difficult question of how we can have knowledge of entities that are not in causal contact with us.

**Nominalism** denies that abstract objects exist. Numbers, properties, and propositions are either convenient fictions or reducible to something concrete (patterns, linguistic expressions, collections of physical things). Nominalism avoids the epistemological problem but must explain how mathematical truth and applicability are possible without abstract objects.

### Universals and Particulars
The problem of **universals** concerns the status of properties shared by multiple individuals. Two red things share the property of redness. What is this property?

- **Realists** hold that universals (properties, relations) exist in addition to particulars. Redness is something the two objects share.
- **Nominalists** deny that universals exist. Calling two things ‘red’ is a matter of applying the same word to them (linguistic nominalism) or their belonging to the same resemblance class (resemblance nominalism)—not of their sharing an entity.
- **Trope theory** holds that each property instance is a particular—this redness and that redness are distinct entities that merely resemble each other.

## Existence and Non-Existence

What about things that do not exist—fictional characters, impossible objects, entities we merely imagine? It seems we can think and speak about Sherlock Holmes even though he does not exist. What is the object of such thought?

**Meinongianism** (after Alexius Meinong) holds that there are non-existent objects: they have a kind of being (subsistence) even though they do not exist. Critics find this ontologically profligate.

Russell’s theory of descriptions eliminates non-existent objects. ‘Sherlock Holmes is a detective’ should be analysed as a claim about the story, or as false (in the real world, nothing is both Holmes and a detective). We do not need to posit non-existent objects.

## Ontological Categories

What are the most basic categories of being? Aristotle distinguished substances (independent things), accidents (properties that depend on substances), and relations. Contemporary ontologists discuss categories including:

- **Objects** (particulars, substances)
- **Properties** (features of objects)
- **Events** (changes, processes)
- **Facts** or **states of affairs** (object-property combinations)
- **Possible worlds** (ways things could be)

Whether these categories are jointly exhaustive and mutually exclusive, and which of them are fundamental, is a matter of active debate.

## Summary

- Quine’s criterion: to be is to be the value of a bound variable; ontological commitment is determined by what a theory quantifies over
- Concrete vs abstract objects: the existence of abstract objects (numbers, properties) is contested between platonists and nominalists
- Universals vs particulars: realists, nominalists, and trope theorists disagree about whether properties are shared entities or not
- Non-existent objects: Meinongianism posits them; Russell’s theory of descriptions eliminates them
