2 Existence and Being
Explore how ontology investigates existence and being, how entities may be grouped into categories, and why the distinction between concrete and abstract entities remains disputed.
and
asks two related questions: what exists, and what it is for anything to be at all. Asking what there is concerns reality’s inventory; asking about concerns the nature of itself. Philosophers disagree about how to answer these questions and whether and are best treated as one notion or several.
In standard first-order logic, the expresses . For example, “There is a tree” means that at least one thing is a tree. On this approach, is not an ordinary feature an object has in the way it may be red or tall.
Categories of entities
A is a broad kind of entity used to describe what exists and how different kinds of things relate. There is no single universally accepted list of categories, and philosophers disagree about which categories are fundamental or whether a shorter or different list better describes reality.
Common proposed categories include:
Objects or substances: relatively stable individuals, such as a particular tree or person.
Properties and relations: features and connections. A tree may be an object, its greenness a property, and its beside a bench a relation.
Events and processes: things that happen or unfold, such as a tree falling or a seed growing.
: often said to include numbers, sets, and propositions.
Classifying something under a proposed does not by itself prove that such things exist. Whether a has real members is a further question.
Concrete and
are typically located in space and time, or otherwise connected to the spatiotemporal world. A particular oak tree is concrete: it occupies a place, persists through time, and can affect its surroundings. are generally understood as not located in space and time in that way. The number , for example, is not found at a particular address or date, even though three apples can be.
The distinction is useful, but its exact definition and boundaries are disputed. Numbers are standard examples of ; whether properties, stories, institutions, or other less straightforward cases are abstract, concrete, or something else depends on the account. The distinction also does not settle whether exist. affirm that at least some abstract objects exist independently of our thinking about them. deny that abstract objects are needed in an account of reality, or deny that they exist.
Symbols and what they represent
A printed numeral is a concrete mark on a page, while the number it represents is commonly treated as abstract. The mark can be damaged or moved; the number is not usually thought to change when a particular inscription changes. Distinguishing the symbol from what it represents helps clarify what a theory claims exists.