In
metaphysics, the distinction between abstract and concrete refers to a divide between two types of entities. Many philosophers hold that this difference has fundamental metaphysical significance. Examples of concrete objects include
plants,
human beings and
planets while things like
numbers,
sets and
propositions are abstract objects.
There is no general
consensus as to what the characteristic marks of concreteness and abstractness are. Popular suggestions include defining the distinction in terms of the difference between (1) existence inside or outside space-time, (2) having causes and effects or not, (3) having contingent or necessary existence, (4) being particular or universal and (5) belonging to either the physical or the mental realm or to neither.
Despite this diversity of views, there is broad agreement concerning most objects as to whether they are abstract or concrete.
So under most interpretations, all these views would agree that, for example, plants are concrete objects while numbers are abstract objects.
Abstract objects are most commonly used in
philosophy
Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. Some ...
and
semantics. They are sometimes called ''abstracta'' in contrast to ''
concreta''. The term ''abstract object'' is said to have been coined by
Willard Van Orman Quine.
Abstract object theory is a discipline that studies the nature and role of abstract objects. It holds that properties can be related to objects in two ways: through exemplification and through encoding. Concrete objects exemplify their properties while abstract objects merely encode them. This approach is also known as the
dual copula strategy.
In philosophy
The
type–token distinction identifies physical objects that are tokens of a particular type of thing. The "type" of which it is a part is in itself an abstract object. The abstract–concrete distinction is often introduced and initially understood in terms of paradigmatic examples of objects of each kind:
Abstract objects have often garnered the interest of philosophers because they raise problems for popular theories. In