
In the
formal sciences, the domain of discourse, also called the universe of discourse,
universal set, or simply
universe, is the
set of entities over which certain
variables of interest in some
formal
Formal, formality, informal or informality imply the complying with, or not complying with, some set of requirements (forms, in Ancient Greek). They may refer to:
Dress code and events
* Formal wear, attire for formal events
* Semi-formal attire ...
treatment may range.
Overview

The domain of discourse is usually identified in the preliminaries, so that there is no need in the further treatment to specify each time the range of the relevant variables. Many logicians distinguish, sometimes only tacitly, between the ''domain of a science'' and the ''universe of discourse of a formalization of the science''.
[José Miguel Sagüillo, Domains of sciences, universe of discourse, and omega arguments, History and philosophy of logic, vol. 20 (1999), pp. 267–280.]
Examples
For example, in an
interpretation
Interpretation may refer to:
Culture
* Aesthetic interpretation, an explanation of the meaning of a work of art
* Allegorical interpretation, an approach that assumes a text should not be interpreted literally
* Dramatic Interpretation, an event ...
of
first-order logic, the domain of discourse is the set of individuals over which the
quantifiers range. A proposition such as is ambiguous, if no domain of discourse has been identified. In one interpretation, the domain of discourse could be the set of
real numbers; in another interpretation, it could be the set of
natural numbers. If the domain of discourse is the set of real numbers, the proposition is false, with as counterexample; if the domain is the set of natural numbers, the proposition is true, since 2 is not the square of any natural number.
Universe of discourse
The term "universe of discourse" generally refers to the collection of objects being discussed in a specific
discourse
Discourse is a generalization of the notion of a conversation to any form of communication. Discourse is a major topic in social theory, with work spanning fields such as sociology, anthropology, continental philosophy, and discourse analysis. ...
. In
model-theoretical semantics, a universe of discourse is the set of entities that a model is based on. The concept ''universe of discourse'' is generally attributed to
Augustus De Morgan (1846) but the name was used for the first time by
George Boole (1854) on page 42 of his ''
Laws of Thought''. Boole's definition is quoted below. The concept, probably discovered independently by Boole in 1847, played a crucial role in his philosophy of logic especially in his principle of
wholistic reference.
Boole’s 1854 definition
See also
*
Domain of a function
*
Domain theory
*
Quantifier (logic)
*
Interpretation (logic)
*
Term algebra
*
Universe (mathematics)
References
{{DEFAULTSORT:Domain Of Discourse
Semantics
Predicate logic