Editing Axiom schema of specification (section)

== In higher-order settings ==
{{Unreferenced section|date=June 2024}}
In a [[type theory|typed]] language where we can quantify over predicates, the axiom schema of specification becomes a simple axiom. This is much the same trick as was used in the NBG axioms of the previous section, where the predicate was replaced by a class that was then quantified over.

In [[second-order logic]] and [[higher-order logic]] with higher-order semantics, the axiom of specification is a logical validity and does not need to be explicitly included in a theory.