In predicate logic, universal instantiation[1][2][3] (UI; also called universal specification or universal elimination,[citation needed] and sometimes confused with dictum de omni)[citation needed] is a valid rule of inference from a truth about each member of a class of individuals to the truth about a particular individual of that class.

It is generally given as a quantification rule for the universal quantifier but it can also be encoded in an axiom schema.

Formally, the rule as an axiom schema is given as for every formula A and every term t, where

And as a rule of inference it is Irving Copi noted that universal instantiation "...follows from variants of rules for 'natural deduction', which were devised independently by Gerhard Gentzen and Stanisław Jaśkowski in 1934.

The principle embodied in these two operations is the link between quantifications and the singular statements that are related to them as instances.