- a quantifier indicating that the sentential function within its scope is true for all values of any variable included in the quantifier.
- a formal device indicating that the open sentence that follows is true of every member of the relevant universe of interpretation, as (∀ x)(Fx → Gx) or (x)(Fx → Gx): literally, for everything, if it is an F it is a G; that is, all Fs are Gs
