Full Idea
Axiom of Existence: there exists at least one set. This may be the empty set, but you need to start with something.
Gist of Idea
Axiom of Existence: there exists at least one set
Source
Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15)
Book Reference
Clegg,Brian: 'Infinity' [Robinson 2003], p.205