Full Idea
The Löwenheim-Skolem theorem tells us that any theory with a true interpretation has a model in the natural numbers.
Gist of Idea
Löwenheim-Skolem says any theory with a true interpretation has a model in the natural numbers
Source
Nicholas P. White (What Numbers Are [1974], V)
Book Reference
'Philosophy of Mathematics: anthology', ed/tr. Jacquette,Dale [Blackwell 2002], p.96