Full Idea
We can automatically infer 'there are roses' from 'there are red roses' (with no shift in the meaning of 'roses'). Likewise one can automatically infer 'there are numbers' from 'there are prime numbers'.
Gist of Idea
If 'there are red roses' implies 'there are roses', then 'there are prime numbers' implies 'there are numbers'
Source
Jonathan Schaffer (On What Grounds What [2009], 2.1)
Book Reference
'Metametaphysics', ed/tr. Chalmers/Manley/Wasserman [OUP 2009], p.358
A Reaction
He similarly observes that the atheist's 'God is a fictional character' implies 'there are fictional characters'. Schaffer is not committing to a strong platonism with his claim - merely that the existence of numbers is hardly worth disputing.