Full Idea
Nominalists tend to deny the existence of abstract objects since, given their purported nature (non-causal), we can have no reason to believe in their existence.
Gist of Idea
Nominalists deny abstract objects, because we can have no reason to believe in their existence
Source
E.J. Lowe (A Survey of Metaphysics [2002], p.372)
Book Reference
Lowe,E.J.: 'A Survey of Metaphysics' [OUP 2002], p.372
A Reaction
A good point. Aristotle worried about the causal inadequacy of the Forms. My mind can conceive of a 'thing' with no causal powers, just sitting there.