 Proponents of the vera causa ideal thus oppose the idea that IBE might be something like a common methodological standard for metaphysics and for science. If metaphysicians rely on IBE to justify the entities they postulate, for examples, tropes or substances (as argued by Paul 2012), they do not hold these beliefs to the same methodological standard as scientists do (Novick forthcoming). For scientists are not content with IBE-type arguments; they require something more before they accept theoretical entities.