The impure relative identity trinitarian owes us a plausible and orthodox metaphysical story about how non-identical beings may nonetheless be 'one God'.

Michael Rea (2003) objects that by remaining neutral on the issue of identity, van Inwagen’s theory allows that the three Persons are (absolutely) non-identical, in which case “it is hard to see what it could possibly mean to say that they are the same being” (Rea 2003, 441). It seems that any things which are non-identical are not the same being. Thus, van Inwagen must assume that there is absolute identity, and deny that this relation holds between the Persons. Thus, van Inwagen has not demonstrated the consistency of (this version of) trinitarianism. Further, the theory doesn’t rule out pol...