More importantly, I think that Maddy's objection is subtler than this formulation. The objection is directed at the motivation for P1 - not at P1 itself. Her aim is to show that confirmational holism ought to be rejected. This would rob P1 of much of its plausibility, as we shall see in the discussion following that dealing with Sober's objection. For example, 'There is a city larger than Hobart' and 'There is a natural number larger than 100' are true just in case there exist objects in the respective domains of quantification with the properties of being larger than Hobart and being larger than the natural number 100 respectively.
Most nominalists thus find themselves unable to employ such a semantics.
He thus avoids the difficult problem of providing a nominalisticlly acceptable account of the truth of such sentences. I'd like to thank Helen Regan, Angela Rosier and Ed Zalta for comments on earlier versions of this entry.