   However concerns have been raised over the objectivity of such value state attributions (Massimi op. cit., p. 318, fn. 11) and one might regard the associated ‘empirically superfluous’ properties as merely conceptual. This bears again on the important issue of what kinds of properties may be admitted to lie within the scope of the Principle. Clearly some would appear to be beyond the pale: saving PII by regarding the particle labels themselves as intrinsic properties is surely unacceptable. Furthermore, bosons must be treated differently, since they can have the same dynamic and value states. In this case, van Fraassen suggests that each boson is individuated by its history, where this is again to be understood as ‘empirically superfluous’. Of course, it might seem odd that an approach which originally sought to avoid the grounding of the individuality of objects in something like Lockean substance should find itself having to include empirically superfluous factors within the scope of PII.