  However, this conclusion has been challenged. First of all, it has been questioned whether quantum particles can be said to possess the relevant state-dependent properties in the sense that would be damaging to PII (Massimi 2001; see also Mittelstaedt and Castellani 2000). However, this argument only applies to monadic, state-dependent properties and so the above conclusion still holds for PII(2) and PII(3). In effect, what has been shown is that those versions of PII which allow relations to individuate are not the weakest forms of the Principle, but the only forms which are applicable.