 In Section 5 it was discussed how the attribution of physical properties to systems in an absolute (monadic) sense leads to consistency questions. Such questions may be avoided if one adopts a metaphysics in which properties are relational. In fact, it can be argued that the mathematical structure of non-collapse quantum mechanics strongly suggests a relational picture anyhow, as evidenced, for example, by Everett’s (1957) reasons for introducing his relative states (these reasons relate to the non-collapse treatment of Wigner’s friend paradox, see also Dieks 2019, 2021).