 If we understand the notion of mind-dependence in this way, it is a mistake to insist that abstract objects be mind-independent. To strike a theme that will recur, it is widely supposed that sets and classes are abstract entities—even the impure sets whose urelements are concrete objects. Any account of the abstract/concrete distinction that places set-theoretic constructions like \(\{\textrm{Alfred}, \{\textrm{Betty}, \{\textrm{Charlie}, \textrm{Deborah}\}\}\}\) on the concrete side of the line will be seriously at odds with standard usage. With this in mind, consider the set whose sole members are X’s afterimage and Y’s headache, or some more complex set-theoretic object based on these items. If we suppose, as is plausible, that an impure set exists at a time only when its members exist at that time, this will be a mind-dependent entity in the generous sense. But it is also presumably an abstract entity.