  Alternatively, but relatedly, non-individuality can be understood in terms of the denial of self-identity. This suggestion can be found most prominently in the philosophical reflections of Born, Schrödinger, Hesse and Post (Born 1943; Schrödinger 1952; Hesse 1963; Post 1963). It is immediately and clearly problematic, however: how can we have objects that are not identical to themselves? Such self-identity seems bound up with the very notion of objecthood in the sense that it is an essential part of what it is to be that object (thus it has been suggested that non-individuality might be better understood in terms of the loss of patio-temporal trajectories in quantum physics; see Arenhart, Bueno and Krause 2019). This intuition is summed up in the Quinean slogan, ‘no entity without identity’ (Quine 1969), with all its attendant consequences regarding reference etc.