  Their concern with (a) followed that of many of the pioneers of structuralism in twentieth-century philosophy of science including Cassirer, Eddington and Weyl. (Russell's and Carnap's versions of structuralism were more directly motivated by epistemological and semantic problems than by ontological issues arising from physics.) French did seminal work on the identity and individuality of quantum particles with Michael Redhead (who also wrote a classic paper on theories and models (1980) and later endorsed structural realism as a way of interpreting quantum field theory (1999)). More recently it has become more widespread to advocate OSR as a response to contemporary physics as a whole (for example, see Tegmark 2007). Among others who have defended versions of OSR are Jonathan Bain (2003 and 2004), Michael Esfeld (2004) and Esfeld and Lam (2008), Aharon Kantorovich (2003), Holgar Lyre (2004), Gordon McCabe (2007) and John Stachel (2002 and 2006). Saunders and David Wallace have deployed structuralism to solve the problem of how macroscopic objects with more or less determinate properties can be recovered from the Everett interpretation of quantum states (the so-called preferred basis problem) (Saunders 1993b, 1995, and Wallace 2003). OSR is also further elaborated in Ladyman and Ross (2007) and defended against various criticisms in French and Ladyman (2011).  Quantum gravity and structuralism is discussed by an outstanding collection of philosophers and physicists in Rickles, French and Saatsi (2006).