  Furthermore, even if we accept the methodological principle of ‘the less surplus structure the better’, it is not clear that QFT understood in terms of non-individual ‘quanta’ offers any significant advantage in this respect (although see da Costa and Holik 2015 for an account in these terms of states with undefined particle number, characteristic of QFT). Indeed, it has been argued that the formalism of QFT is also compatible with the alternative package of objects as individuals. Van Fraassen has pressed this claim (1991), drawing on de Muynck’s construction of state spaces for QFT which involve labelled particles (1975). Butterfield, however, has argued that the existence of states that are superpositions of particle number, within QFT, undermines the equivalence (1993). Nevertheless, Huggett insists, in this case the undermining is empirical, rather than methodological (Huggett 1995).  When the number is constant, it is the states for arbitrary numbers of particles which are so much surplus structure and now, if the methodological argument is applied, it is the individuals package which is to be preferred.