  This conclusion – that quantal objects are not individuals – is not the whole story, however. First of all, the contrast between classical and quantum physics with regard to individuality and non-individuality is not as straightforward as it might seem. As already indicated, the above account involving permutations of particles in boxes appears to fit nicely with an understanding of individuality in terms of Lockean substance or primitive thisness. However, one can give an alternative field-theoretic account in which particles are represented as dichotomic ‘Yes/No’ fields: with such a field, the field amplitude is simply ‘Yes’ at location x if the ‘particle’ is present at x and ‘No’ if it is not (Redhead 1983). On this account, individuality is conferred via spatio-temporal location together with the assumption of impenetrability mentioned in the Introduction. Thus the above account of particle individuality in terms of either Lockean substance or primitive thisness is not necessary for classical statistical mechanics. 