  A rejoinder to this is the continuity argument, essentially due to Adams (1979). It is granted that almost perfect symmetry is possible. For there could be a space with nothing in it but a sequence of spheres arranged in a line at equal distance without any intrinsic difference except that one of them is scratched. The identity defence is then committed to the counter-intuitive counterfactual “If there had been no scratch on a sphere the shape of space would have been different”. 