  Indifference realism is not a complete departure from material essence realism because William still accepts accidental individuation. When the accidents are stripped away, Plato and Socrates are still one and the same although in the weaker sense of ‘one’ and ‘same’. They do not share a material essence, though they each have the same state or status of being a man.  William's indifference realism holds that when individuating accidents are stripped away from two individuals, what you are left with may be numerically distinct but it is not individually discernible (you can't tell which one is Socrates). What is left then are pure things—there are no individuating characteristics. In this sense, each thing is itself a universal.