[chrispenycate]

I suspect you underestimate the human penchant for creating labels.
Even without a personal name, in order to think of him we will automatically generate a label for someone, "Boy", "slave" even "you there", a generic label for all those in his particular situation, perhaps (indistiguishable between themselves, any slave being equivalent to any other) but without at least a functional label, we're not equipped to cogitate (hardly even to recognise)
The problem here is that different humans could well apply different labels.