 It is natural to think that if these two objects were visible, they would be visually indistinguishable. Indeed, it is tempting to think that there would be no empirical difference between o1 and o2. For those with verificationist leanings, this may lead to the belief that there is no difference at all between o1 and o2 and hence that there must be something defective about the initial set-up of the case.