Right, if you cannot compare utilities, you are safe from the repugnant conclusion.
On the other hand, this is not very useful instrumentally, as a functioning society necessarily requires arbitration of individual wants. Thus some utilities must be comparable, even if others might not be. Finding a boundary between the two runs into the standard problem of two nearly identical preferences being qualitatively different.
Right, if you cannot compare utilities, you are safe from the repugnant conclusion.
On the other hand, this is not very useful instrumentally, as a functioning society necessarily requires arbitration of individual wants. Thus some utilities must be comparable, even if others might not be. Finding a boundary between the two runs into the standard problem of two nearly identical preferences being qualitatively different.