There are some cases where using the extreme minimalism of doesn’t prevent one from constructing acceptable models. For instance, if the possible states that the observer in Incubator may end up in upon discovering that he has a black beard (i.e. or ) are subjectively indistinguishable then replicates the reference class partition that we used above and will thus yield the same credence assignment.
doesn’t prevent one from constructing acceptable models. 
or 
) are subjectively indistinguishable then