alternatively we do go on ad infinitum but now we are working with a quite ludicrous assumption, implying for instance, that it is infinitely more likely for the amount in envelope a to be smaller than 1, "and" infinitely more likely to be larger than 1024, than between those two values. this is a so-called improper prior distribution: probability calculus breaks down; expectation values are not even defined; see falk and konold and (1982).