  The combination of evidence in Dempster-Shafer theory is compared with the
combination of evidence in probabilistic logic. Sufficient conditions are
stated for these two methods to agree. It is then shown that these conditions
are minimal in the sense that disagreement can occur when any one of them is
removed. An example is given in which the traditional assumption of conditional
independence of evidence on hypotheses holds and a uniform prior is assumed,
but probabilistic logic and Dempster's rule give radically different results
for the combination of two evidence events.
