 The second motivation for imprecise probability is that even if all the relevant probabilities are subjective, a decision-maker’s betting behavior might depend on how reliable or well-supported by evidence those probabilities are. Consider a decision-maker who may bet on three different tennis matches: in the first, she knows a lot about the players and knows they are very evenly matched; in the second, she knows nothing whatsoever about either player; and in the third, she knows that one of the two players is much better than the other, but she does not know which one. In each of the matches, the decision-maker should presumably assign equal probability to each player winning, since her information in favor of each is symmetrical; nonetheless, it seems rational to bet only on the first match and not on the other two (Gärdenfors &amp; Sahlin 1982; see also Ellsberg 1961).