 According to one interpretation (Haenni &amp; Lehmann 2003), the number \(\Bel(A)\) represents the strength with which \(A\) is supported by the agent’s knowledge or belief base. It may well be that this base supports neither \(A\) nor its complement \(\neg A\). Since Sophia knows little about the ancient coin, her belief base will support neither the proposition \(H_a\), that it will land heads, nor the proposition \(T_a\), that it will land tails. However, Sophia may well be certain that it will not land on its edge. Hence Sophia’s DS belief function \(\Bel\) will be such that \(\Bel(H_a) = \Bel(T_a) = 0\) while \(\Bel(H_a \cup T_a) = 1\). On the other hand, Sophia is certain that the Euro coin is fair. Therefore, if \(H_e,T_e\) are the propositions that the Euro will land heads and tails respectively, her \(\Bel\) will be such that \(\Bel(H_e) = \Bel(T_e) = .5\) and \(\Bel(H_e\cup T_e) = 1\). In this way, the theory of DS belief functions can distinguish between uncertainty and ignorance about chances. Indeed,