The Number of Possibilities What is the most intuitive way to quantify uncertainty? Imagine a murder has been committed. We don’t know who did it, so there’s uncertainty. If there are only two people who could have done it (Colonel Mustard and Professor Plum), the uncertainty is limited. With ten possible suspects, the uncertainty increases. If there’s only one person who could have done it, there’s no uncertainty. Thus, a straightforward measure of uncertainty would be proportional to the number of possibilities.