In almost any decision situation, there are so many uncertainties that we need to evaluate their importance and prioritize among them. This chapter begins with a series of warnings against improper ways to do this. Most of the fallacies described consist in programmatically disregarding certain types of decision-relevant information. The types of information that can be disregarded differ between different decisions, and therefore decision rules that exclude certain types of information should not be used. The chapter proceeds by introducing a collection of useful and legitimate rules for the evaluation and prioritization of uncertainties. These rules are divided into three major groups: rules extending the scope of what we consider, rules for evaluating each uncertainty, and rules for the comparative evaluation of uncertainties (in both moral and instrumental terms). These rules should be applied in an adaptable process that allows the introduction of new and unforeseen types of arguments.