In this chapter, it is discussed to which extent hypothetical reasoning can be modeled by formal logics. It starts by exploring this idea in general (Sects. 12.1 and 12.2), which leads to the conclusion that in order to model this kind of reasoning formally, a more fine-grained classification of reasoning patterns should be in order. After such a classification is provided in Sect. 12.3, a formal framework that has proven successful to capture some of these patterns is described (Sects. 12.4 and 12.6) and some of the specific problems for this procedure are discussed (Sect. 12.5). The chapter concludes by presenting two logics for hypothetical reasoning in an informal way (Sects. 12.7 and 12.8 ) such that the nontechnically skilled reader can get a flavor of how formal methods can be used to describe hypothetical reasoning.