 It is widely thought that a person has reason to satisfy her desires. On this view, for instance, if I want some ice cream, I have reason to get some. Some philosophers hold that all practical reasons are basically of this nature. The basic idea is that practical reasons are essentially facts about desire satisfaction, but there are different versions of the idea. For example, some would insist that the desires in question are not necessarily the desires that a person actually has, but are instead ones that she would have if she were fully informed and if she brought all relevant facts vividly to mind (Brandt 1979). See the entry on  reasons for action: internal vs. external.