In this article, we develop an inventory of the explananda that any complete theory of humor should account for. In the first chapter, we argue that humor is a property of events in the mind, rather than objects in the world (such as jokes), and we point out that a result of this is that individual jokes are not universal. We also suggest that while some varieties of laughter may be triggered by situations that are not humorous in any sense, a special connection exists between Duchenne-type laughter and the certain type of cognitive stimulation that usually elicits it. Then we argue that the feeling of mirth - perhaps the most central aspect of humor - is a psychological phenomena that should be explored by means of a "heterophenomenological" approach - one that uses subjective states as data to be explained, but not necessarily as valid interpretations of the underlying psychological phenomena. And we comment that this feeling ("funny" - humorous) is closely related to another feeling: "funny" - odd - a relationship worth exploring in any theory of humor. In the second chapter, we catalogue the findings of these explorations and others, in addition to those further explananda highlighted by previous theories of humor.