Much of the time most of us can tell whether, and which of, the sounds we are currently hearing are music. This is so whether or not what we are listening to is a familiar piece, a piece we have not heard before, or even music from a culture or tradition with which we are unfamiliar. In cases where we are unsure, or initially mistaken in our judgment, we will often change our opinion based on further information. This near-universal agreement suggests that the concept of music is one shared by different people, and has boundaries which we are implicitly aware of and which we make use of in judging whether something is music or not. The project of defining the term "music" is the attempt to make explicit the boundaries of this concept.