 Some theorists have said that life is a substance of some sort. A more plausible view is that life is a property of some sort, but we should also consider the possibility that lives are events. If we say that lives are events, we will want to know something about how to distinguish them from other events, and how they are related to the individuals that are alive. It would also be useful to know the persistence conditions for a life. If instead we conclude that life (or alive) is a property, we will want to clarify it, and identify what sorts of things bear it. Let us briefly discuss each of these views—that life is a substance, a property, or an event. 