 Lewis (1986b) gives a different fine-grained theory of events. On Lewis’s view, events are properties of a spacetime region. For Lewis, properties are intensions, or classes of possible individuals. So, on Lewis’s view, events are classes of spacetime regions at possible worlds. What it is for an event to occur at a world, w, is for the event to contain a spacetime region from w. Lewis is also able to distinguish the ball’s rotation from its heating; though these events occupy the same region of spacetime at the actual world, they do not necessarily co-occur. It is possible for the ball to heat without rotating, and it is possible for the ball to rotate without heating. So the class of spacetime regions in which the ball rotates is not the same as the class of spacetime regions in which the ball heats, and if Lewis identifies the former class with the event of the ball rotating, and the latter with the event of the ball heating, then he may distinguish these two events.