He may never buy a lottery ticket, but he will buy insurance. It is a tautology to say that what is going to happen is going to happen. It is like saying that a rose is a rose. The more mysterious notion is that of something which can happen. This may be called possibility.
Possibility seems to focus on the psychological aspect of what can happen.
Suppose, for example, that a meteor is presently headed toward the city of Niagara Falls, undetected. There is nothing in the natural course of things that will impede its course. The collision with Niagara Falls, in this case, is something that will happen. In actual fact, either a non-collision or a collision is inevitable, in this case the latter. He would not be totally surprised, though certainly somewhat startled, if a collision place.