I present a new argument for the thesis that there is a necessarily existing, causally powerful entity—a necessary being. The outline of the argument is this: (i) necessarily, every beginning of a certain sort S (which I'll specify) can have a cause; (ii) a beginning to the existence of all non-necessarily existing things would be of sort S; (iii) such a beginning can obtain; (iv) such a beginning cannot be caused unless there is a necessary being; therefore, (v) there is (...) a necessary being. The argument uses a causal principle that is more modest than causal principles previously used in arguments for a necessary being. (shrink)