Nature has an aim in all things, in the end and surcease of them no less than in their beginning and continuance. It is even as a man casting a ball. Where, then, is the good for the ball in its rising; where the harm in dropping; where even is the harm when it has fallen down? Where is the bubble's good while it holds together, where is the evil when it is broken? So it is with the lamp which now burns and anon goes out.