Some things are rushing into existence, others hastening to dissolution; and of those which now exist, some parts are already flown off and vanished. The world is renewed by continual change and fluctuation, as time is by perpetual succession. Who then would set any great value on things thus floating down the stream, and of which we cannot for a moment secure the possession? One might as well love a sparrow, which flies by us and is instantly gone out of sight. Such is the life of every man; a mere vapor exhaled from the blood; a momentary breath of air, drawn in by the lungs.
Marcus Aurelius, Meditations