Whatever may be the distribution of uncertainty among economists, the public only gets to hear from those who have certain opinions.

Economists are very good at saying that something cannot go on forever, but not so good at saying when it will stop.

Things that can't go on forever... don't.

If a thing can't go on forever, it will eventually stop.

Psychiatrist to patient: Maybe you don't have a complex. Maybe you are inferior.

If something is inevitable, it will happen

Trends that can't continue, won't.