Personally, I feel that when your narrative about the future includes the phrase “and then a miracle happens,” you’re in trouble. - Joseph Tainter

Тhey [Romans] were forced to debase the currency. Debasing the currency for them was the same as borrowing is for us. It basically shifts the cost of solving your problems on to the future. Now, you can do that if the future doesn’t have any problems of its own. And we know that never happens, right? So the future has to deal with its own problems plus the cost of the past problems that you’ve deferred the cost of.

In talking about sustainability I like to use a metaphor of sport, of a game. When you are in a sustainability exercise it is possible to lose. You can be unsustainable. But the converse doesn't hold. There is no point at which you can say that you have won. Sustainability consists of staying in the game; that is, continuing with the ability to solve problems. It is like a dance where you must be constantly in motion. There is no point where you can rest and say "Aha! We are sustainable!" It is something that always requires adjustment.

As resources committed to benefits decline," Tainter wrote in 1988, "resources committed to control must increase.