Japan will be Japan long after the United States has splintered apart due to its own internal contradictions.

The idea that GDP growth is the most important metric for the health of a society is not even wrong.

”I often think the big challenge of economics now is perhaps not managing overall growth but managing sort of "decline" overall with demographic changes.”

You are a quick thinker my friend. If you figure out how capitalism can work on a shrinking or even steady state economy you will get the Nobel price. No kidding.

Doesn't the need for continuous growth come from the interest charged on newly created money? We always have to grow to be able to afford the ever growing amount of money we owe.

With a non debt based currency, capitalism could do just fine in a shrinking economy no?

I'm not an economist by a long shot, but I would like to propose an alternative model: Whenever a bank gives out a loan, it not just creates the money that is given to the debtor. It also creates the money that will have to be paid as interest, and gives that money to the government. That could be the government's primary income stream, instead of taxes. And it guarantees that there is always enough money in the system to pay all outstanding debts.

(Looking forward to more knowledgable people pointing out the inherent flaws in this idea.)

Take some ideas from this posts:

"There is No Steady State Economy (except at a very basic level)" http://ourfiniteworld.com/2011/02/21/there-is-no-steady-stat...

Limits to Growth–At our doorstep, but not recognized http://www.resilience.org/stories/2014-02-12/limits-to-growt...

Wealth And Energy Consumption Are Inseparable http://www.declineoftheempire.com/2012/01/wealth-and-energy-...

Galactic-Scale Energy http://physics.ucsd.edu/do-the-math/2011/07/galactic-scale-e...