Billy Brown summarized:
> 1) A future in which lifespans become very long (>200 years).
> 2) At least reasonably good (by current standards) economic conditions.
> 3) A population in which a majority of people over age 50 wish to retire.
Let's not get so caught up in compound interest rates that we forget the underlying manufacture and distribution of "stuff". The real question is the teenagers who are actually working will be productive enough, thanks to ever-increasing technology, to support all the old fogies.
Actually, I expect that once the economy gets up to that stage, most people will invest their weekly allowances so they don't have to work as teenagers either. One of two things will happen; either you'll get a permanent class of poor workers kept poor by some huge number of regulations, or the work will be done by people who enjoy it, or the economy will strike a balance at the point where labor is so valuable that people come out of retirement once a year to work for a few hours and buy themselves a mansion.
-- email@example.com Eliezer S. Yudkowsky http://pobox.com/~sentience/AI_design.temp.html http://pobox.com/~sentience/singul_arity.html Disclaimer: Unless otherwise specified, I'm not telling you everything I think I know.