> Exactly.
So, the bottle wasn't half full at 11:59. What was the guy's point again?
> Is that sustainable?
I don't know. I can't predict the future any more than you can. But I can tell you one thing: this is not exponential growth. Exponential curves don't have bumps. I would guess this is the superposition of multiple logistic functions.
There is one thing, though, that is sustainable for at least 4 billion years: 15 billion people who consume as much energy as Americans do today. (compare http://www-formal.stanford.edu/jmc/progress/) It doesn't look as if we'll ever reach 10 billion.
> “permanent growth” on which our politicians and economists depend on
Politicians don't, they just argue with it. Because if people demand more free stuff and lower taxes, the only way to get reelected is to argue that a much better future is just around the corner and borrow the money. That never happens, of course, but thanks to inflation, anything expressed in money looks as if did indeed grow exponentially, and everybody got their free lunch, and taxes didn't get raised, but everybody is poorer for it somehow anyway.
But Economists... I don't know why anyone ever listens to them. Nobody else can be so consistently wrong and still have such a devoted audience. When Physicists are in an argument, they run an experiment and settle it. Economists don't, they split into different schools who are all somehow right. (There's a reason why there is no Nobel Prize for Economics.)
> when will the single “bacteria” stop thinking... At 11:58 when there’s 3/4ths of the bottle still empty?
Bacteria don't think, they grow as long as they have nutrients. The exponential growth phase ends minutes into the experiment, as soon as the bacteria form a clump through which nutrients can't diffuse during one generation anymore. Minutes from the beginning of the experiment, not from the end! That's why the beginning, and only the beginning, of a logistic curve looks exponential.
Which means the bottle wasn't 1/4 filled at 11:58, it was 1/4 filled after about 1/4 of the total time. Yes, the thought experiment is this misleading, and that's exactly why Bartlett talks about it but never runs it.