I don't agree that slave use dooms civilisation. In fact it's a very practical, if ethically unsupportable, answer to the energy crisis. Slave-based civilisation seem to do just fine - it's usually some external crisis or unchecked internal greed that kills them.
It's possible to imagine a weird quasi-Athenian slave-based 'democracy' that can provide replacement energy once we run out of fossil fuels. I wouldn't be surprised if that's where we end up, collectively.
Which suggest the real problem isn't energy economy, it's psychology and politics - specifically how do you create a political environment that goes beyond Marxists vs Capitalists and values long-sighted sane decisions than short-sighted insane ones?
I have seen the argument presented as a simple accounting metaphor for the amount of human/animal energy equivalent of fossil fuel use, without the moral overtones. Can the last politician to go out the revolving door please turn the lights off?
