What does Robin Hanson think is the most likely “Great Filter”?

Here is a long and excellent post, whereby Robin outs himself as a strange kind of environmentalist.  Do need the whole thing, but here is one summary excerpt:

So, bottom line, the future great filter scenario that most concerns me is one where our solar-system-bound descendants have killed most of nature, can’t yet colonize other stars, are general predators and prey of each other, and have fallen into a short-term-predatory-focus equilibrium where predators can easily see and travel to most all prey. Yes there are about a hundred billion comets way out there circling the sun, but even that seems a small enough number for predators to careful map and track all of them.

“At first they came for the rabbits…and then they came for me.”  I find that intriguing, but I have a more marginalist approach, and perhaps one which encompasses Robin’s hypothesis as a special case.  The death of human (and other) civilizations may be a bit like the death of the human body through old age, namely a whole bunch of things go wrong at once.  If there were a single key problem, it would be easier to find a patch and prolong things for just a bit more.  But if we have reason to believe that, eventually, many things will go wrong at once…such a concatenation of problems is more likely to defeat us.  So my nomination for The Great Filter, in a nutshell, is “everything going wrong at once.”  The simplest underlying model here is that a) problems accumulate, b) resources can be directed to help solve problems, and c) sometimes problems accumulate more rapidly than they can be solved.

This is also why, in many cases, there is no simple “fact of the matter” answer as to why various mighty empires fell in the past.  Here is my earlier review of Apocalypto, a remarkable and still underrated movie.