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Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Things usually end slowly, published by OllieBase on June 7, 2022 on The Effective Altruism Forum. Epistemic status: Low confidence. These findings updated me slightly towards worrying more about slow declines vs. sudden collapse/extinction. Most sources are things I quickly googled so are probably off the mark. TL;DR It’s sometimes claimed or suggested that if an extinction event were to happen, it would happen very quickly (i.e. days, weeks, months). However, when empires fall or species go extinct, they usually do so very slowly (years, decades, millennia). These base rates suggest we should have a reasonably strong prior on slow decline when thinking about civilisational collapse and, at more of a stretch, existential risks. This sketch is very rough, and I’d love to see someone work out these base rates, and how they might be changing, more carefully. Rapid extinction Thinkers in and around the EA community sometimes claim that x-risk scenarios will cause extinction rapidly. For example: Eliezer Yudkowsky argues that the likely scenario with AGI takeoff is “growth stays at 5%/year and then everybody falls over dead in 3 seconds and the world gets transformed into paperclips” Toby Ord, in The Precipice (p.28), writes that “As technology continues to advance, new threats appear on the horizon. These threats promise to be more like nuclear weapons than like climate change: resulting from sudden breakthroughs, precipitous catastrophes” Relatedly, the metaphor of a precipice implies a very steep descent from stability to extinction. Perhaps it’s right to expect that an existential catastrophe will be rapid. Your inside view might well take into account things happening awfully fast (such as rapidly increasing compute efficiency or pathogens spreading). But holding this view should require a very strong update from the prior that extinction events and civilisational collapses usually take a very long time. Data from civilisations Two caveats: I expect the way I’m most likely to be wrong about all this is that historical extinctions and civilisational collapses are not appropriate reference classes for x-risks. I think they’re very useful because they’re a rough approximation of x-risks from actual data and I’m sceptical of claims along the lines of “the thing I’m worried about is totally unique ”, but I could be wrong. While we often refer to the “fall” of Rome and the “collapse” of the Mayans, it’s rarely appropriate to consider human empires and civilisations extinct. In this post, I usually use years when the empire or civilisation is considered by scholars to have “ended.” The specific year, or whether they “ended” at all, is usually up for debate. To form a rough prior on how long things (civilisations, empires, species) take to decline, I scanned some encyclopedic pages to find: The start of the end: the last period in time when the civilisation was still ‘flourishing’, usually just before the start of a collapse or invasion. The earliest plausible date and the latest plausible date which could constitute the “end” of the civilization, to form a kind of confidence interval. This sheet lists some empires, their last points of flourishing, their earliest reasonable dissolution points and their latest reasonable dissolution points. From this, I calculated a lower guess on decline length and an upper guess on decline length (in years). You can see this summary graph below. I expect anyone could review these dates and find points of disagreement, even by reviewing the same sources I did. Furthermore, I’d love to see someone expand this list (perhaps using this useful list compiled by Luke Kemp). You don’t need to read this data too carefully to notice that rapid dissolution is clearly the exception to the rule. One interesting thing to note, however, is that declines...