Some scattered thoughts (sorry for such a long comment!). Organized in order rather than by importance—I think the most important argument for me is the analogy to computers.
It’s possible to write “Humanity survives the next billion years” as a conjunction of a billion events (humanity survives year 1, and year 2, and...). It’s also possible to write “humanity goes extinct next year” as a conjunction of a billion events (Alice dies, and Bob dies, and...). Both of those are quite weak prima facie justifications for assigning high confidence. You could say that the second conjunction is different, because the billionth person is very likely to die once the others have died (since there has apparently been some kind of catastrophe), but the same is true for survival. In both cases there are conceivable events that would cause every term of the conjunction to be true, and we need to address the probability of those common causes directly. Being able to write the claim as a conjunction doesn’t seem to help you get to extreme probabilities without an argument about independence.
I feel you should be very hesitant to assign 99%+ probabilities without a good argument, and I don’t think this is about anchoring to percent. The burden of proof gets stronger and stronger as you move closer to 1, and 100 is getting to be a big number. I think this is less likely to be a tractable disagreement than the other bullets but it seems worth mentioning for completeness. I’m curious if you think there are other natural statements where the kind of heuristic you are describing (or any other similarly abstract heuristic) would justifiably get you to such high confidences. I agree with Max Daniel’s point that it doesn’t work for realistic versions of claims like “This coin will come up heads 30 times in a row.” You say that it’s not exclusive to simplified models but I think I’d be similarly skeptical of any application of this principle. (More generally, I think it’s not surprising to assign very small probabilities to complex statements based on weak evidence, but that it will happen much more rarely for simple statements. It doesn’t seem promising to get into that though.)
I think space colonization is probably possible, though getting up to probabilities like 50% for space colonization feasibility would be a much longer discussion. (I personally think >50% probability is much more reasonable than <10%.) If there is a significant probability that we colonize space, and that spreading out makes the survival of different colonists independent (as it appears it would), then it seems like we end up with some significant probability of survival. That said, I would also assign ~1/2 probability to surviving a billion years even if we were confined to Earth. I could imagine being argued down to 1⁄4 or even 1⁄8 but each successive factor of 2 seems much harder. So in some sense the disagreement isn’t really about colonization.
Stepping back, I think the key object-level questions are something like “Is there any way to build a civilization that is very stable?” and “Will people try?” It seems to me you should have a fairly high probability on “yes” to both questions. I don’t think you have to invoke super-aligned AI to justify that conclusion—it’s easy to imagine organizing society in a way which drives existing extinction risks to negligible levels, and once that’s done it’s not clear where you’d get to 90%+ probabilities for new risks emerging that are much harder to reduce. (I’m not sure which step of this you get off the boat for—is it that you can’t imagine a world that say reduced the risk of an engineered pandemic killing everyone to < 1/billion per year? Or that you think it’s very likely other much harder-to-reduce risks would emerge?)
A lot of this is about burden of proof arguments. Is the burden of proof on someone to exhibit a risk that’s very hard to reduce, or someone to argue that there exists no risk that is hard to reduce? Once we’re talking about 10% or 1% probabilities it seems clear to me that the burden of proof is on the confident person. You could try to say “The claim of ‘no bad risks’ is a conjunction over all possible risks, so it’s pretty unlikely” but I could just as well say “The claim about ‘the risk is irreducible’ is a conjunction over all possible reduction strategies, so it’s pretty unlikely” so I don’t think this gets us out of the stalemate (and the stalemate is plenty to justify uncertainty).
I do furthermore think that we can discuss concrete (kind of crazy) civilizations that are likely to have negligible levels of risk, given that e.g. (i) we have existence proofs for highly reliable machines over billion-year timescales, namely life, (ii) we have existence proofs for computers if you can build reliable machinery of any kind, (iii) it’s easy to construct programs that appear to be morally relevant but which would manifestly keep running indefinitely. We can’t get too far with this kind of concrete argument, since any particular future we can imagine is bound to be pretty unlikely. But it’s relevant to me that e.g. stable-civilization scenarios seem about as gut-level plausible to me as non-AI extinction scenarios do in the 21st century.
Consider the analogous question “Is it possible to build computers that successfully carry out trillions of operations without errors that corrupt the final result?” My understanding is that in the early 20th century this question was seriously debated (though that’s not important to my point), and it feels very similar to your question. It’s very easy for a computational error to cascade and change the final result of a computation. It’s possible to take various precautions to reduce the probability of an uncorrected error, but why think that it’s possible to reduce that risk to levels lower than 1 in a trillion, given that all observed computers have had fairly high error rates? Moreover, it seems that error rates are growing as we build bigger and bigger computers, since each element has an independent failure rate, including the machinery designed to correct errors. To really settle this we need to get into engineering details, but until you’ve gotten into those details I think it’s clearly unwise to assign very low probability to building a computer that carries out trillions of steps successfully—the space of possible designs is large and people are going to try to find one that works, so you’d need to have some good argument about why to be confident that they are going to fail.
You could say that computers are an exceptional example I’ve chosen with hindsight. But I’m left wondering if there are any valid applications of this kind of heuristic—what’s the reference class of which “highly reliable computers” are exceptional rather than typical?
If someone said:”A billion years is a long time. Any given thing that can plausibly happen should probably be expected to happen over that time period” then I’d ask about why life survived the last billion years.
You could say that “a billion years” is a really long time for human civilization (given that important changes tend to happen within decades or centuries) but not a long time for intelligent life (given that important changes takes millions of years). This is similar to what happens if you appeal to current levels of extinction risk being really high. I don’t buy this because life on earth is currently at a period of unprecedentedly rapid change. You should have some reasonable probability of returning to more historically typical timescales of hundreds of millions of years, which in turn gives you a reasonable overall probability on surviving for hundreds of millions of years. (Actually I think we should have >50% probabilities for reversion to lower timescales, since we can tell that the current period of rapid growth will soon be over. Over our history rapid change and rapid growth have basically coincided, so it’s particularly plausible that returning to slow-growth will also return to slow-change.)
Applying the rule of thumb for estimating lifetimes to “the human species” rather than “intelligent life” seems like it’s doing a huge amount of work. It might be reasonable to do the extrapolation using some mixture between these reference classes (and others), but in order to get extreme probabilities for extinction you’d need to have an extreme mixture. This is part of the general pattern why you don’t usually end up with 99% probabilities for interesting questions without real arguments—you need to not only have a way of estimating that has very high confidence, you need to be very confident in that way of estimating.
You could appeal to some similar outside view to say “humanity will undergo changes similar in magnitude to those that have occurred over the last billion years;” I think that’s way more plausible (though I still wouldn’t believe 99%) but I don’t think that it matters for claims about the expected moral value of the future.
The doomsday argument can plausibly arrive at very high confidences based on anthropic considerations (if you accept those anthropic principles with very high confidence). I think many long-termists would endorse the conclusion that the vast majority of observers like us do not actually live in a large and colonizable universe—not at 99.999999% but at least at 99%. Personally I would reject the inference that we probably don’t live in a large universe because I reject the implicit symmetry principle. At any rate, these lines of argument go in a rather different direction than the rest of your post and I don’t feel like it’s what you are getting at.
Thanks for the long comment, this gives me a much richer picture of how people might be thinking about this. On the first two bullets:
You say you aren’t anchoring, in a world where we defaulted to expressing probability in 1/10^6 units called Ms I’m just left feeling like you would write “you should be hesitant to assign 999,999M+ probabilities without a good argument. The burden of proof gets stronger and stronger as you move closer to 1, and 1,000,000 is getting to be a big number.”. So if it’s not anchoring, what calculation or intuition is leading you to specifically 99% (or at least, something in that ballpark), and would similarly lead you to roughly 990,000M with the alternate language?
My reply to Max and your first bullet both give examples of cases in the natural world where probabilities of real future events would go way outside the 0.01% − 99.99% range. Conjunctions force you to have extreme confidence somewhere, the only question is where. If I try to steelman your claim, I think I end up with an idea that we should apply our extreme confidence to the thing inside the product due to correlated cause, rather than the thing outside; does that sound fair?
The rest I see as an attempt to justify the extreme confidences inside the product, and I’ll have to think about more. The following are gut responses:
I’m not sure which step of this you get off the boat for
I’m much more baseline cynical than you seem to be about people’s willingness and ability to actually try, and try consistently, over a huge time period. To give some idea, I’d probably have assigned <50% probability to humanity surviving to the year 2150, and <10% for the year 3000, before I came across EA. Whether that’s correct or not, I don’t think its wildly unusual among people who take climate change seriously*, and yet we almost certainly aren’t doing enough to combat that as a society. This gives me little hope for dealing with <10% threats that will surely appear over the centuries, and as a result I found and continue to find the seemingly-baseline optimism of longtermist EA very jarring.
(Again, the above is a gut response as opposed to a reasoned claim.)
Applying the rule of thumb for estimating lifetimes to “the human species” rather than “intelligent life” seems like it’s doing a huge amount of work.
Yeah, Owen made a similar point, and actually I was using civilisation rather than ‘the human species’, which is 20x shorter still. I honestly hadn’t thought about intelligent life as a possible class before, and that probably is the thing from this conversation that has the most chance of changing how I think about this.
*”The survey from the Yale Program on Climate Change Communication found that 39 percent think the odds of global warming ending the human race are at least 50 percent. ”
Some scattered thoughts (sorry for such a long comment!). Organized in order rather than by importance—I think the most important argument for me is the analogy to computers.
It’s possible to write “Humanity survives the next billion years” as a conjunction of a billion events (humanity survives year 1, and year 2, and...). It’s also possible to write “humanity goes extinct next year” as a conjunction of a billion events (Alice dies, and Bob dies, and...). Both of those are quite weak prima facie justifications for assigning high confidence. You could say that the second conjunction is different, because the billionth person is very likely to die once the others have died (since there has apparently been some kind of catastrophe), but the same is true for survival. In both cases there are conceivable events that would cause every term of the conjunction to be true, and we need to address the probability of those common causes directly. Being able to write the claim as a conjunction doesn’t seem to help you get to extreme probabilities without an argument about independence.
I feel you should be very hesitant to assign 99%+ probabilities without a good argument, and I don’t think this is about anchoring to percent. The burden of proof gets stronger and stronger as you move closer to 1, and 100 is getting to be a big number. I think this is less likely to be a tractable disagreement than the other bullets but it seems worth mentioning for completeness. I’m curious if you think there are other natural statements where the kind of heuristic you are describing (or any other similarly abstract heuristic) would justifiably get you to such high confidences. I agree with Max Daniel’s point that it doesn’t work for realistic versions of claims like “This coin will come up heads 30 times in a row.” You say that it’s not exclusive to simplified models but I think I’d be similarly skeptical of any application of this principle. (More generally, I think it’s not surprising to assign very small probabilities to complex statements based on weak evidence, but that it will happen much more rarely for simple statements. It doesn’t seem promising to get into that though.)
I think space colonization is probably possible, though getting up to probabilities like 50% for space colonization feasibility would be a much longer discussion. (I personally think >50% probability is much more reasonable than <10%.) If there is a significant probability that we colonize space, and that spreading out makes the survival of different colonists independent (as it appears it would), then it seems like we end up with some significant probability of survival. That said, I would also assign ~1/2 probability to surviving a billion years even if we were confined to Earth. I could imagine being argued down to 1⁄4 or even 1⁄8 but each successive factor of 2 seems much harder. So in some sense the disagreement isn’t really about colonization.
Stepping back, I think the key object-level questions are something like “Is there any way to build a civilization that is very stable?” and “Will people try?” It seems to me you should have a fairly high probability on “yes” to both questions. I don’t think you have to invoke super-aligned AI to justify that conclusion—it’s easy to imagine organizing society in a way which drives existing extinction risks to negligible levels, and once that’s done it’s not clear where you’d get to 90%+ probabilities for new risks emerging that are much harder to reduce. (I’m not sure which step of this you get off the boat for—is it that you can’t imagine a world that say reduced the risk of an engineered pandemic killing everyone to < 1/billion per year? Or that you think it’s very likely other much harder-to-reduce risks would emerge?)
A lot of this is about burden of proof arguments. Is the burden of proof on someone to exhibit a risk that’s very hard to reduce, or someone to argue that there exists no risk that is hard to reduce? Once we’re talking about 10% or 1% probabilities it seems clear to me that the burden of proof is on the confident person. You could try to say “The claim of ‘no bad risks’ is a conjunction over all possible risks, so it’s pretty unlikely” but I could just as well say “The claim about ‘the risk is irreducible’ is a conjunction over all possible reduction strategies, so it’s pretty unlikely” so I don’t think this gets us out of the stalemate (and the stalemate is plenty to justify uncertainty).
I do furthermore think that we can discuss concrete (kind of crazy) civilizations that are likely to have negligible levels of risk, given that e.g. (i) we have existence proofs for highly reliable machines over billion-year timescales, namely life, (ii) we have existence proofs for computers if you can build reliable machinery of any kind, (iii) it’s easy to construct programs that appear to be morally relevant but which would manifestly keep running indefinitely. We can’t get too far with this kind of concrete argument, since any particular future we can imagine is bound to be pretty unlikely. But it’s relevant to me that e.g. stable-civilization scenarios seem about as gut-level plausible to me as non-AI extinction scenarios do in the 21st century.
Consider the analogous question “Is it possible to build computers that successfully carry out trillions of operations without errors that corrupt the final result?” My understanding is that in the early 20th century this question was seriously debated (though that’s not important to my point), and it feels very similar to your question. It’s very easy for a computational error to cascade and change the final result of a computation. It’s possible to take various precautions to reduce the probability of an uncorrected error, but why think that it’s possible to reduce that risk to levels lower than 1 in a trillion, given that all observed computers have had fairly high error rates? Moreover, it seems that error rates are growing as we build bigger and bigger computers, since each element has an independent failure rate, including the machinery designed to correct errors. To really settle this we need to get into engineering details, but until you’ve gotten into those details I think it’s clearly unwise to assign very low probability to building a computer that carries out trillions of steps successfully—the space of possible designs is large and people are going to try to find one that works, so you’d need to have some good argument about why to be confident that they are going to fail.
You could say that computers are an exceptional example I’ve chosen with hindsight. But I’m left wondering if there are any valid applications of this kind of heuristic—what’s the reference class of which “highly reliable computers” are exceptional rather than typical?
If someone said:”A billion years is a long time. Any given thing that can plausibly happen should probably be expected to happen over that time period” then I’d ask about why life survived the last billion years.
You could say that “a billion years” is a really long time for human civilization (given that important changes tend to happen within decades or centuries) but not a long time for intelligent life (given that important changes takes millions of years). This is similar to what happens if you appeal to current levels of extinction risk being really high. I don’t buy this because life on earth is currently at a period of unprecedentedly rapid change. You should have some reasonable probability of returning to more historically typical timescales of hundreds of millions of years, which in turn gives you a reasonable overall probability on surviving for hundreds of millions of years. (Actually I think we should have >50% probabilities for reversion to lower timescales, since we can tell that the current period of rapid growth will soon be over. Over our history rapid change and rapid growth have basically coincided, so it’s particularly plausible that returning to slow-growth will also return to slow-change.)
Applying the rule of thumb for estimating lifetimes to “the human species” rather than “intelligent life” seems like it’s doing a huge amount of work. It might be reasonable to do the extrapolation using some mixture between these reference classes (and others), but in order to get extreme probabilities for extinction you’d need to have an extreme mixture. This is part of the general pattern why you don’t usually end up with 99% probabilities for interesting questions without real arguments—you need to not only have a way of estimating that has very high confidence, you need to be very confident in that way of estimating.
You could appeal to some similar outside view to say “humanity will undergo changes similar in magnitude to those that have occurred over the last billion years;” I think that’s way more plausible (though I still wouldn’t believe 99%) but I don’t think that it matters for claims about the expected moral value of the future.
The doomsday argument can plausibly arrive at very high confidences based on anthropic considerations (if you accept those anthropic principles with very high confidence). I think many long-termists would endorse the conclusion that the vast majority of observers like us do not actually live in a large and colonizable universe—not at 99.999999% but at least at 99%. Personally I would reject the inference that we probably don’t live in a large universe because I reject the implicit symmetry principle. At any rate, these lines of argument go in a rather different direction than the rest of your post and I don’t feel like it’s what you are getting at.
Thanks for the long comment, this gives me a much richer picture of how people might be thinking about this. On the first two bullets:
You say you aren’t anchoring, in a world where we defaulted to expressing probability in 1/10^6 units called Ms I’m just left feeling like you would write “you should be hesitant to assign 999,999M+ probabilities without a good argument. The burden of proof gets stronger and stronger as you move closer to 1, and 1,000,000 is getting to be a big number.”. So if it’s not anchoring, what calculation or intuition is leading you to specifically 99% (or at least, something in that ballpark), and would similarly lead you to roughly 990,000M with the alternate language?
My reply to Max and your first bullet both give examples of cases in the natural world where probabilities of real future events would go way outside the 0.01% − 99.99% range. Conjunctions force you to have extreme confidence somewhere, the only question is where. If I try to steelman your claim, I think I end up with an idea that we should apply our extreme confidence to the thing inside the product due to correlated cause, rather than the thing outside; does that sound fair?
The rest I see as an attempt to justify the extreme confidences inside the product, and I’ll have to think about more. The following are gut responses:
I’m much more baseline cynical than you seem to be about people’s willingness and ability to actually try, and try consistently, over a huge time period. To give some idea, I’d probably have assigned <50% probability to humanity surviving to the year 2150, and <10% for the year 3000, before I came across EA. Whether that’s correct or not, I don’t think its wildly unusual among people who take climate change seriously*, and yet we almost certainly aren’t doing enough to combat that as a society. This gives me little hope for dealing with <10% threats that will surely appear over the centuries, and as a result I found and continue to find the seemingly-baseline optimism of longtermist EA very jarring.
(Again, the above is a gut response as opposed to a reasoned claim.)
Yeah, Owen made a similar point, and actually I was using civilisation rather than ‘the human species’, which is 20x shorter still. I honestly hadn’t thought about intelligent life as a possible class before, and that probably is the thing from this conversation that has the most chance of changing how I think about this.
*”The survey from the Yale Program on Climate Change Communication found that 39 percent think the odds of global warming ending the human race are at least 50 percent. ”