Related to one aspect of this: my post Building brain-inspired AGI is infinitely easier than understanding the brain
Flying machines are one example but can we choose other examples which would teach the opposite lesson?
Nuclear Fusion Power Generation
Longs: The only way we know sustained nuclear fusion can be achieved is in stars. If we are confined to things less big than the sun then sustaining nuclear fusion to produce power will be difficult and there are many unknown unknowns.
Shorty: The key parameters are temperature and pressure and then controlling the plasma. A Tokamak design should be sufficient to achieve this - if we lose control it just means we need stronger / better magnets.
(For example, imagine a u-shaped craft with a low center of gravity and helicopter-style rotors on each tip. Add a third, smaller propeller on a turret somewhere for steering.)
Extremely minor nitpick: the low center of gravity wouldn't stabilize the craft. Helicopters are unstable regardless of where the rotors are relative to the center of gravity, due to the pendulum rocket fallacy.
Moreover, we probably won’t figure out how to make AIs that are as data-efficient as humans for a long time--decades at least.
I know you weren't endorsing this claim as definitely true, but FYI my take is that other families of learning algorithms besides deep neural networks are in fact as data-efficient as humans, particularly those related to probabilistic programming and analysis-by-synthesis, see examples here.
Planned summary for the Alignment Newsletter:
...This post argues against a particular class of arguments about AI timelines. These arguments have the form: “The brain has property X, but we don’t know how to make AIs with property X. Since it took evolution a long time to make brains with property X, we should expect it will take us a long time as well”. The reason these are not compelling is because humans often use different approaches to solve problems than evolution did, and so humans might solve the overall problem without ever needing to have property X
Great post!
we’ll either have to brute-force search for the special sauce like evolution did
I would drop the "brute-force" here (evolution is not a random/naive search).
Re the footnote:
This "How much special sauce is needed?" variable is very similar to Ajeya Cotra's variable "how much compute would lead to TAI given 2020's algorithms."
I don't see how they are similar.
Quick self-review:
Yep, I still endorse this post. I remember it fondly because it was really fun to write and read. I still marvel at how nicely the prediction worked out for me (predicting correctly before seeing the data that power/weight ratio was the key metric for forecasting when planes would be invented). My main regret is that I fell for the pendulum rocket fallacy and so picked an example that inadvertently contradicted, rather than illustrated, the point I wanted to make! I still think the point overall is solid but I do actually think this embar...
we probably won’t figure out how to make AIs that are as data-efficient as humans for a long time--decades at least. This is because 1. We’ve been trying to figure this out for decades and haven’t succeeded
EfficientZero seems to have put paid to this pretty fast. It seems incredible that the algorithmic advances involved aren't even that complex either. Kind of makes you think that people haven't really been trying all that hard over the last few decades. Worrying in terms of its implications for AGI timelines.
I like the bird-plane analogy. I kind of had the same idea, but for slightly different reason: just as man made flying machines can be superior to birds in a lot of aspects, man made ai will most likely can be superior to a human mind in a similar way.
Regarding your specific points: they may be valid, however, we do not know at which point in time we are talking about flying or AI: Probably a lot of similar arguments could have been made by Leonardo da Vinci when he was designing his flying machine; most likely he understood a lot more about birds and the ...
I think this is a good point, but I'd flag that the analogy might give the impression that intelligence is easier than it is - while animals have evolved flight multiple times by different paths (birds, insects, pterosaurs, bats) implying flight may be relatively easy, only one species has evolved intelligence.
Thanks for writing this, the power to weight statistics are quite interesting. I have an another, longer reply with my own take (edit. comments about the graph, that is) in the works, but while writing it, I started to wonder about a tangential question:
...I am saying that many common anti-short-timelines arguments are bogus. They need to do much more than just appeal to the complexity/mysteriousness/efficiency of the brain; they need to argue that some property X is both necessary for TAI and not about to be figured out for AI anytime soon, not even after th
That was an exciting graph! However, the labeling would be more consistent if it were steam engines, piston engines, and turbine engines OR stationary, ship/barge, train, automobile, and aircraft (I assume you mean airplanes and helicopters and you excluded rockets).
The wrong analogies to flight don't help much if
a) you don't know what your looking for and would need +80 OOM to "search" for a solution like evolution did (which you will never have)
b) you have no idea what intelligence is about (hint, it is NOT just about optimization, see (a)
if TAI were near I would expect
Q) more work in the field of AGI and way more AGI architectures, even with evolutionary / DL / latest clap trap hype of ML
T) more companies betting on AGI
U) a lot of strange ASI/AGI theories
V) a lot of work on RSI
W) autonomous robots roaming the...
[Epistemic status: Strong opinions lightly held, this time with a cool graph.]
I argue that an entire class of common arguments against short timelines is bogus, and provide weak evidence that anchoring to the human-brain-human-lifetime milestone is reasonable.
In a sentence, my argument is that the complexity and mysteriousness and efficiency of the human brain (compared to artificial neural nets) is almost zero evidence that building TAI will be difficult, because evolution typically makes things complex and mysterious and efficient, even when there are simple, easily understood, inefficient designs that work almost as well (or even better!) for human purposes.
In slogan form: If all we had to do to get TAI was make a simple neural net 10x the size of my brain, my brain would still look the way it does.
The case of birds & planes illustrates this point nicely. Moreover, it is also a precedent for several other short-timelines talking points, such as the human-brain-human-lifetime (HBHL) anchor.
Plan:
1909 French military plane, the Antionette VII.
By Deep silence (Mikaël Restoux) - Own work (Bourget museum, in France), CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=1615429
Illustrative Analogy
Longs: Whoa whoa, there are loads of important differences between brains and artificial neural nets: [what follows is a direct quote from the objection a friend raised when reading an early draft of this post!]
- During training, deep neural nets use some variant of backpropagation. My understanding is that the brain does something else, closer to Hebbian learning. (Though I vaguely remember at least one paper claiming that maybe the brain does something that's similar to backprop after all.)
- It's at least possible that the wiring diagram of neurons plus weights is too coarse-grained to accurately model the brain's computation, but it's all there is in deep neural nets. If we need to pay attention to glial cells, intracellular processes, different neurotransmitters etc., it's not clear how to integrate this into the deep learning paradigm.
- My impression is that several biological observations on the brain don't have a plausible analog in deep neural nets: growing new neurons (though unclear how important it is for an adult brain), "repurposing" in response to brain damage, …
Longs: Whoa whoa, there are loads of important differences between birds and flying machines:
- Birds paddle the air by flapping, whereas current machine designs use propellers and fixed wings.
- It’s at least possible that the anatomical diagram of bones, muscles, and wing surfaces is too coarse-grained to accurately model how a bird flies, but that’s all there is to current machine designs (replacing bones with struts and muscles with motors, that is). If we need to pay attention to the percolation of air through and between feathers, micro-eddies in the air sensed by the bird and instinctively responded to, etc. it’s not clear how to integrate this into the mechanical paradigm.
- My impression is that several biological observations of birds don’t have a plausible analog in machines: Growing new feathers and flesh (though unclear how important this is for adult birds), “repurposing” in response to damage ...
Shorty: The key variables seem to be size and training time. Current neural nets are tiny; the biggest one is only one-thousandth the size of the human brain. But they are rapidly getting bigger.
Once we have enough compute to train neural nets as big as the human brain for as long as a human lifetime (HBHL), it should in principle be possible for us to build HLAGI. No doubt there will be lots of details to work out, of course. But that shouldn’t take more than a few years.
Shorty: The key variables seem to be engine-power and engine weight. Current motors are not strong & light enough, but they are rapidly getting better.
Once the power-to-weight ratio of our motors surpasses the power-to-weight ratio of bird muscles, it should be in principle possible for us to build a flying machine. No doubt there will be lots of details to work out, of course. But that shouldn’t take more than a few years.
Longs: Bah! I don’t think we know what the key variables are. For example, biological brains seem to be able to learn faster, with less data, than artificial neural nets. And we don’t know why.
Besides, “there will be lots of details to work out” is a huge understatement. It took evolution billions of generations of billions of individuals to produce humans. What makes you think we’ll be able to do it quickly? It’s plausible that actually we’ll have to do it the way evolution did it, i.e. meta-learn, i.e. evolve a large population of HBHLs, over many generations. (Or, similarly, train a neural net with a big batch size and a horizon length of a lifetime).
And even if you think we’ll be able to do it substantially quicker than evolution did, it’s pretty presumptuous to think we could do it quickly enough that the HBHL milestone is relevant for forecasting.
Longs: Bah! I don’t think we know what the key variables are. For example, birds seem to be able to soar long distances without flapping their wings at all, and we still haven’t figured out how they do it. Another example: We still don’t know how birds manage to steer through the air without crashing (flight stability & control).
Besides, “there will be lots of details to work out” is a huge understatement. It took evolution billions of generations of billions of individuals to produce birds. What makes you think we’ll be able to do it quickly? It’s plausible that actually we’ll have to do it the way evolution did it, i.e. meta-design, i.e. evolve a large population of flying machines, tweaking our blueprints each generation of crashed machines to grope towards better designs.
And even if you think we’ll be able to do it substantially quicker than evolution did, it’s pretty presumptuous to think we could do it quickly enough that the date our engines achieve power/weight parity with bird muscle is relevant for forecasting.
Exciting Graph
This data shows that Shorty was entirely correct about forecasting heavier-than-air flight. (For details about the data, see appendix.) Whether Shorty will also be correct about forecasting TAI remains to be seen.
In some sense, Shorty has already made two successful predictions: I started writing this argument before having any of this data; I just had an intuition that power-to-weight is the key variable for flight and that therefore we probably got flying machines shortly after having comparable power-to-weight as bird muscle. Halfway through the first draft, I googled and confirmed that yes, the Wright Flyer’s motor was close to bird muscle in power-to-weight. Then, while writing the second draft, I hired an RA, Amogh Nanjajjar, to collect more data and build this graph. As expected, there was a trend of power-to-weight improving over time, with flight happening right around the time bird-muscle parity was reached.
I had previously heard from a friend, who read a book about the invention of flight, that the Wright brothers were the first because they (a) studied birds and learned some insights from them, and (b) did a bunch of trial and error, rapid iteration, etc. (e.g. in wind tunnels). The story I heard was all about the importance of insight and experimentation--but this graph seems to show that the key constraint was engine power-to-weight. Insight and experimentation were important for determining who invented flight, but not for determining which decade flight was invented in.
Analysis
Part 1: Extra brute force can make the problem a lot easier
One way in which compute can substitute for insights/algorithms/architectures/ideas is that you can use compute to search for them. But there is a different and arguably more important way in which compute can substitute for insights/etc.: Scaling up the key variables, so that the problem becomes easier, so that fewer insights/etc. are needed.
For example, with flight, the problem becomes easier the more power/weight ratio your motors have. Even if the Wright brothers didn’t exist and nobody else had their insights, eventually we would have achieved powered flight anyway, because when our engines are 100x more powerful for the same weight, we can use extremely simple, inefficient designs. (For example, imagine a u-shaped craft with a low center of gravity and helicopter-style rotors on each tip. Add a third, smaller propeller on a turret somewhere for steering. EDIT: Oops, lol, I'm actually wrong about this. Keeping center of gravity low doesn't help. Welp, this is embarrassing.)
With neural nets, we have plenty of evidence now that bigger = better, with theory to back it up. Suppose the problem of making human-level AGI with HBHL levels of compute is really difficult. OK, 10x the parameter count and 10x the training time and try again. Still too hard? Repeat.
Note that I’m not saying that if you take a particular design that doesn’t work, and make it bigger, it’ll start working. (If you took Da Vinci’s flying machine and made the engine 100x more powerful, it would not work). Rather, I’m saying that the problem of finding a design that works gets qualitatively easier the more parameters and training time you have to work with.
Finally, remember that human-level AGI is not the only kind of TAI. Sufficiently powerful R&D tools would work, as would sufficiently powerful persuasion tools, as might something that is agenty and inferior to humans in some ways but vastly superior in others.
Part 2: Evolution produces complex mysterious efficient designs by default, even when simple inefficient designs work just fine for human purposes.
Suppose that actually all we have to do to get TAI is something fairly simple and obvious, but with a neural net 10x the size of my (actual) brain and trained for 10x longer. In this world, does the human brain look any different than it does in the actual world?
No. Here is a nonexhaustive list of reasons why evolution would evolve human brains to look like they do, with all their complexity and mysteriousness and efficiency, even if the same capability levels could be reached with 10x more neurons and a very simple architecture. Feel free to skip ahead if you think this is obvious.
Part 3: What’s bogus and what’s not
The general pattern of argument I think is bogus is:
As argued above, if TAI is near, there should still be many X which are important to how the brain functions, which we don’t know how to reproduce in AI, and which it took evolution a long time to produce. So rattling off a bunch of X’s is basically zero evidence against TAI being near.
Put differently, here are two objections any particular argument of this type needs to overcome:
This reveals how the arguments could be reformulated to become non-bogus! They need to argue (a) that X is probably necessary for TAI, and (b) that X isn’t something that we’ll figure out fairly quickly once the key variables of size and training time are surpassed.
In some cases there are decent arguments to be made for both (a) and (b). I think efficiency is one of them, so I’ll use that as my example below.
Part 4: Example: Data-efficiency
Let’s work through the example of data-efficiency. A bad version of this argument would be:
The rebuttal to this bad argument is:
However, I do think the argument can be reformulated and expanded to become good. Here’s a sketch, inspired by Ajeya Cotra’s argument here.
I think this is a good argument. Do I buy it? Not yet. For one thing, I haven’t verified whether the claims it makes are true, I just made them up as plausible claims which would be persuasive to me if true. For another, some of the claims actually seem false to me. Finally, I suspect that in 1895 someone could have made a similarly plausible argument about energy efficiency, and another similarly plausible argument about flight control, and both arguments would have been wrong: Energy efficiency turned out to be insufficiently necessary, and flight control turned out to be insufficiently difficult!
Conclusion
What I am not saying: I am not saying that the case of birds and planes is strong evidence that TAI will happen once we hit the HBHL milestone. I do think it is evidence, but it is weak evidence. (For my all-things-considered view of how many orders of magnitude of compute it’ll take to get TAI, see future posts, or ask me.) I would like to see a more thorough investigation of cases in which humans attempt to design something that has an obvious biological analogue. It would be interesting to see if the case of flight was typical. Flight being typical would be strong evidence for short timelines, I think.
What I am saying: I am saying that many common anti-short-timelines arguments are bogus. They need to do much more than just appeal to the complexity/mysteriousness/efficiency of the brain; they need to argue that some property X is both necessary for TAI and not about to be figured out for AI anytime soon, not even after the HBHL milestone is passed by several orders of magnitude.
Why this matters: In my opinion the biggest source of uncertainty about AI timelines has to do with how much “special sauce” is necessary for making transformative AI. As jylin04 puts it,
In my words: Evolution clearly put lots of special sauce into humans, and took millions of generations of millions of individuals to do so. How much special sauce will we need to get TAI?
Shorty is one end of a spectrum of disagreement on this question. Shorty thinks the amount of special sauce required is small enough that we’ll “work out the details” within a few years of having the key variables (size and training time). At the other end of the spectrum would be someone who thought that the amount of special sauce required is similar to the amount found in the brain. Longs is in the middle. Longs thinks the amount of special sauce required is large enough that the HBHL milestone isn’t particularly relevant to timelines; we’ll either have to brute-force search for the special sauce like evolution did, or have some brilliant new insights, or mimic the brain, etc.
This post rebutted common arguments against Shorty’s position. It also presented weak evidence in favor of Shorty’s position: the precedent of birds and planes. In future posts I’ll say more about what I think the probability distribution over amount-of-special-sauce-needed should be and why.
Acknowedgements: Thanks to my RA, Amogh Nanjajjar, for compiling the data and building the graph. Thanks to Kaj Sotala, Max Daniel, Lukas Gloor, and Carl Shulman for comments on drafts. This research was conducted at the Center on Long-Term Risk and the Polaris Research Institute.
Appendix
Some footnotes:
Some bookkeeping details about the data: