No Short Em Age

The basic premise of my book is that the next big revolution on the scale of the farming and industrial revolutions will come from human level artificial intelligence in the form of brain emulations (ems). Yes, because people have asked I’ve estimated that this will happen within roughly a century, but that estimate isn’t central. The key is that even if ems take many centuries, they will still come before achieving human level artificial intelligence via the usual methods (UAI – via hand-coded algorithms including statistics), and before other social disruptions of this magnitude.

I’ve argued that this premise is plausible because it is hard to imagine social disruptions as big as AI, and because at past rates of progress UAI should take centuries, while ems look like they’ll be ready sooner. Yes, some people are so impressed by recent UAI demos that they think this time is different, so that we will now see an unprecedented burst of progress all the way to full UAI within a decade or two. But I remember past demos that were similarly impressive relative to then-current abilities.

Some people think the basic premise of my book is too weird, while others see it as not weird enough. This post addresses the most common objection I’ve heard from this second group: that even if ems come first, the usual AI will appear a few hours later, making the age of em too short to be worth much consideration.

Now there is certainly one way big ems make full UAI come faster: by speeding up overall economic growth. I’ve suggested the em economy might double every month or faster, and while some doubt this, few who think my book not weird enough are among them.

Since the economy mainly grows today via innovation, our ladder of growth is basically a ladder of overall innovation. We only double the economy when we have on averaged doubled our abilities across all economic sectors. So if the relative rates of economic growth and innovation in different sectors stay the same, then speeding up economic growth means speeding up the rate of progress toward full UAI. (While some expect a larger economy to innovate faster because it has more resources, the steady economic growth rates we’ve seen suggest there are contrary forces, such as picking the low hanging fruit of research first.)

For example, at past rates of UAI progress it should take two to four centuries to reach human level abilities in the typical UAI subfield, and thus even longer in most subfields. Since the world economy now doubles roughly every fifteen years, that comes to twenty doublings in three centuries. If ems show up halfway from now to full human level usual AI, there’d still be ten economic doublings to go, which would then take ten months if the economy doubled monthly. Which is definitely faster UAI progress.

However, ten doublings of the economy can encompass a whole era worthy of study. I’ve argued that ems would typically run fast enough to fit a subjective career of a century or more within an economic doubling time, so that their early career training can remain relevant over a whole career. So ten doublings is at least ten subjective centuries, which is plenty of time for lots of cultural and social change. A whole age of change, in fact.

Some argue that the existence of ems would speed up innovation in general, because ems are smarter and innovation benefits more from smarts than does typical production. But even if true, this doesn’t change the relative rate of innovation in UAI relative to other areas.

Some argue that ems speed up UAI progress in particular, via being able to inspect brain circuits in detail and experiment with variations. But as it can be very hard to learn how to code just from inspecting object spaghetti code from other coders, I’m skeptical that this effect could speed up progress anything like a factor of two, which would be where two (logarithmic) steps on the UAI ladder of progress are now jumped when single steps are on average jumped elsewhere. And even then there’d still be at least five economic doublings in the em era, giving at least five subjective centuries of cultural change.

And we know of substantial contrary effects. First, UAI progress seems driven in part by computer hardware progress, which looks like it will be slower in the coming decades than it has in past decades, relative to other areas of innovation. More important, a big part of em era growth can be due to raw physical growth in production, via making many more ems. If half of em economic growth is due to this process then the em economy makes two (logarithmic) steps of economic growth for every step on the ladder of innovation progress, turning ten ladder steps into twenty doublings. A long age of em.

Some argue that the availability of ems will greatly speed the rate of UAI innovation relative to other rates of innovation. They say things like:

When ems are cheap, you could have a million top (e.g., 100 times average) quality UAI research ems each running at a million times human speed. Since until now we’ve only had a thousand average quality UAI researchers at any one time, UAI progress could be a hundred billion times faster, making what would have taken three centuries now take a tenth of a second. The prize of getting to full UAI first would induce this investment.

There are just so many things wrong with this statement.

First, even if human speed ems are cheap, mega-ems cost at least a million times as much. A million mega-ems are as productive as trillion humans, times whatever factor by which the typical human-speed em is more productive than a typical human. The em economy would have to have grown a whole lot before it is even possible to devote that level of resources to UAI research. So there can be a whole em era before that point.

Second, this same approach seems equally able to speed up progress in any innovation area that isn’t strongly limited by physical process rates. Areas that only moderately depend on physical rates can spend more to compensate, so that their innovation rates slow only modestly. If only a modest fraction of innovation areas were substantially limited by physical rates, that would only speed up UAI progress by a modest factor relative to overall economic growth.

Third, just because some researchers publish many more academic papers than others doesn’t at all mean that young copies of those researchers assigned to other research areas would have published similarly. Ex ante expected researcher quality varies a lot less than ex post observed research publications. Yes, people often vary by larger factors in their ability to do pure math, relative to other abilities, but pure math contributes only a small fraction to overall innovation.

Fourth, it is well known that most innovation doesn’t come from formal research, and that innovations in different areas help each other. Economists have strong general reasons to expect diminishing returns to useful innovation from adding more researchers. Yes, if you double the number of researchers in one area you’ll probably get twice as many research papers in that area, but that is very different from twice as getting much useful progress.

As I mention in my book, in some cases we’ve actually measured how research progress varies with the number of researchers, and it looks more like a square root dependence. In addition, if innovation rates were linear in the number of formal researchers, then given the tiny fraction of such researchers today we’d have to be vastly underinvesting in them, and so nations who invest more in formal research should expect to see much higher rates of economic growth. Yet we don’t actually see much of a relation between economic growth and spending on formal research. (Yes studies vary, so there could be a modest, but not a huge, effect.)

So, in sum, we should expect that useful UAI innovation doesn’t mostly come from formal research, and so doubling the number of UAI researchers, or doubling their speed, doesn’t remotely double useful innovation. We aren’t vastly underinvesting in formal research, and so future parties can’t expect to achieve huge gains by making a huge new investment there. We can expect to see modest gain in UAI innovation, relative to today and to other innovation areas, from an ability to inspect and experiment with ems, and from not being very limited by physical process rates. But these give less than a factor of two, and we should see a factor of two in the other direction from slowing hardware gains and from innovation mattering less for economic growth.

Thus we should expect many doublings of the em era after ems and before human level UAI, resulting in many centuries of subjective cultural change for typical ems. Giving an em era that is long enough to be worth considering. If you want to study whatever comes after the em era, understanding the em era should help.