Hacker News Reader

Comment by ancillary | Hacker News Reader

I'm not OP or a doomer, but I do worry about AI making tasks too achievable. Right now if a very angry but not particularly diligent or smart person wants to construct a small nuclear bomb and detonate it in a city center, there are so many obstacles to figuring out how to build it that they'll just give up, even though at least one book has been written (in the early 70s! The Curve of Binding Energy) arguing that it is doable by one or a very small group of committed people.

Given an (at this point still hypothetical, I think) AI that can accurately synthesize publicly available information without even needing to develop new ideas, and then break the whole process into discrete and simple steps, I think that protective friction is a lot less protective. And this argument applies to malware, spam, bioweapons, anything nasty that has so far required a fair amount of acquirable knowledge to do effectively.

View on HN

I get your point, but even whole ass countries routinely fail at developing nukes.

"Just" enrichment is so complicated and requires basically every tech and manufacturing knowledge humanity has created up until the mid 20th century that an evil idiot would be much better off with just a bunch of fireworks.

It might require that knowledge implicitly, in the tools and parts the evil idiot would use, but they presumably would procure these tools and parts, not invent or even manufacture them themselves.

Even that is insanely difficult. There's a great book by Michael Levi called On Nuclear Terrorism, which never got any PR because it is the anti-doomer book.

He methodically goes through all the problems that an ISIS or a Bin Laden would face getting their hands on a nuke or trying to manufacture one, and you can see why none of them have succeeded and why it isn't likely any of them would.

They are incredibly difficult to make, manufacture or use.

It's very convenient that it is that hard.

Yeah, the interview with Geoffrey Hinton had a much better summary of risks. If we're talking about the bad actor model, biological weaponry is both easier to make and more likely as a threat vector than nuclear.

Biological weapons are probably the more worrisome case for AI. The equipment is less exotic than for nuclear weapon development, and more obtainable by everyday people.

Knowing how is very rarely the relevant obstacle. In the case of nuclear bombs the obstacles are, in order of easiest to hardest:

1. finding out how to build one

2. actually building the bomb once you have all the parts

3. obtaining (or building) the equipment needed to build it

4. obtaining the necessary quantity of fissionable material

5. not getting caught while doing 3 & 4

A couple of bright physics grad students could build a nuclear weapon. Indeed, the US Government actually tested this back in the 1960s - they had a few freshly minted physics PhDs design a fission weapon with no exposure to anything but the open literature [1]. Their design was analyzed by nuclear scientists with the DoE, and they determined it would most likely work if they built and fired it.

And this was in the mid 1960s, where the participants had to trawl through paper journals in the university library and perform their calculations with slide rules. These days, with the sum total of human knowledge at one's fingertips, multiphysics simulation, and open source Monte Carlo neutronics solvers? Even more straightforward. It would not shock me if you were to repeat the experiment today, the participants would come out with a workable two-stage design.

The difficult part of building a nuclear weapon is and has always been acquiring weapons grade fissile material.

If you go the uranium route, you need a very large centrifuge complex with many stages to get to weapons grade - far more than you need for reactor grade, which makes it hard to have plausible deniability that your program is just for peaceful civilian purposes.

If you go the plutonium route, you need a nuclear reactor with on-line refueling capability so you can control the Pu-239/240 ratio. The vast majority of civilian reactors cannot be refueled online, with the few exceptions (eg: CANDU) being under very tight surveillance by the IAEA to avoid this exact issue.

The most covert path to weapons grade nuclear material is probably a small graphite or heavy water moderated reactor running on natural uranium paired up with a small reprocessing plant to extract the plutonium from the fuel. The ultra pure graphite and heavy water are both surveilled, so you would probably also need to produce those yourself. But we are talking nation-state or megalomaniac billionaire level sophistication here, not "disgruntled guy in his garage." And even then, it's a big enough project that it will be very hard to conceal from intelligence services.

[1] https://en.wikipedia.org/wiki/Nth_Country_Experiment

> The difficult part of building a nuclear weapon is and has always been acquiring weapons grade fissile material.

IIRC the argument in the McPhee book is that you'd steal fissile material rather than make it yourself. The book sketches a few scenarios in which UF6 is stolen off a laxly guarded truck (and recounts an accident where some ended up in an airport storage room by error). If the goal is not a bomb but merely to harm a lot of people, it suggests stealing miniscule quantities of Plutonium powder and then dispersing it into the ventilation systems of your choice.

The strangest thing about the book is that it assumes a future proliferation of nuclear material as nuclear energy becomes a huge part of the civilian power grid, and extrapolates that the supply chain will be weak somewhere sometime, but that proliferation never really came to pass, and to my understanding there's less material circulating around American highways now than there was in 1972 when it was published.

The other thing is the vast majority of UF6 in the fuel cycle is low-enriched (reactor grade), so it's not useful for building a nuclear weapon. Access to high-enriched uranium is very tightly controlled.

You can of course disperse radiological materials, but that's a dirty bomb, not a nuclear weapon. Nasty, but orders of magnitude less destructive potential than a real fission or thermonuclear device.

That same function could be fulfilled by better search engines though, even if they don't actually write a plan for you. I think you're right about it being more available now, and perhaps that is a bad thing. But you don't need AI for that, and it would happen anyway sooner or later even with just incremental increases in our ability to find information other humans have written. (Like a version of google books that didn't limit the view to a small preview, to use your specific example of a book where this info already exists)

Reply on news.ycombinator.com