The abruptness of nuclear weapons

I think we probably had a decisive advantage (and could e.g. have prevented them from developing nuclear weapons) but didn't push it. I'd love to hear from someone with a better knowledge of the history though.

This is an important historical case study for predicting future technological change, and I agree is one of the strongest examples of discontinuous progress. This was a short and readable write-up of key points, and I appreciated the outlining of ways you might be wrong, to aid discussion (and it did lead to some good discussion). For these reasons, I curated it.

Based on my understanding, it was not known in 40s that US has 4 years advantage. Stalin started to claim "knowing nuclear secret" in 1947, but some US planners expected that it would take 10-20 years for Soviet Union to create the bomb.

Also, in 1949, the number of US nukes were not enough to stop Soviet army from ground invasion in Western Europe, which it would surely do in case of attack in Moscow.

Also, most of the soviet nuclear program was decentralised in secret unknown locations, which could not be destroyed without thermonuclear weapons or precise missiles, both non existed at the time.

Also US could not spend all its nukes on the first strike as it would mean effective disarmament, so the capabilities of the first strike was limited.

Thus I think that there was an advantage but not "decisive knowable" advantage, and such advantage in the case of nuclear weapons would be reached in 10 but not in 4 years.

I like the style of your analysis. I think your conclusion is wrong because of wonky details about World War 2. 4 years of technical progress at anything important, delivered for free on a silver platter, would have flipped the outcome of the war. 4 years of progress in fighter airplanes means you have total air superiority and can use enemy tanks for target practice. 4 years of progress in tanks means your tanks are effectively invulnerable against their opponents, and slice through enemy divisions with ease. 4 years of progress in manufacturing means you outproduce your opponent 2:1 at the front lines each and overwhelm them with numbers. 4 years of progress in cryptography means you know your opponent's every move and they are blind to your strategy.

Meanwhile, the kiloton bombs were only able to cripple cities "in a single mission" because nobody was watching out for them. Early nukes were so heavy that it's doubtful whether the slow clumsy planes that carried them could have arrived at their targets against determined opposition.

There is an important sense in which fission energy is discontinuously better than chemical energy, but it's not obvious that this translates into a discontinuity in strategic value per year of technological progress.

Separately, it seems like a 4 year lead in nuclear weapons would represent a decisive strategic advantage, which is much shorter than any other technology. My best guess is that a 2 year lead wouldn’t do it, but I’d love to hear an assessment of the situation from someone who understands the relevant history/​technology better than I do.

The US had a 4 year lead in nuclear weapons. The US tested its first nuclear weapon on July 16 1945. The Soviet Union tested its first nuclear weapon on August 29 1949. That is 4 years, 1 month and 13 days during which the US had a complete monopoly on nuclear weapons. Yet, during that time, the US did not and could not have used its nuclear weapons to assert superiority over the Soviet Union.

The US weapons of that era were all roughly in the 20kt range, and even as late as 1948, the US arsenal was less than 100 bombs. The delivery mechanism for these bombs were B-29 and B-36 bombers, which were relatively slow compared to the new jet-powered fighters and interceptors of the late '40s and early '50s. It's not clear that the US would have been able to drop a single nuclear bomb on the Soviet Union during that time, much less enough bombs to seriously dent a well-functioning industrial economy.

This gets at an important distinction between physical goods and software. With physical goods, there is often a long delay between invention and mass production. The US invented nuclear bombs in 1945. But it wasn't able to mass-produce them until after 1950. This is different from AI (and software products more generally) for which mass production is trivial, once the code has been written. It is for this reason that I do not think that nuclear bombs are a good analogy for AI risk.

I think a highly relevant detail here is that the biggest bottleneck in development of nuclear weapons is refinement of fissionable material which is a tremendously intense industrial process (and still remains the major deterrent for obtainment of nukes). Without it the development would have been a lot more abrupt (and likely successful on German side).

Just commenting that the progress to thermonuclear weapons represented another discontinuous jump (1-3 orders of magnitude).

Also, whether von Neumann was right depends on the probability for the cold war ending peacefully. If we retrospectively conclude that we had a 90% chance of total thermonuclear war (and just got very lucky in real life) then he was definitely right. If we instead argue from the observed outcome (or historical studies conclude that the eventual outcome was not due to luck but rather due to the inescapable logic of MAD), then he was totally nuts.

Near-misses are not necessarily a very strong guide to estimating retrospective risk. Both sides were incentivized to hide their fail-safes for escalation; to credibly commit to having a twitchy retaliation finger, and at the same time to not actually retaliate (the game is first chicken, then ultimatum, and never prisoner's dilemma). So I would be very wary of trusting the historical record on "what if Petrov had not kept a cool mind".

Looking at the history of nuclear weapons development, it seems like the development of rocket/missile technology for the purposes of delivering nuclear warheads, in addition to the rapid development of nuclear explosives themselves, gave a strategic advantage as well. One could make a case study out of the development of rocket/missile technology.

I agree that nuclear weapons are the best example for both discontinuity and for decisive strategic advantage; I also agree the United States possessed decisive strategic advantage with nuclear weapons, and that we elected not to employ it (by ignorance and/or the value alignment of the US government).

However, I am skeptical of the metrics we are considering here. What is the motivation for using cost/TNT equivalent? Intuitively, this seems to be the same mistake as measuring AGI's power in operations per second; there is a qualitative difference at work which such numbers obscure. Further, this is not the mechanism that militaries use in their planning. To illustrate the point, consider the last paragraph of page 3 in this memo (which is one of the sources provided in Gentzel's information hazards of the Cold War post here). I will quote one line in particular to prime the intuition:

(Single rather than multi-weapon attack on each target is the rule in order to conserve delivery forces.)

I think the key insight was hit on in the AI Impacts blog post which accompanied the cost analysis:

And in particular, there are an empty three orders of magnitude between the most chemical energy packed into a thing and the least nuclear energy packed into a thing.

Dollars and TNT equivalents give the illusion that these things are fungible; if we consider the bombing campaigns in WWII where more destructive power was delivered than with the nuclear bombing missions, we notice that those were entire campaigns and the nuclear bombings were missions. This is the implication of that big jump in energy: it only takes one successful long-range bomber to kill or cripple any city on the face of the earth.

I think our ability to reason about this, especially in a fashion where we can usefully compare it to AGI, is improved by sticking more closely to the strategic implications. One possibility: in lieu of cost, time; in lieu of energy, targets destroyed. So the new metric would be time per target. This seems to map more closely to considerations of how quickly an AGI can accomplish its goals.

Edit: accidentally a word

Promoted to frontpage.