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orthonormal comments on Being Half-Rational About Pascal's Wager is Even Worse - Less Wrong

19 Post author: Eliezer_Yudkowsky 18 April 2013 05:20AM

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Comment author: orthonormal 18 April 2013 08:58:03PM 4 points [-]

At least nine times out of ten in the history of physics, that heuristic probably did work. I agree that Fermi was wrong not to track down a perceived moderately small chance of a consequential breakthrough, but I can't believe with any confidence that his initial estimate was too low without the power of hindsight.

Comment author: Eliezer_Yudkowsky 18 April 2013 10:14:26PM 0 points [-]

Is there a good example of a conspiracy including physicists of the same prior fame as Rabi and Fermi (Szilard was then mostly an unknown) which was pursuing a 'remote possibility', of similar impact to nuclear weapons, that didn't pan out? Obviously we would have a much lower chance of hearing about it especially on a cursory reading of history books, but the chance is not zero, there are allegedly many such occasions, and the absence of any such known cases is not insignificant evidence. Bolded to help broadcast the question to random readers, in case somebody who knows of an example runs across this comment a year later. The only thing I can think of offhand in possibly arguably the same reference class would be polywell fusion today, assuming it doesn't pan out. There's no known conspiracy there, but there's a high-impact argument and Bussard previously working on the polywell.

Comment author: CarlShulman 24 April 2013 02:10:48AM 6 points [-]

Is there a good example of a conspiracy including physicists of the same prior fame as Rabi and Fermi (Szilard was then mostly an unknown) which was pursuing a 'remote possibility', of similar impact to nuclear weapons, that didn't pan out?

Do you have a set of examples where it did pan out, or are we just talking about a description crafted to describe a particular event?

Restricting to physicists cuts us from talking about other areas like bioweapons research, where indeed most of the "remote possibilities" of apocalyptic destruction don't pan out. Computer scientists did not produce AI in the 20th century, and it was thought of as at least a remote possibility.

For physicists, effective nuclear missile defense using beam weapons and interceptors did not pan out.

Comment author: private_messaging 25 April 2013 05:48:24PM *  4 points [-]

Radioactivity was discovered via "fluorescence is responsible for x-rays" idea that did not pan out...

There's a big number of fusion related attempts that did not pan out at all, there's fission of lithium which can't be used for a chain reaction and is only used for making tritium. There's hafnium triggering which might or might not pan out (and all the other isomers), and so on.

For the most part chasing or not chasing "wouldn't it be neat if" scenarios doesn't have much of effect on science, it seems - Fermi would still inevitably have discovered secondary neutrons even if he wasn't pursuing chain reaction (provided someone else didn't do that before him).

Comment author: private_messaging 20 April 2013 04:24:37AM *  4 points [-]

They were not hell bent on obtaining grant money for a fission bomb no-matter-what. The first thing they had to do was to measure fission cross sections over the neutron spectra, and in the counter-factual world where U235 does not exist but they detected fission anyway (because high energy neutrons do fission U238), they did the founding effort for the accelerator driven fission, the fission products of which heal the cancer around the world (the radiation sources in medicine would still be produced somehow), and in that world maybe you go on using it in some other sequence going on how Szilard was wrong and Fermi dramatically overestimated and how obviously the chance was far lower because they were talking of one isotope and not a single isotope works and how stupid it is to think that fissioning and producing neutrons is enough for chain reaction (the bar on that is tad higher) etc etc. In that alternate world, today, maybe there's even an enormous project of trying to produce - in an accelerator or something more clever - enough plutonium to kick-start breeder reactor economy. Or maybe we got fusion power plants there, because a lot of effort was put into that (plus Manhattan project never happened and some scientists perhaps didn't get cancer) . edit: Or actually, combination of the two could have happened at some point much later than 1945: sub-unity tokamak which produces neutrons via fusion, to irradiate uranium-238 and breed enough plutonium to kick start breeder reactors. Or maybe not, because it could have took a long while there until someone measures properties of plutonium. Either way, Fermi and Szilard end up looking awesome.

Comment author: itaibn0 21 April 2013 12:54:39PM 0 points [-]

How about the original Pascal's wager? It was made by a famed mathematician rather than a famed physicist, and it wasn't a conspiracy, but it's definitely in the same reference frame.