The population boom to the Malthusian limit (and a lower Malthusian limit for AI than humans) is an overwhelmingly important impact (on growth, economic activity, etc) that you don't mention, but that is regularly emphasized.

Running people faster or slower and keeping backups came immediately to mind, and Wikipedia adds space travel, but those three by themselves don't seem like they change that much.

Do you think mathematics and CS, or improvement of brain emulation software and other AI, wouldn't go much further with 1000 people working for a million years, than 100 million people working for 10 years?

Federation of American Scientists:

The only proven and practical source for the large quantities of neutrons needed to make plutonium at a reasonable speed is a nuclear reactor in which a controlled but self-sustaining 235 U fission chain reaction takes place.

Discussion of the particle accelerator route which would enable the bootstrapping of a non U-235 route eventually (producing a critical mass of 10+ kg of plutonium using superconductors and huge amounts of energy and accelerator time), but only with much increased difficulty:

Wilson died in 2000 but a paper he wrote on this topic in 1976 has now found its way onto the arXiv and it highlights some thought-provoking ideas.

At the time, Wilson was director of Fermilab where he was building an accelerator called the Energy Doubler/Saver, which employed superconducting magnets to steer a beam of high energy protons in a giant circle. These protons were to have energies of up to 1000 GeV.

The Energy Doubler was special because it was the first time superconductivity had been used on a large scale, something that had significant implications for the amount of juice required to make the thing work. “One consequence of the application of superconductivity to accelerator construction is that the power consumption of accelerators will become much smaller,” said Wilson. And that raised an interesting prospect.

Imagine the protons in this accelerator are sent into a block of uranium. Each proton might then be expected to generate a shower of some 60,000 neutrons in the material and most of these would go on to be absorbed by the nuclei to form 60,000 plutonium atoms. When burned in a nuclear reactor, each plutonium atom produces 0.2 GeV of fission energy. So 60,000 of them would produce 12,000 GeV.

Using this back-of-an-envelope calculation, Wilson worked out that a single 1000 GeV proton could lead to the release of 12,000 GeV of fission energy. Of course, this neglects all the messy fine details in which large amounts of energy can be lost. For example, it takes some 20MW of power to produce an 0.2MW beam in the Energy Doubler.

But even with those kinds of losses, it certainly seems worthwhile to study the process in more detail to see if overall energy production is possible.

We have worked with some educators whose eyes were opened to the misalignment of services and needs, and they learned to use data, to identify appropriate interventions, and keep records to make accountability possible. We’ve seen these innovators close their achievement gaps while raising achievement of the top. But, those around them didn’t see this as replicable.

Do you mean substantially reduced, or actually closed? All of the other claims are familiar and have citations, but this one doesn't, and a data-driven process to fully close achievement gaps would be a major advance, and yet one that has gone unreported (or very underreported) in the academic literature.

You could email good academics studying achievement gaps, e.g. economist Roland Fryer at Harvard has a number of studies on randomized trials of gap-closing interventions, and hasn't yet found something so effective. He also has demonstrated he can get large studies done and funded. Regardless of what local schools think, if you can show good data (or work with them to help them get such data without violating NDAs) confirming this to such academics then you will get a significant response and national attention from wonks and foundations to help scale up better practices.

Fryer would be able to get much more done than we can here.

"If you invest your money now, you might be able to make something like 10% annually with some risk."

10% is rather questionable as a long-term prediction: only the most successful equities markets in the world managed close to that in the last century, and many disappeared entirely. After corrections for inflation, survivorship, taxes, and so forth real returns are closer to world growth rates.

Speaking of this, does anyone know of any LW posts or other articles about how to make the most of idle capital with some risk?

The ultra-standard advice of economists is index funds. They beat the overwhelming majority of actively managed funds in any given year and outperform active management (even the rare few hedge and private equity funds that seem to have real repeatable skill just raise fees until the marginal investor is indifferent) via low fees and just holding the diversified market. Basically, it's very hard to beat the market, and management and trading fees are costly, so index funds don't try to do the former and clean up on the latter.

Anna and I invest with Vanguard, which we picked based on low fees, large size, and good reputation, but almost any brokerage will offer them. You can just go to one of their websites with your bank information at hand and get things set up quite rapidly (it took less than an hour for us to invest at the Vanguard website in global equity index funds, seeking high diversification and exposure to the historical equity premium).

You can search LW for "index fund(s)" if you want, and find some economists (James Miller and maybe Robin Hanson) among others saying this, but I would go for index funds based on the track record and the overwhelming consensus of financial economists rather than LW opinion.

It seems like this ought to violate the Hansonian principle somehow but I'm not sure to articulate it...

Hanson endorses SIA. So he would multiply the possible worlds by the number of copies of his observations therein. A world with 3^^^3 copies of him would get a 3^^^3 anthropic update. A world with only one copy of his observations that can affect 3^^^^3 creatures with different observations would get no such probability boost.

Or if one was a one-boxer on Newcomb one might think of the utility of ordinary payoffs in the first world as multiplied by the 3^^^3 copies who get them.

I try to avoid Enrico-Fermi-style "ten percent" underestimates about what might actually have an impact.

But as gwern and other commenters showed, your characterization of accessible chain reactions as an easily drawn implication of then-known physics was wrong.

The best case for bias on Fermi's part in that post is the partially (but not very) independent claim that:

Fermi is also the one who said that nuclear energy was fifty years off in the unlikely event it could be done at all, two years (IIRC) before Fermi himself oversaw the construction of the first nuclear pile.

But you didn't give a citation or quote for that.

And you suggest that

Szilard and Rabi saw the logic in advance of the fact, not just afterward - though not in those exact terms; they just saw the physical logic, and then didn't adjust it downward for 'absurdity' or with more complicated rationalizations

But you only present evidence that they cared about a 10% probability (and Szilard was selected from history in part because of his right-tail estimate).

I hadn't considered the problem of finite axioms giving you unboundedly large likelihood ratios over your exact situation.

Really? People have been raising this (worlds with big payoffs and in which your observations are not correspondingly common) from the very beginning. E.g. in the comments of your original Pascal's Mugging post in 2007, Michael Vassar raised the point:

The guy with the button could threaten to make an extra-planar factory farm containing 3^^^^^3 pigs instead of killing 3^^^^3 humans. If utilities are additive, that would be worse.

and you replied:

Congratulations, you made my brain asplode.

Wei Dai and Rolf Nelson discussed the issue further in the comments there, and from different angles. And it is the obvious pattern-completion for "this argument gives me nigh-infinite certainty given its assumptions---now do I have nigh-infinite certainty in the assumptions?" i.e. Probing the Improbable issues. This is how I explained the unbounded payoffs issue to Steven Kaas when he asked for feedback on earlier drafts of his recent post about expected value and extreme payoffs (note how he talks about our uncertainty re anthropics and the other conditions required for Hanson's anthropic argument to go through).

OK, but if you're willing to buy all that, then the expected payoff in some kind of stuff for almost any action (setting aside opportunity costs and empirical stabilizing assumptions) is also going to be cosmically large, since you have some prior probability on conditions like those in the bullet pointed list blocking the leverage considerations.

I don't think many people have prior convictions about decision theory before they study it.

You picked literally the most extreme case, where 52.5% of undergraduates answered "insufficiently familiar," followed by 46.1% for A- vs B-theory of time. The average for all other questions was just under 12%, 8.8% for moral realism, 0.9% for free will, 0% for atheism.

For Newcomb most undergrads are not familiar enough with the problem to have an opinion, but people do have differing strong intuitions on first encountering the problem. However, the swing in favor of two boxing for Newcomb from those undergrads with an opinion to target faculty is a relatively large chance in ratio of support from 16:18 to 31:21. Learning about dominance arguments and so forth really does sway people.

I just looked through all the PhilPapers survey questions, comparing undergrads vs target faculty with the coarse breakdown. For each question I selected the plurality non-"Other" (which included insufficient knowledge, not sure, etc) option, and recorded the swing in opinion from philosophy undergraduates to philosophy professors, to within a point.

Now, there is a lot of selection filter between undergraduates and target faculty; the faculty will tend to be people who think philosophy is more worthwhile, keen on graduate education, and will be smarter with associated views (e.g. atheism is higher at more elite schools and among those with higher GRE scores, which correlate with becoming faculty). This is not a direct measure of the effect of philosophy training and study on particular people, but it's still interesting as suggestive evidence about the degree to which philosophical study and careers inform (or otherwise influence) philosophical opinion.

In my Google Doc I recorded an average swing from undergraduates to target faculty of ~10% in the direction of the target faculty plurality, which is respectable but not huge. Compatibilism rises 18 points, atheism 10 points, moral realism 12 points, physicalism 4 points, two-boxing by 15, deontology by 10, egalitarianism by 10. Zombies and personal identity/teletransporter barely move. The biggest swing is ~30 points in favor of non-skeptical realism about the external world.

That said, I agree the LWers who answered the survey questions in a LW thread were overconfident, that the average level of philosophical thinking here is lower quality than you would find in elite philosophy students and faculty (although not uniformly, if for no other reason because some such people read and comment at LW), and that some prominent posters are pretty overconfident (although note that philosophers themselves tend to be very confident in their views despite the similarly confident disagreement of their epistemic peers with rival views, far more than your account would suggest is reasonable, or than I would).

The problem is that you seem to be introducing one dubious piece to deal with another. Why is the hypothesis that those bullet points hold infinitesimally unlikely rather than very unlikely in the first place?