Bakkot's comments

Re: reading level: do give the Simple English Wikipedia a try!

Not really. A lot of people at Google are on Macs. I think it's more that the Chrome team doesn't prioritize Java support, which I think shows their priorities are pretty much in order.

Nah, there's several other active, established markets already - SR2 wasn't even one of the top three.

The thing is, in the absence of collective action people choose to defect in prisoner's dilemmas. Giving people the option results in everyone defecting. Having it be preset results in everyone cooperating. Everyone cooperating is a better outcome for everyone.

Yeah, sure, but now suppose that you're going to decide the rule that everyone's car will follow. Are you still going to choose what amounts to defecting in the prisoner's dilemma?

Put it another way: this is one of those very rare occasion where collective cooperation (a la prisoner's dilemma) is possible. Shouldn't that... be the thing we want?

I've never understood this logic, especially since you're deciding on the rule for all cars, not just your car. Shouldn't you prefer that the rule be to minimize the number of people harmed, since this is the option which (when taken over all cars) will minimize the likelihood of you being harmed?

> Who in their right mind would get inside a car that is programmed to commit suicide in certain "ethical" circumstances?

Maybe you'll find this version more interesting: suppose the car has the opportunity to save a dozen people (who are not themselves at fault) by sacrificing you (or failing to do everything in its power to protect you). Should it?

If no, which seems to be the answer you think is obvious, consider that you are far more likely to find yourself as one of the dozen potential people saved than as the sacrifice, especially since we're deciding on the rule for all autonomous cars, not just yours. So following your logic makes it more likely for you to get killed.

I don't know. This is admittedly not something I know much about, but from poking around a bit, it looks like the Gather-Apply-Scatter model - or any other vertex-centric model - is not well suited to finding cycles of specific length. Compare eg GraphChi's triangle-counting code [1], which specifically notes the difficulties arising from having to maintain and work with large adjacency lists. I don't see a way around that for vertex-centric models.

That said, I haven't actually read your miner, so I don't know what it's doing or if something similar can be done for GAS-based frameworks. If someone who knows more wants to chime in, I'd be delighted to read more about this.

[1] https://github.com/GraphChi/graphchi-cpp/blob/master/example...

> Also, according to your response a domestic money transfer would suffer the same problems but these seem to work just fine (at least much better than international transfers).

Certainly they work better, but "just fine" is a much stronger claim and one I'd disagree with. I don't find myself spending money by wire transfer hardly ever, eg, and when I do it is a much larger affair then using cash. See also andrewla's comment here [1].

> Why does a mechanism that works just fine in between bank and customers and generally domestically just break down when country borders are involved?

Because banking systems and the regulations surrounding them are different in different countries, basically, and that adds lots of complications to an already extremely complex system. The bitcoin protocol is not different in different countries.

[1] https://news.ycombinator.com/item?id=8066251

Regulations are only possible because the technology to "transfer dollars electronically", as you say, requires lots of infrastructure and trust - the entire banking system, basically. If I want to send you a dollar electronically, I can't do so without using the banks. And the banks are both intrinsically and extrinsically motivated to impose regulations, which they can do by limiting access to their transfer-money services.

But access to the technology to transfer bitcoin does not require infrastructure and trust. I can send you a bitcoin without needing a bank or any other large authority. Moreover, I can do so relatively anonymously, and from anywhere in the world. It is therefore much, much harder to impose restrictions on moving bitcoin than moving USD or other non-digital currencies, because there are no large authorities capable of enforcing those restrictions.

(That is, the government can of course pass laws saying I can't send you bitcoin, or limiting the circumstances in which I could. But the most they can do is punish me if they can catch me - they can't actually stop it. Whereas banks do have the power to actually stop me from sending you USD. [Unless I want to do so physically, which is hard to do in quantity or over any distance.])

The answer to basically all of your questions is that to transfer money, you need to move money. This can be basically a promise of money, as with wire transfers, or physical, as you'd do by transporting bullion or cash.

The problem with using a promise to move money is that you have to trust whoever's promising. That works alright if there's a central authority, like a bank, but less well if you don't want to trust the authority, don't have access to the authority, or are unable to comply with the rules of the authority. Also it's kind of a shitty experience, as is. (You wouldn't pay for all of your Amazon purchases with wire transfers, I'd imagine.)

The problem with moving physical money is that it's difficult to do over long distances or en masse.

In order to solve the problems with existing money transfer, then, bitcoin needs to be able to do without a central authority and without using a physical representation of money. Which it accomplishes by allowing you to store money - not just a representation or promise thereof - digitally.

... Well that's an ancient typo. Corrected, thanks.

I did basically this in my first year of college! See [1].

(Note: code was never intended to be visible to the public, and this is old and bad. But hey, it works!)

http://kevingibbons.org/doublependulum.html

Well, I'm not going to have a compact answer for you, but to do so you need to develop some kind of self-reference. (Like Godel!) If you like thinking about this sort of thing, Raymond Smullyan has a lot of great writing - I'd recommend eg Forever Undecided or To Mock a Mockingbird for a more informal treatment, or First-Order Logic for a formal one.

One which doesn't exploit quantum-mechanical principles of computation.

Did you miss the bit in the OP where one of the coins has heads on both sides? The coin may or may not be biased, and the results of flipping it give you information about whether or not it is biased.

Explaining the bit you quoted: if you had perfect knowledge of the wind conditions, how hard the person flipped the coin, and so on, you would know precisely which side it would land on. That fact is determined. It's just because you are missing information that there's 50% probability of heads (for an unbiased coin). The probability comes out of your imperfect knowledge, and changes depending on your knowledge: for example, if you have some reason to believe the coin is biased, then you no longer think it's going to land on heads 50% of the time. Since one of the coins is biased, getting a long string of heads is reason to think that the coin they drew and are flipping is the biased coin. This information affects the probability you assign to the coin coming up heads.

The coin is the coin, but your information about the coin has changed. Probability is a fact about you, not a fact about the coin.

Here is perhaps a more visceral example: On any given day, your car has a 10% chance of having blown a wheel the previous night. If it has blown a wheel, every bump will feel jarring. If it hasn't blown a wheel, any given bump will feel jarring with 10% probability. You drive over a hundred bumps, and all feel jarring. Do you think the next bump will also feel jarring?

Yes, right? Because the fact that the last hundred bumps have been jarring means you probably blew a wheel last night. Even though 'previous history has no effect on future outcomes', previous history does give you information about the state of the world.

Edit: Or a better example, for this community. You're on a slightly flakey wifi connection, which sometimes drops a packet at random. Any given packet is dropped with probability 1/100. Also, any given time you connect to the router, the modem is down with probability 1/10, and all of your packets will get dropped. You connect, and the first hundred packets you send are dropped. What is the probability the next packet will get dropped? Very high, because now you know that the modem is probably down. The history of the connection gives you information about the state of the connection. Similarly, the history of coin toss results gives you information about the state of the coin.

(Why is this different from roulette? Because there the previous history doesn't give you information.)

Hm. Seems like it would make more sense for 'buyers' to submit btc along with the problem, which the market could then hold in escrow and release as soon as a proof passing the verifier was submitted. No need to trust anyone but the escrow service, between btc and machine proofs.

Wallbase is dying: see [1].

4walled.cc is a similar if much less polished service. Also see WallHaven.cc, which some of Wallbase's staff is working to make Wallbase's new home.

[1] http://www.reddit.com/r/YouShouldKnow/comments/1tbux9/ysk_ab...

Split second as in actually significantly under a second? I've never been able to get mine to take a picture without lighting up for very nearly a full second.