Home Built Scanning Tunneling Microscope Electronics - <AUTHOR> http://dberard.com/home-built-stm/electronics/ <comment><USER2> Knowing nothing about Electron Microscopes, I found the design of the motion mechanism very clever: [http://web.archive.org/web/20130927064954/http://www.geociti...](http://web.archive.org/web/20130927064954/http://www.geocities.com/spm_stm/Disk_Scanner_Exp.html)

[http://dberard.com/home-built-stm/scan-head/](http://dberard.com/home-built- stm/scan-head/)

<comment><USER3> Also of interest is that the inventor, John Alexander, submitted a patent application (US5866902), then withdrew the application. Perhaps this was done to establish prior art in the USPTO's database, and prevent someone else from patenting it?

</comment></comment><comment><USER4> This is super cool. Bookmarked. It would be awesome to see it working. I wonder if there is a video on this.

This project uses PI control in the feedback loop. I am curious if the author also tried PID control, that would have been faster with correct tuning.

</comment><comment><USER5> Wow. Stuff like this makes me want to get off my ass and do something cool. Really reinvigorates my passion for hands-on science and engineering, as opposed to the maths and code that I usually look at.

</comment><comment><USER6> On a related note, Ben Krasnow built a SEM in his garage. Search YouTube for his channel.

<comment><USER2> [https://www.youtube.com/watch?v=VdjYVF4a6iU](https://www.youtube.com/watch?v=VdjYVF4a6iU)

Ben Karsnow's channel is really inspiring. With every video, he pushes the limits of what I thought it was possible to do in your garage.

</comment></comment><comment><USER7> I'm looking forward to something like this rescuing a few harddrive platters.

</comment><comment><USER8> Nice to know they're not magic after all :) Very inspiring.

</comment><comment><USER9> Nice project. Had no idea the electronics were so simple.</comment>


Ask HN: Anyone interested in a HN Slack group? - <AUTHOR>

I've always enjoyed the #startups channel on freenode, but I hate IRC and would love to have another venue to connect to fellow HNers. <comment><USER2> There is already a startup slack group which is active: startupfoundation.slack.com

<comment><USER3> also [http://hackernews.kickoffpages.com/](http://hackernews.kickoffpages.com/) and [http://www.hashtagstartup.co/](http://www.hashtagstartup.co/)</comment></comment>


Why we should care about the Nate Silver vs. Nassim Taleb Twitter war - <AUTHOR> https://towardsdatascience.com/why-you-should-care-about-the-nate-silver-vs-nassim-taleb-twitter-war-a581dce1f5fc <comment><USER2> This is an intellectually confused post. It is so unclear and muddled that only a charitable reader would suppose the author understands the mathematical and modeling issues here. I'm surprised the author published it in this form - you don't want to jump into a controversy like this with such an unclear discussion.

As just one example, the whole digression on a "decision boundary" is conceptually mistaken. Once you report a posterior probability, it's up to the user to establish a simple real number threshold for placing a bet (if we're talking about means to put skin in the game). The posterior you just learned holds all information, your only action is to threshold it. That's the Neyman- Pearson lemma.

If you allow generalizations to interval-valued probability, which might be sensible under these conditions, the situation gets more complicated. But the writer of the post did not mention this.

Another place this came out is his initial discussion of aleatory vs. epistemic uncertainty — this can be done clearly, but here we read:

> Aleatory uncertainty is concerned with the fundamental system (probability > of rolling a six on a standard die). Epistemic uncertainty is concerned with > the uncertainty of the system (how many sides does a die have? And what is > the probability of rolling a six?).

This is just not helpful. He has said "probability of rolling a six" twice.

Source: do UQ in day job.

<comment><USER3> Unlikely. Taleb seems to like how his argument has been summarised.

The crux of the issue taleb has with silver is showing probabilities without making a decision/declaration is cowardly. When asked about making a prediction he says one thing then follows it up with a " but don't be surprised if it could be completely random." And that's the point - the fact he covers his ass is the problem. Election forecasting is hard so don't pretend you know something you don't if you won't stake something on your predictions. Oh so it could be anything and you don't want to be held accountable? Then don't say a damn thing. Basically Silver never wants to be held accountable for his models but always have uncertainty covering his ass as a cop out. so I'm With taleb on this one. Either silver makes a claim and sticks with it or don't show probabilities and pretend he knows things

<comment><USER4> I disagree. Probabilities can be useful even if they're not 0% or 100%. For example weather forecasts often give the probability of rain. My plans will be different if the probability is 20% vs 80%. My plans don't tend to vary based on who wins the election, but I imagine that that information is very useful to some people.

And if your data is telling you to be 80% sure, I don't think you should fudge it and claim 100%. Report the uncertainty that you actually have.

<comment><USER5> With the weather man, I could keep track of when it rains and doesn't. If it rains significantly more or less than 80% of the time they say there's an 80% chance of rain, I can say that their model is bad.

I can't think of a similar way to evaluate Silver's election forecasting model. They very clearly aren't independent probabilities, and his model changes significantly from cycle to cycle. Was his model good in 2012 when every state went to where he predicted the likely probability was? Was it bad when his model said Hillary had a 71.4% chance of winning?

<comment><USER6> They do not only predict top-line presidential results, but every race, in every state, for president, House, and Senate. Non-independence is accounted for in the model, so they have no qualms about you judging them by the calibration of their predictions, I. e. You want roughly 60% of their "60%" forecasts to be right, and 40% to be wrong. If all of the races they predict 60/40 go to the more likely candidate, they themselves consider this a failure: [https://fivethirtyeight.com/features/how- fivethirtyeights-20...](https://fivethirtyeight.com/features/how- fivethirtyeights-2018-midterm-forecasts-did/)

</comment></comment></comment></comment></comment><comment><USER7> The article seems like an oversimplification of the underlying dispute.

\- It's not necessary or even useful to define an arbitrary "decision boundary" unless you actually have to make a decision. From a Bayesian perspective, a probability stands for itself: 100% means the event is certain to occur, 50% means you have no idea, and numbers in between convey varying levels of certainty. In reality, 538's predictions are not true Bayesian probabilities because they don't take epistemic uncertainty into account, but that's a totally different issue.

\- "Wild fluctuations in a prediction" from new information are absolutely a "normal part of forecasting" - _sometimes_. If I'm planning to flip two coins, the probability of getting two heads is 25%; but once I flip the first coin, the probability changes to either 50% (if I get heads) or 0% (if I get tails). In the case of Comey reopening the investigation, even if the model had included a probability of that happening, it would have been low and thus wouldn't affect the overall forecast much. But once that low probability became a certainty, you would expect a sudden swing. The real question is whether 538's predictions are more swingy than they logically should be (particularly earlier on), but again, that's a different issue.

<comment><USER8> Seems like in addition to whether they're more swingy than they should be, are they being presented in a way that is interpreted as more certain or authoritative than they can possibly claim?

<comment><USER9> The 2016 election _was_ swingy and it _was_ uncertain.

In 2008 and 2012, the political media was myopically focused on the twists and turns of the horse race and called it 50-50 dead even. Nate Silver's 538 modeled the election as basically stable with only small polling shifts, and the only change in the last month was a steady decline in the remaining time that McCain (or Romney) had to significantly shift the polls.

In 2016, the political media treated the election as if Hillary had a lock on it, and entreated us not to get swept up in the daily swings in the polls. Meanwhile, Nate Silver's model swung wildly with the polls, and Nate went on the media to emphasize the uncertainty of the election. Both candidates were disliked, and a large portion of the electorate was undecided right up until the last week of the election.

I remember the following exchange in one interview:

Interviewer: If you say that Donald Trump has a 33% chance to win, what's the chance that he actually wins? Nate Silver: One in three. I'm predicting a one in three chance that Donald Trump wins in November.

As for the authoritativeness of their presentation, FiveThirtyEight has a really beautiful forecast that presents their 2018 prediction as a probability distribution:

[https://projects.fivethirtyeight.com/2018-midterm- election-f...](https://projects.fivethirtyeight.com/2018-midterm-election- forecast/house/)

<comment><USER10> > _The 2016 election was swingy and it was uncertain._

In retrospect. In real life, only a few pundits called it from the start (even explaining the mechanics, including Taleb and that Dilbert guy).

Most of the press and pundits was all certain about a specific outcome until the very last minute.

<comment><USER9> The Real Clear Politics polling aggregator showed nearly a 10 point jump for Hillary Clinton after "grab em by the pussy" came out. That lead then eroded back to the mean over the course of the month.

That's what I mean by swingy. Nothing in 2008 or 2012 shifted the polls like that. The polls in those elections stayed within a 2 point band the whole way. That level of volatility was clear in the polls well in advance of the election.

(And, 15% of the electorate was effectively undecided with 2 weeks to go, which is much higher than it was in 2008 or 2012).

Such swings are also what Taleb and the author of this article are criticizing Nate Silver for.

</comment></comment></comment></comment></comment><comment><USER11> To try and explain Taleb's argument as simply as possible: If someone tells you today that an event is 100% certain, and tomorrow tells you that it is impossible, then you intuitively will not trust their forecasting. If it's certain, then it's certain not to be impossible tomorrow

Now if someone tells you something is a 90% chance today, and a 10% chance tomorrow, again you don't trust their predictions.

There is a probability associated with "changes in probability". The probability of going from 100 to 0 should intuitively be 0%. The probability of going from 90 to 10 intuitively must be something like 20% (it's like 80 of the 90s "didn't happen", with a probability of 20).

A key point is that you can add this up every day, if something goes from 90->10->90 then it's even more unlikely than going 90->10.

So if you extend that intuition, put some real maths behind it, you can tell whether something is "likely to be a real probability" by the rate at which it changes. And if you have lots and lots of repeated predictions, you can be confident that something isn't a good probability (every timeseries has like a <10% chance of doing exactly what it does, so their combined probability [of being good probabilities] is like 0).

Now Nate Silver accepts this, but says that he's not actually putting a probability on the event in the future, but some non-existent "probability on that event in the future if the future was now". But that doesn't correspond to anything useful or measurable (it's untestable!!), and most people will assume it follows the normal meaning of probability, and it's honestly just silly.

<comment><USER12> I've always treated 538's forecasts as meaning nothing more or less than "We have a model, we fed the current data into it and ran N simulations of the event, and in X% of those simulations, this was the result". Which, as I understand it, is literally how they're generated.

Any discussion of the accuracy of the model (which should be the only thing that admits debate) has to be retrospective. Just saying "well the forecasts changed" doesn't inherently discredit the model, especially because things like elections turn out to be highly sensitive to tiny variations (even something as simple as a rainy election day in a few key precincts can completely flip an outcome).

<comment><USER13> Yes but that's not how the proles understand the blog. They take it as "x has a y % chance of happening".

Which is Taleb's beef with it. The commoner thinks its Silver putting his money on something, but when it doesn't happen he says "well I didn't say _that_".

And it in the day and age of more robust machine learning models, that the 538 models are so volatile is a pretty weak excuse.

<comment><USER14> Humans are volatile. Politics even more so.

Our options aren't "high confidence converging predictions, or 538".

The options in the current era for understanding of the electorate's mood are "overly confident individual polls, poorly analyzed with completely inadequate models", vs "538-style epistemically humble models accompanied by discussions of their confidence, which can be scored in aggregate after each election".

I'll take 538 any day.

<comment><USER13> But it's not about you. Just being on this forum puts you in the critical thinking 1%.

538 fails in that most people think that the daily stats are Silver's betting positions. He "predicted the 2008 election."

We understand the difference, but the crying campaign staffers last November did not.

<comment><USER15> > We understand the difference, but the crying campaign staffers last November > did not.

Campaigns aren't relying on Silver's model.

</comment></comment></comment></comment></comment></comment><comment><USER16> I appreciate the stuff about two types of certainties, but where are they actually arguing anything remotely relevant like that? As far as I can tell, based on what I see bubble up to my twitter feed and what tweets are displayed in this post, the disagreement is based entirely on Talib's claim that Silver switched his prediction from 80% to 50%. This really has nothing to do with actually understanding probability or prediction models. It's just Talib sharing some other pundit's deliberate misinterpretation of a single phrase deliberately taken out of context in an interview with Silver.

I don't think their disagreement has much to do with science or mathematics. I think the two guys have big online followings, each leaning heavily toward two different political ideologies, and the two leaders just have to try to beat each other up on a Twitter to decide which side is better.

</comment><comment><USER17> _He should not have accepted the honor if he didn't call a winner in any of the states!_

And he didn't, as far as I recall. I remember him saying something to the effect of "that isn't that impressive, even a simple method looking at polls would have gotten nearly all the states correct". Don't confuse what other people focus on for something he is boasting about.

</comment><comment><USER18> It's not clear to me what the author is getting at. 538 is good at aggregating polls and showing some probability. The author complains that's not enough because a non zero probability of the less probable outcome gives 538 too much cover when the less probable outcome occurs.

Isn't that a shared characteristic of any other model dealing with probabilities?

Is the author trying to say Nate Silver gets too much spotlight considering he doesn't guarantee outcomes?

I didn't sell in 2008 and kept buying. I have the same strategy today. Not sure if that also makes me a guru if that's the bar (as the author applies it to Taleb).

Disclaimer: not a mathematician

</comment><comment><USER19> If 538 is trying to do aleatory probabilities, then it is kinda like a broken clock - right sometimes, but as a tool for answers about future events of any complexity (i.e. the real world, where actions have consequences, and errors can be grave..), I'd avoid putting one's confidence in something that claims it has a simple/'linear' relationship to the real future.

It is also a cop out to claim "everybody who thinks probabilities based on initial poll responses are not representative of eventual votes" must clearly not understand probability. Maybe I am straw-manning or just don't understand the actual disagreement.

As a poll aggregator? I'm sure it's probably a fabulous tool for past, historical, _observed_ data. The brand itself, probably even more valuable, as a symbol with some sort of social authority in certain circles, I guess.

Anybody who reads my comment history will see I have obviously become a Taleb stan, but his approach seems right to me: "show me the money". Which in his case means mathematical papers of proofs primarily, actual money, second.

<comment><USER20> Taleb is just mixing up the nowcast and the forecast, even after being corrected many times.

<comment><USER11> I think he would say that the "nowcast" is so useless and deceptive to be malpractice, since everyone will interpret it as a forecast, and even if they didn't it's not in any way useful. Which I agree with (unsurprising since I've semi-invented it as an opinion for another person).

<comment><USER21> It's only useless and deceptive if you willfully do absolutely nothing to understand what it is, or how it differs from the other models 538 has, which apparently is the case for Taleb.

<comment><USER11> Or in other words, you're 99% of people who will ever hear the number

<comment><USER21> It explains on the website what it is. And if you are going to rail against something, you should understand what you are railing against.

</comment></comment></comment></comment></comment></comment><comment><USER22> Nate Silver built an aleatory model whereby low probability high effect events (Comey reopening the investigation on eve of the election) are discounted because if you add enough of these potential disruptive events the model will be 50%-50% and that has no value to anybody. Who wants to read an article that said "election forecast 50-50" every day.

If a 538 model says one outcome is 75% probable, it really should come with a giant caveat saying "at current trends assuming nothing out of the ordinary occurs". Taleb's beef is that if that is the case, the 75% does not mean in reality this result is 75% likely to happen.

What is a really interesting takeaway is that if in an event where the outcome you desire based appears unlikely, your job is introduce as much previously undefined or discounted uncertainty. Ideally you engineer a black swan event or at least do what you can to make it happen. This would be fun to model from a game-theory approach instead.

<comment><USER23> > What is a really interesting takeaway is that if in an event where the > outcome you desire based appears unlikely, your job is introduce as much > previously undefined or discounted uncertainty. Ideally you engineer a black > swan event or at least do what you can to make it happen. This would be fun > to model from a game-theory approach instead.

In chess, if you are behind, John Nunn's two recommended strategies are "grim defence" (if your opponent's advantage is not so large as to make it easy for them to force a win) and "create confusion": create complicated tactical situations and hope your opponent makes a mistake. The farther behind you are, the more appealing "create confusion" gets by comparison.

</comment></comment><comment><USER24> I'm confused by the existence of this article. Comparing the accuracy of two probabilistic predictors is pretty much a solved problem. (At least in situations where the two predictors have both made predictions about a fairly large number of events in the same set, S.) Just add up the log scores for both predictors and see which does better. [1]

[1] [https://en.wikipedia.org/wiki/Scoring_rule#Logarithmic_scori...](https://en.wikipedia.org/wiki/Scoring_rule#Logarithmic_scoring_rule)

Another thought: Although the author didn't lie about its meaning, I thought the graph "Stated Probabilities Compared with Average Portions" was visually misleading. At a casual glance, it appeared that 538 was all over the place with its senate predictions. But if you look closer, you can see that many of the red data points are at 0 or 0.5 or 1. This suggests that these data points represent the outcome of just 1 or 2 elections, which isn't really enough to say that 538 is doing particularly badly.

</comment><comment><USER25> I'm still waiting for somebody to talk about how tightly coupled Nate Silver's forecasts are to the political processes he attempts to forecast.

What if Nate Silver were to run around on the football field before each play whispering in the players' ears about the how likely they are to win, according to his latest forecast. Imagine that they believed in him, or at least felt some degree of superstition when he came around.

I just think there's something innately flawed about public forecasting of an election. Mathematically and maybe even ethically. I'm still trying to figure out how to articulate why I feel that way.

It could even be argued that polling itself could influence opinions by introducing bias at a critical moment when someone is being asked to consider who they are voting for. What if that's the moment when they make up their mind?

P.S. [https://www.frontiersin.org/articles/10.3389/fphy.2015.00077...](https://www.frontiersin.org/articles/10.3389/fphy.2015.00077/full)

<comment><USER26> _I just think there 's something innately flawed about public forecasting of an election._

It used to be the case in France that you weren't allowed to publish polls two weeks before an election for just this reason. They eventually scrapped this with the argument that the all 'elites' had access to internal and private polls anyway so all you where doing was denying the 'people' the same access to information that the 'elites' had.

 _It could even be argued that polling itself could influence opinions by introducing bias at a critical moment when someone is being asked to consider who they are voting for._

This is a pretty well known effect, to the point that many political strategists try to avoid publishing or drawing attention to polls showing their candidate too far ahead in case it makes voters complacent and decide to stay home. The ideal situation is to make people convinced the polls show the candidates tied 50-50 going in to the election and that 'your' vote could easily swing the whole election.

<comment><USER27> This is slightly wrong. It was initially one week, not two. It was changed because it was unconstitutional, as it limited freedom of expression too much, not because it was useless or anything to do with elite vs people. And it still exists, limited to the day of the election and the day before. Source: [https://www.conseil-constitutionnel.fr/nouveaux-cahiers- du-c...](https://www.conseil-constitutionnel.fr/nouveaux-cahiers-du-conseil- constitutionnel/la-reglementation-des-sondages-et-l-election-presidentielle)

</comment></comment></comment><comment><USER28> Author does informative critique of 538. I'm not sure at all that it has anything to do with Silver vs Taleb twitter war though. It's more like premise for expressing author's own thoughts.

However I totally dig what 538 does and appreciate their analysis. I understand that there is a complex underlying model with many parameters taken subjectively. The results of Monte Carlo runs of this model are very interesting to me. The fact that they describe distribution of outcomes and not just a single number is important property of a Monte Carlo model and I would have an issue if that wouldn't provide that info. If I would like to analyze complex event that has lots of moving parts and uncertainties I would also build a model to see what kind of distribution I would get. The fact that somebody published results of their model is quite useful.

The analogy would be European and American weather models - no one say that their results are exact and everybody understand that uncertainty in result comes from inherent uncertainty of initial state as well as shortcuts and approximations each of the model takes. No one says that the results of these models are useless because of that. And everybody finds it valuable if weather forecast predicts rain tomorrow with 40% chance. So I don't see how political prediction is only valuable (by the words of the author) if it comes without probabilities attached to it.

</comment><comment><USER29> > Practically what this means is that they do not predict a winner or looser > but instead report a likelihood

Yes, this is good. It means that you can evaluate their accuracy to a greater degree than % of times correct.

> Further complicating the issue, these predictions are reported as point > estimates

They've learned from this, and now show their distribution of results very clearly. However, there's nothing mathematically fraught about reporting a prediction as a point estimate.

> The problem is that models are not perfect replicas of the real world and > are, as a matter of fact, always wrong in some way.

...yes? And so what? This is a _fully general counterargument_ to all of science.

> Predictions have two types of uncertainty; aleatory and epistemic.

Don't say things like this with 100% certainty when your source itself says "the validity of this categorization is open to debate", and also when your source is Wikipedia.

> However, as you can see, there is still a noticable variation of 2–5% of > actual proportion to predictions. This is a signal of un-addressed epistemic > uncertainty. It also means you cannot take one of these forecast > probabilities at face value.

Models aren't perfect. Also, 538 is very careful to address their epistemic uncertainty! They also try very hard to not change their models significantly after they publish them, in order to avoid letting their personal biases tinker with the results.

This post goes out of it's way a to avoid mentioning that there are pretty well established ways of measuring the accuracy of predictions, instead using things like "look, it's not quite a line" and "look, the line went up and down before the election".

If you're interested in actually reading about this from a mathematical viewpoint, read Taleb's paper, which has some actually interesting thoughts on why 538's algorithms are too eager, or read Madeka's paper, which includes comparisons of 538 to other people trying to make predictions, and finds that actually, they were better than most other news sources.

[https://arxiv.org/pdf/1703.06351.pdf](https://arxiv.org/pdf/1703.06351.pdf)

[https://arxiv.org/pdf/1704.02664.pdf](https://arxiv.org/pdf/1704.02664.pdf)

</comment><comment><USER30> All of which increases the probability that I will ignore Taleb's tweets. I follow people who are smart enough to disagree in a civil manner, and smart enough to recognise that there may be things one doesn't know.

The way he talked to renowned classicist (and feminist, which seemed to be a problem for Taleb) Dame Mary Beard in another spat was disgusting. Trying to impose statistical certainty on ancient history ended up making him look pretty dumb to everyone but him.

<comment><USER31> The problem is that the smart arrogant jerk may have the right answer sometimes when it counts, while being a pain in the ass the rest of the time. Better just to stay open to all feeds. He does come off as an arrogant dick, wow.

<comment><USER32> I used to look at things this way, with a "just filter out the rudeness" mindset. However in practical terms I think listening to somebody's rudeness does have a really big cost (to estimate: how much would you need to be paid to make it worth your time to listen to rudeness for an hour?)

</comment></comment></comment><comment><USER33> Shouldn't a guy like Taleb be able to propose a bet with Silver that demonstrates he (Taleb) is right?

<comment><USER34> Best solution proposed here! Put your money where your mouth is Taleb and Silver!

Btw, I read 3 of Taleb's books, 1 from Nate Silver. Both are pretty good. Taleb is the more original, but also more often-objectionable.

<comment><USER26> _Best solution proposed here_

So what should the bet be? As far as I can tell they're not disagreeing on anything that can easily be reduced to a bet

<comment><USER35> Nate calls the chances like 80:20 Clinton:Trump. Taleb takes the side: 100,000 USD that Trump wins. If Trump wins, Nate pays 500,000 to Taleb. If Clinton wins, than Taleb pays 100,000 USD to Nate.

Do this for each election.

<comment><USER26> But that doesn't seem to be the nature of their disagreement. Taleb's main complaint seems to be about how the swings in the prediction probabilities far out from the event indicates a fundamental flaw in how the underlying model uses probability.

That being said it would be a fun little exercise to see who much money would be made if they bet had $1 on every race 538 predicted in 2016 and 2018 using the model odds.

<comment><USER33> It doesn't need to be a simple bet. It could incorporate the volatility which Taleb might believe shouldn't be present in an unflawed model.

<comment><USER35> Indeed after skimming through the paper[1] (I find it hard to grasp without a solid background) it seems that Taleb wants to play this game every day before the election and expects to come out ahead on election day when all the bets are settled.

[1] [https://arxiv.org/pdf/1703.06351.pdf](https://arxiv.org/pdf/1703.06351.pdf)

</comment></comment></comment></comment></comment></comment></comment><comment><USER36> I liked the first chapter of "Fooled by Randomness," but I stopped reading the book when each chapter regurgitated the same points, each more nihilistic than the last. Perhaps Taleb should concentrate on the accuracy of his own predictions:

[https://www.businessinsider.com/taleb-every-single-human- bei...](https://www.businessinsider.com/taleb-every-single-human-being-should- short-treasuries-2010-2)

>>> "every single human being" should bet U.S. Treasury bonds will decline.

>>> Short the S&P vs Long Gold, in a 5 to 1 ratio. By gold Taleb means a basket of precious metals including gold.

The second trade would have lost $125k for every $10k invested in gold and $50k invested in SPY.

Did he miscalculate the risk of a black swan event...?

<comment><USER37> I'd be more impressed with Taleb if he published the results for his Emperica fund for years other than 2008. Taleb's strategy was to buy options way out of the money. In boring years, the fund lost money. It did really well in 2008. Not enough numbers have been published to determine if his strategy was a net win over a business cycle. The win seems to have coming from the fund's short lifetime including 2008.

<comment><USER38> You only need to win once. One of his big things is about optionality and anti-fragility. If you buy something that barely hurts you in terms of cost, but can sky rocket massively if something big happens, you can capitalize on it, and all other costs were meaningless. Even VCs try for that, although with numbers that aren't nearly as good.

What do you mean by a business cycle? If his fund just goes until it makes it big and then he stops, is that not a business cycle? Did he continue? I don't know. It just seems weird to ask about a business cycle in the case of a strategy that is very long played, waiting for unpredictable results. The only thing that matters is can you play long enough to hit that result if that is your game? It seems clear that it did win, or else he'd probably be focusing more on it until he did? It's not like a regular business with actual output or production that can be easily replicated and measured, it's just a play till you win or lose deal and I'm sure there are others that did similar things and lost, just like many more companies are dead than alive and we only see the alive ones.

I understand wanting to see the numbers, but this is just one sample for a strategy.

</comment></comment></comment><comment><USER39> I'm infuriated that the author would allege that Taleb has a better way to do this but just links to a highly technical paper instead of addressing it.

</comment><comment><USER4> I think the difference in opinion is caused by Taleb modelling the election as though all of the uncertainty is caused by the fact that people might change their minds, whereas Silver is also including the uncertainty from polling errors.

Silver's predictions fluctuate a lot as time passes. Taleb is assuming that all of these fluctuations are caused by the electorate changing who they're going to vote for. Then he says "if you knew people's opinions were as volatile as this, you shouldn't have been so confident earlier!", or words to that effect. If lots of people will change their minds, then early polling won't be very informative about the final result.

But the fluctuations in Silver's predictions are actually caused by his changing certainty about how accurate the polls are. Silver does take into account that people might change their minds, but this isn't the cause of most changes in his predictions. So people actually change their minds a lot less often than Taleb's model of Silver's model suggests. This is why Silver can make strong predictions early on.

</comment><comment><USER40> The difference between epistemic and aleatory uncertainty is not well understood even in the machine learning world. Most applications of machine learning to domains where uncertainty needs to be quantified use aleatory uncertainty, when epistemic uncertainty is the right one. I wish we had better ways to explain these concepts, and perhaps better terms too. Alternatives like intrinsic/extrinsic or irreducible/reducible don't really work either, because they make it seem like it's a dichotomy.

<comment><USER19> I haven't read any of his works but I have a suspicion that Judea Pearl writes about causality in this niche with that inferential difference in mind.

</comment></comment><comment><USER41> I'm profoundly confused by the deep respect Taleb commands in the eyes of many people here, apparently. The guy has a few good ideas that he repeats ad nauseam, but he punches way over his own intellectual weight too often. A few especially egregious examples are his deranged GMO hate "paper" which is profoundly ignorant of the involved biology [1], his support of Syrian government's slaughter of civilians [2][3], and his Putinversteher views ([4] reads as a parody for anyone knowing anything about Putin and modern Russia). Combined with his unlimited arrogance, I don't understand how people can respect him intellectually.

[1]: [http://www.fooledbyrandomness.com/pp2](http://www.fooledbyrandomness.com/pp2)

[2]: [https://medium.com/opacity/the-syrian-war-condensed-a- more-r...](https://medium.com/opacity/the-syrian-war-condensed-a-more- rigorous-way-to-look-at-the-conflict-f841404c3b1d)

[3]: [https://medium.com/@ameraidi/nassim-taleb-is-wrong-on- syria-...](https://medium.com/@ameraidi/nassim-taleb-is-wrong-on- syria-e1faa523824c)

[4]: [https://twitter.com/nntaleb/status/773323163509850112](https://twitter.com/nntaleb/status/773323163509850112)

</comment><comment><USER42> Re: the desire to choose a 50% (or other) decision threshold.

It doesn't have to be a binary choice. Knowing the distinction between 65% and 80% improves your betmaking capabilities by allowing you to hedge, in some cases guaranteeing a profit [1] regardless of the odds and how they change.

[1] [https://help.smarkets.com/hc/en- gb/articles/115001431011-How...](https://help.smarkets.com/hc/en- gb/articles/115001431011-How-to-calculate-a-hedge-bet)

</comment><comment><USER43> Taleb's biggest thing is exposing holes in predictive models. Silver's biggest thing is making and using predictive models. So it's only natural for these two to quarrel.

</comment><comment><USER44> Of course the US elections are not as accurately predictable as e.g. German ones, or sports events. Not simply due to different pollster sources and their data quality (which Nate Silver tries to account for).

The biggest and most unpredictable factor in US (and British) elections is their winner-takes-all system, with the second layer of the Electoral College in the US which does not account for popular votes either.

</comment><comment><USER32> So does Taleb propose a better betting strategy? I'd like to see him put his money where is mouth is, rather than just his reputation.

</comment><comment><USER45> I would love to see the Nate Silver point by point response to this post. I think it would be humorous, but also add some insights into his proprietary black box.

I listen to the 538 podcast every episode, and I think I agree with cm2012 that this is a case of mixing up the "nowcast" with the actual forecast.

</comment><comment><USER46> The author doesn't seem to understand how the 538 model works. The 538 model _does_ take epistemic uncertainty into account; it just doesn't call it that. The model calls it "likelihood of polls moving by X% between now and election day". In 2016 they offered a "now-cast" which didn't include that, and answer the question "based on where the polls are right now, how likely is any given outcome if the election were held today?" while the "classic" model answered the question "based on where the polls are right now _and the fact that unanticipated things will happen between now and the election_ , how likely is any given outcome?". For 2018, they dropped the "now-cast", because people didn't understand what it was saying.

True, the epistemic uncertainty is limited -- it's based on past elections, because hey, 538 works with actual data. One could argue that rather than saying "71.4% Clinton 28.6% Trump", a better model would have said "71.3% Clinton 28.4% Trump 0.2% Election is cancelled due to nuclear war / natural disaster / etc" but I don't think anyone sensible is interpreting the model as excluding such extreme outcomes.

</comment><comment><USER47> I thought that the post was fairly unclear, but for me, it seems like the main argument against 538 is that it makes unfalsifiable claims about the probability of individual elections - picking a winner is a falsifiable claim, but assigning a probability always allows Silver to claim something like "even events with a 10% probability occur frequently" even if his model assigns a high likelihood of victory to the loser of an election.

My favorite Nate Bronze takedown remains Carl Diggler[1].

[1] [https://www.washingtonpost.com/amphtml/posteverything/wp/201...](https://www.washingtonpost.com/amphtml/posteverything/wp/2016/05/09/our- fictional-pundit-predicted-more-correct-primary-results-than-nate-silver-did/)

</comment><comment><USER48> Five thirty eight is pretty consistent with saying their forecasts more than a few days out are unreliable. They're fairly accurate with with their final forecasts, though.

</comment><comment><USER49> You could use the Brier score to compare how good various forecasters are at predicting something

</comment><comment><USER50> As a non-specialist, I like how the discussion boils down the picture at the end: [https://cdn-images-1.medium.com/max/1600/1*D_tidaT- fHMY3DRLg...](https://cdn-images-1.medium.com/max/1600/1*D_tidaT- fHMY3DRLgjwekw.png) in that it is something I can understand.

<comment><USER20> Nate Silver always calls the nowcast (blue line) for what it is - a forecast for if the election was held that day. The forecast, made a few days before election day, is the official forecast and the one that beats most other estimates.

<comment><USER4> That blue line is a record of Silver's forecast, not the nowcast. You can compare them here [https://projects.fivethirtyeight.com/2016-election- forecast/](https://projects.fivethirtyeight.com/2016-election-forecast/)

</comment></comment></comment><comment><USER51> Why does this not just link to the Twitter war?

</comment><comment><USER21> I've been following this spat since it reignited several weeks ago, but also since Taleb first attacked Nate on Twitter back before the 2016 elections, and it has been the final nail in the coffin as to any supposed credibility Taleb commands.

The quandary that FiveThirtyEight and Silver are in is that the general public is stupendously bad with probabilities. Prior to the the 2016 election, Silver was personally being attacked, in some cases by major media organizations like the Huffington Post, and accused of tipping the scales towards Trump (for some inexplicable reason), since their models were giving him approximately a 1 in 4 chance of winning, since everyone _knew_ it was a certainty Clinton would win. Then, in the months following the election, the narrative somehow switched, and the fact that Trump won despite only being given a 1 in 4 chance by FiveThirtyEight meant that Silver was now a hack and the model was wrong. This same criticism has been leveled by many right-wing media personalities, who had been trotting out Silver's 2016 predictions leading up to the election, as well as by the New York Times, whose own models were giving Clinton nearly a 90% chance of victory.

So now, fast forward to this year's election, Silver is doing his best to drill into people's minds that, yes, their model showed a Democratic win in the house as the most likely outcome, but that absolutely doesn't not mean their model says it is an absolute certainty, or that other outcomes would be unusual. It isn't covering his ass, its educating the public on how probabilistic statements work.

This is something Taleb _should_ know. But Taleb has proven himself to be a hack and an intellectual parasite. He hasn't actually produced any ideas worth discussing since "Fooled By Randomness" which was nearly 20 years ago. Basically all of his works since then have been rehashing the same idea, or, as with Skin in the Game, pseudo-intellectual ramblings containing little to no interesting ideas, and what ideas do exist have been rehashed a million times by others.

Since then, he has taken to making ad-hominem attacks and nonsensical critiques on others in the public view, often on Twitter. I hate bringing up Trump, as it happens far too often in discussions these days, but some of his methods of "debate" are strikingly similar: strange monikers ("klueless Nate"), schizophrenic jumps between topics/arguments, often indecipherable language, and a ridiculous volume of output. All of this combines to mask the fact that most of the time, he isn't _actually_ saying anything, or at least anything sensible, but by shouting loud enough, long enough, and purposefully making his point difficult to identify, it almost becomes impossible to argue with him, and a non-insignificant number of people will assume he is right.

Interestingly, I've also found many of his supporters to be similar to some of Trump's or other figures such as Musk. There is a cult of personality built up there where they have established the person as a visionary first, and therefore anything and everything they do or say is correct. Many of them parrot back the same, shallow catchphrases of his, that rarely contain anything insightful but are general enough that they can be thrown out in any situation: critics or dissidents are "Intellectual yet Idiots" or don't have "Skin in the Game". Note that the arguments of these critics or dissidents are almost never addressed.

Unfortunately, the spat between Taleb and Silver (which actually started back prior to the 2016 elections), is exhibit A in why Taleb is an intellectual charlatan, and shouldn't be given the time of day. Silver isn't some perfect person either, but in general he has been a reliable voice in the realms of political prediction, fairly forthcoming on shortfalls, and his most damning criticisms all seem to be built upon critical failures in the understanding of probability, or a willful misrepresentation of his results.

</comment><comment><USER52> No one should care about anything that happens on Twitter. It's that simple.

</comment><comment><USER53> [https://www.theguardian.com/books/2018/feb/25/skin-in-the- ga...](https://www.theguardian.com/books/2018/feb/25/skin-in-the-game-by- nassim-nicholas-taleb-digested-read)

</comment><comment><USER54> The whole 2016 situation feels like many people are borderlining on delusion, Nate included. The Comey thing certainly helped Trump, but even _the day of the election_ 538 was still forecasting a massive win for Hilary. How can the probabilities be that wrong?

Because the polls were wrong. Or, at least, incomplete. It doesn't matter how good your algorithms are if the data isn't there. And 2016 proved that 538, and really most media outlets, don't have a grip on America.

In other words, the existence of a black swan event in that particular system didn't really matter.

Silver is a glorified modern fortune teller, who seems to have deluded himself into thinking that simply having data means you can prescribe meaningful probabilities to the future. Assigning probabilities to a coin flip is easy. Figuring out the most likely winner of a game of baseball is a little harder; there's a whole movie about a guy who was basically doing that in 2002. Politics is a completely different field. You can't possibly assemble all of the data necessary to be remotely confident in the probability of outcomes. And let's not forget unpredictable black swan events.

But the readers love it. And, especially during the elections, the media would bring him out like a golden boy computer whiz, because he was saying the same things they were, but he's really smart and has the data and magic algorithms to back him up. And he was right that one time 8 years ago. He's about as pointless as Sean Hannity, with the one exception that, at least recently, Hannity was actually more correct about the future than Nate. It doesn't matter if you are right or wrong, if the reasons are wrong.

<comment><USER15> > but even the day of the election 538 was still forecasting a massive win for > Hilary

It was predicting a large electoral win as the median scenario, but only a 70% chance of Clinton winning at all, because discrepancy between actual outcomes and polling were likely to be correlated across states, and many states were very close. This is where Silver differed from the other forecasts that were saying Clinton 90%+ based on the (historically false) idea that differences between votes and polls were independent across states.

> You can't possibly assemble all of the data necessary to be remotely > confident in the probability of outcomes.

You often can be more than remotely confident, but it's true that the national result of the 2016 Presidential election wasn't one of those times. OTOH, Silver's forecast reflected that, since ~70% is extremely low confidence.

<comment><USER9> FiveThirtyEight also predicted a 10% chance that Clinton would win the popular vote while Trump won the electoral college.</comment></comment></comment>


Ask HN: Anyone above 30-35 applied to YC? - <AUTHOR> Probably not that much about the age but more about the people with the kids/other family responsibilities, how did you guys plan to go to CA for 6 months with the dependents staying back there? Any success stories? Assuming you are accepted, how did you manage the next six months? I am a bit cautious about it all and not sure I could leave my family (wife and kids) as we don't have grandparents to help us and with the small kids it is a lot of work... Even if you didn't make it to YC, or never tried (but planned), what was the plan? Thanks!!! <comment><USER2> I have lived apart from my family before for extended periods of time. In my case my ex-wife was never supportive of risk taking. I totally got where she was coming from too. However, we needed a roof over our heads and food and 3 kids.

In the end, it resulted in divorce. Now my once 7 year old is in college with 2 others headed there very soon.

I missed most of their lives to be honest. When you get divorced things can be messy and you have to schedule visits and as the kids get older they may want to be with friends instead on the weekends.

I have regrets. I also enjoyed what I was doing. Now, I do wonder if I should have had a 9-5 and how my life would have played out differently.

I'm not saying this will happen to you, but there can be an ugly side to relationships when you are working so hard and your family just wants you to sit and watch a movie with some popcorn and you feel like you can't. There is always work to be done.

</comment><comment><USER3> If I'm not mistaken the program duration is 3 months (not 6), so still challenging if you have a family but surely doable if you have the support of your partner.

Personally I think it's funny (no offense intended) to think that people are too old to start a company / startup beyond 35. I think the average age of founders is actually slightly above that and I would argue that the success rate of experienced founders should also be higher as those people usually have more experience and connections. So don't get infected by the ageism that you'll often see on HN, you can totally do it. Also please remember that there are many different ways to build a successful company, so don't think the "crunch mode" model that most single founders in their 20s use is the only one.

<comment><USER4> One thing to note is that while YC is 3 months, most founders spend at least another month or two fundraising after that, which can be as grueling as YC is, so it probably does make sense to think of it as closer to a 6 month commitment in the Bay Area than 3.

</comment></comment><comment><USER5> I applied several times, and I do have a family. I have never considered it risky financially, for several reasons, mostly because get some 100k from YC, even if you are 2 or 3 founders, that will cover your costs for 3-6 months.

If your family don't support you going to SF after getting accepted into the best accelerator in the world, they won't be supportive of your startup in general.

Of course being away from the family can be tough, but considering that the chance of succeeding once you get in is so high, it should not be too hard to convince them that it's a good idea. It's also so much easier to focus on work if you are far away. I sometimes go away for a week so I can really focus, without feeling streesed about staying late at the office.

</comment><comment><USER6> Old man here (30's), co-founder was 29 at application time. Age didn't seem to come into it in our case! We got an interview with only an idea, and we received positive feedback from the partners. We weren't accepted at the time, though. YC (and other incubators) said they wanted a working prototype before investing.

That's tricky, since we're in biotech; we've had to do a lot of front-loaded grinding in order to bootstrap a molecular biology lab, but now we're getting close to presentable results. I suppose if it were easy, everyone would do it!

If we had been accepted, it would have been a rush, since co-founder was pregnant (baby is 2 yo old now!), but since we're married, it makes it easier to find synergy between work and family, heh. We have little man's grand parents right next door, and they've been a big help as we got rolling early on.

Could any YC alumni speak to the family issue? The program is pretty short, but there is space for YC teams and alumni to set up a babysitting ring/play group for people in this situation. How _did_ you guys handle pulling up stakes with your kids for a season? There are some googlable good outcomes, but I'd also be interested in hearing about the challenges as well.

<comment><USER7> Is 30 old? I work with enterprise architecture in the public sector of Scandinavia, sometimes on a national strategic level. It's rather rare for anyone under 30 to make valuable contributions. It's not unheard of, but it's rather rare.

Most people under 30 are only a few years into their careers, a few are only just finishing their degrees. On top of that, a good deal of people are starting families in their early thirties.

Maybe there is just a huge difference of culture, but to me it seem, that the prime years career wise seem to be between 45 and 65. It's a little different for startups and founders, where a lot of people start below 25, but the second most common age group in startups is above 55, with an average age around 45-50.

Data source: [https://entrepreneurblog.ey.com/2017/03/01/ivaerksaetterdanm...](https://entrepreneurblog.ey.com/2017/03/01/ivaerksaetterdanmark- i-tal-og-tendenser/)

</comment></comment><comment><USER8> I think first we need to make a differentiation of RESPONSABILITY and AGE.

Mr. Rocket Eletric Car Man Inventor has a few kids, wives whatever... but he doesn't take care of them, nor feel responsible, he is almost reaching his 50 but he lives like a 23 year old.

Age doesn't matter.

Now, if you feel responsible for your kids, your spouse, dog or whatever. I would go a step back and consider doing something as another HN member suggested "cash flow positive". Can be a business as well, consulting or this thing that some people seem to hate here, called "working for the boss". Don't buy the YC propaganda of success. Success can mean also taking care of your kids. Today is full of parents that think they are putting their kids ahead because they work a lot, but the only thing they are really doing is that they are putting their careers ahead. Well, not Today, this trend has been going on for a while and we've already seen how this affects children, or even adults...

<comment><USER5> The YC program is cash flow positive for you as an individual, that's the point...

Just fail fast and get back to your normal job, wiser and more experienced, and with a much improved CV.

</comment></comment><comment><USER9> I'll probably get downvoted for this, but I think it's really important for you and your family.

If you don't have a big safety net (college money for kids, many months of living expenses, emergency fund, etc.) then don't try to become a founder. You are almost guaranteed to fail (as all startups are). If your appetite for risk is low, don't do it.

There's a lot of confirmation bias on HN ("I have small kids and started a company, so can you!") but I've personally seen the other side of the coin, and it's very ugly.

<comment><USER4> If you can get into a good accelerator like YC, it's not _that_ risky. You'll have a good shot at raising more money after, and then worst case you have a couple years to work on something interesting under relatively financially comfortable (albeit stressful) conditions, learn a ton, and make a lot of valuable connections. Even if it doesn't pan out, your career prospects are likely to improve, not get worse.

That said, without finding a way to raise money or bootstrap to profitability, you're absolutely right.

<comment><USER5> If you can get into YC therer is really no risk at all for you.

1\. You have enough to cover your costs while in SF 2\. If you are good enough to get in, you will never have a hard time to get back into employment 3\. Having been accepted to YC will in fact boost your prospects afterwards.

Unless your situation at work is very unusual, there is no downside to getting accepted, only upside.

<comment><USER10> > 1\. You have enough to cover your costs while in SF

What about your costs back home? You need to earn enough to live in SF plus pay for your food and mortgage etc. at home for your family. You really need some savings.

<comment><USER5> Let's say you normally earn 120 k a year, or 10k a month. You and your cofounder share a studio in SF for 5k, then you need 10 + 10 + 5 = 25 k a month, meaning the YC money lasts you 4 months if you both had a good salary and don't want to compromise at all. If you are lucky enough to be earning more than 120 k now, then I'm sure you have 100+ stashed away by now, so it really should be a no-brainer for almost anyone.

In reality most people earn much less, and are willing to dial down their spending a bit for a few months, so I really don't think money is an issue for the vast majority of YC applicants.

<comment><USER10> The 100 stashed away is the issue though. Even if you have it, it might be rainy day money not for living expenses for a moonshot.</comment></comment></comment></comment></comment></comment>


Next wave of SaaS - <AUTHOR> http://www.laktek.com/2017/01/12/next-wave-of-saas <comment><USER2> Auth0's business model is a race to zero. Microsoft, Google, Salesforce, Oracle and others (for example Okta, Onelogin in the startup arena) are going to force their prices down to practically nothing. The per user pricing model in the identity space is loved by insipid venture capitalists who like simple "back of the envelope" math, but customers hate it. You are penalizing customers for using your service--rewarding them for putting as few users as possible in the system. Also, there is no one-size fits all value for users-- some users are more valuable then others (for example, an employee versus a one-time ecommerce customer who buys a t-shirt). So you end up trying to price users differently, which undermines your value story. What's more likely to happen is that open standards will increase competition and centralized service providers who add very little value, and are big targets for hackers, will be lucky to get out alive.

</comment><comment><USER3> You are an absolute visionary and could be the next Steve Jobs or Elon Musk even. Please keep sharing your predictions and I can stop my 401 contributions and invest in those companies you mention and beat Warrent Buffett soon.

</comment><comment><USER4> OK, this makes a better case than the previous post (HN discussion: [https://news.ycombinator.com/item?id=13371662](https://news.ycombinator.com/item?id=13371662)), as it is discussing new niches opening up rather than old/existing ones dying out.

</comment><comment><USER5> Can you please give an example for an automated action flow?

<comment><AUTHOR> Simple one is re-engagement notifications you can do with Mixpanel ([https://mixpanel.com/notifications/](https://mixpanel.com/notifications/))</comment></comment>


Are you a Greek company Blocked by capital controls? - <AUTHOR> http://zerofund.org

<comment><USER2> It looks like they stuck a line about Greek capital controls on top of a site for something else entirely. "Will it blend? Refine your idea, get feedback from users and iterate." "You need hosting/domains/ads? Click here." That last is the only clickable thing on that page other than "social" links, and it leads to a Google sign-in page.

WTF?

</comment><comment><USER3> This hit the news here in Greece a few days ago. It's an initiative from Greek start-ups in US that will act as a mediator to help pay costs like hosting and such since all Greek credit cards are blocked for the time being. I assume these companies have subsidiaries in Greece where they can receive the money in cash. It's a solidarity gesture and probably not a permanent one.

</comment><comment><USER4> I wonder how this is supposed to work, given that zerofund seems to be registered in the US (based off their WHOIS records)

</comment><comment><USER5> I would recommend to stay in contact with entrepreneurs from Argentina. They are very experienced in how to deal with situation like this (no banking, capital controls, etc). In particular, because the greek situation is still new, there are opportunities to do things well to protect your assets or to think strategically now: open a bank account in another country, just for backup purposes.

</comment><comment><USER6> What is actually being proposed here? Is this a charity effort? A vulture capital fund that wants equity? Something in between?

<comment><USER7> Populism?</comment></comment>


McDonald's will accept selfies as payment - <AUTHOR> http://www.dailydot.com/technology/mcdonalds-accepts-selfies-as-payment/

<comment><USER2> Given how often those Monopoly sets get completed (never) I am assuming this will be equally rare. It is one of the better promotions I've seen though - spend the advertising budget on free meals to customers, get shared like crazy through social media.</comment>


Show HN: A.I platform showing you what Elon Musk, Bill Gates and others read - <AUTHOR> http://www.whattheyread.xyz <comment><USER2> Awesome idea but a) would like to see it/try witbout signing up and b) try to find other people to follow because Musk, Gates, like HN, tend to read the same dry business/"self help" books. I'd like some novels/biography/etc books to read!

<comment><AUTHOR> Appreciate it! If you send me your email address/sign up I'd be happy to show you version one. Richard Branson's reading list, to your point, is far wider reaching than your typical self-help tech business book. He reads the type of fiction you probably know from when you grew up, mixed with articles from The New Yorker, Economist and other premium sources. What I'm trying to show is that these people have got to where they are because of their broad interests beyond the dry business books you described.</comment></comment>


Arthur's LISP in BASIC - <AUTHOR> http://www.cs.rit.edu/~anh/lisp_soft.html

<comment><USER2> I remember writing my own adventure game in Basic, but with only 8KB of RAM on my PET computer, I ran out of space after only 6 rooms.

Personally, I don't have a lot of nostalgia for those days. I have no idea how I ever persisted with such primitive tools. Looking at Arthur's Basic code just makes me feel bad, for both my and his former selves.

</comment><comment><USER3> I don't remember anywhere near enough basic to try answering my own question, but: BROKENHEART. What?

<comment><USER4> In SICP's stop-and-copy garbage collector that was the tag on a forwarding pointer from the from-space to the to-space. Since this was written after SICP 1st edition came out, I'd guess that's the source.

</comment></comment><comment><USER5> > That was a bug in Atari BASIC that I never tracked down.

Never assume it was a _bug_ in BASIC. A bug indicates it was a mistake. Very often code of that age had "tricks" to workaround hardware/limited resources that could be perceived as a bug when it kept something else from happening as intended, but it was required. That is the difference between a hacker then and one today- they didn't bitch and complain about bugs, they just made it work. I know you were coding back then- I was too, but I have a feeling you weren't well versed with the ins and outs of how BASIC interpreters of the time were written from reading things in your blog like:

"I'm not a programmer. Or a hardware guru. I've come to believe myself the amateur anthropologist. I like rummaging through the midden mound of the techpress reading what the tribespeople have to say. I'm bookish."

<comment><USER2> _> That is the difference between a hacker then and one today- they didn't bitch and complain about bugs, they just made it work._

Since I personally heard Sussman & Ableson bitch about how awful Basic was, I'll have to say that you are wrong in this regard.

Of course, they wouldn't have been bitching about the bugs _in_ Basic, per se. They would have been asserting that Basic _is_ a bug.

<comment><USER5> Basic is obviously not a bug. It is the reason many of us got started, and Atari Basic is no exception. My point was that people that speak of bugs of software, OS's, language interpreters, etc. of that time have no clue how difficult it was to write them get them to do all of the things they needed to do. Ridiculous I got downvoted for that. Pfft.</comment></comment></comment>


Smartphone-based earthquake alert system triggered by Mexican football fans - <AUTHOR> https://www.reuters.com/article/us-soccer-worldcup-ger-mex-mexico/mexicans-jubilant-over-world-cup-win-trigger-earthquake-sensors-idUSKBN1JD125 <comment><USER2> There's a lengthy explanation published in Facebook [1](in Spanish, sorry). The important fact is that there's an app which reads accelerometers in people's phones, which is used to trigger these "seek shelter" type alerts. Since many smartphones shook a lot in unison, the public alert was triggered. They apologize for this and state that they are working to avoid this from happening again.

However, they remark that actual, scientific seismographs _did_ indeed pick these "soccer goals" events, although since they were of relatively low magnitude (III to IV Mercalli scale), no public "seek shelter" alert was generated on the basis of these readings.

[1] [https://www.facebook.com/sismologia/posts/2149439968431910](https://www.facebook.com/sismologia/posts/2149439968431910)

<comment><USER3> Now it's time to compare these actual measurements with all that's written about "what would happen if all Chinese would jump at once."

<comment><USER4> [https://what-if.xkcd.com/8/](https://what-if.xkcd.com/8/)

<comment><USER5> The most insane part of that blog is that the entire world population would fit within the state of Rhode Island.

</comment></comment></comment></comment><comment><USER6> What If Everyone On Earth Jumped at Once?

Allain found that our jump would push on the Earth ever so slightly, giving it a recoil speed of 2.6 x 10^-13 m/s. That is, in one second, Earth would move about a hundredth of the radius of a single hydrogen atom .

[https://www.livescience.com/33383-everyone-on-earth- jumping-...](https://www.livescience.com/33383-everyone-on-earth-jumping-at- once.html)

<comment><USER7> would like to read XKCD response :)

<comment><USER8> Here you go: [https://what-if.xkcd.com/8/](https://what-if.xkcd.com/8/)

</comment></comment></comment><comment><USER9> Here's the tweet by the Institute of Geologic and Atmospheric Investigations in Mexico.

[https://twitter.com/SIMMSAmex/status/1008374780351967233](https://twitter.com/SIMMSAmex/status/1008374780351967233)

</comment><comment><USER10> Mexico City was built on a lake. I wonder if that makes it more susceptible to such man-made earthquakes?

<comment><USER11> Perhaps, but that's irrelevant in this case; there was no tremor. The alert was falsely set off by people's phone apps.

<comment><USER12> That's not entirely true - "proper" detectors did detect a "tremor".

[https://www.nytimes.com/2018/06/17/world/americas/mexico- soc...](https://www.nytimes.com/2018/06/17/world/americas/mexico-soccer-world- cup.html)

</comment></comment></comment><comment><USER13> My mom warned me to diet.

</comment><comment><USER14> lol nope. not unless the sensors were buried less than a foot underground under a really big crowd.

<comment><USER15> Well actually it happened recently in Peru:

[https://twitter.com/alerta_sismo/status/930989560896647169](https://twitter.com/alerta_sismo/status/930989560896647169)

So either someone saw that and decided to make this story up, or it does indeed happen.

I can tell you from experience that seismometers are ridiculously sensitive- the noise reductions that need to be done after shooting a land survey are a nightmare.</comment></comment>