The 'Undue Weight' of Truth on Wikipedia - <AUTHOR> http://chronicle.com/article/The-Undue-Weight-of-Truth-on/130704/ <comment><USER3> I think the overall problem is that wikipedia attempts to substitute policy for expertise.

As other have pointed out, wikipedia has to deal with lots of bad edits from people who are not motivated by a pursuit of facts or truth.

To deal with this, they've come up with a set of policies that the editors seem to enforce fairly rigidly. This does an okay job of preventing the wackos from taking over. Unfortunately, since the editors often lack the subject expertise to distinguish cranks from experts, these policies end up making it harder for experts to contribute in some cases.

<comment><USER4> It is indeed very annoying for experts to contribute to Wikipedia. They probably shouldn't. Instead, they should do what experts do best, and Wikipedia should do what encyclopedias do best: to wit, experts should conduct research to generate new primary sources or write books to generate new secondary sources, and Wikipedia should continue finding secondary sources to summarize.

<comment><USER5> That seems like a real shame, and an unnecessary repetition of work. Surely there's some way to verify expertise and provide expert commentary _with supporting links to primary sources_ , even if it doesn't mean editing the entry directly? Perhaps a side-bar?

I'm sure this would lead to arguments about how to verify expertise, but even if it only started with unimpeachable credentials that would seem like a start. Tell me very clearly who is providing the commentary, and I can decide myself if it's credible.

I feel like I'm rambling a bit, but really this seems like a wasted opportunity. Why recreate Wikipedia from whole cloth when it already has so much? I suppose that given the way it's licensed, you could always fork it...

<comment><USER4> An encyclopedia is a survey of existing secondary sources. It's not a research venue.

The _true_ waste would be taking valuable research and synthesize and _hiding_ it in an encyclopedia. Pokemon aside, most new knowledge that merits inclusion in Wikipedia deserves its own independent source.

It goes research -> authorship of secondary source (journal article, book, magazine article, whatever) -> citation in encyclopedia.

And that's really all that happened here: someone tried to skip the middle step (notably: they tried to skip it _while authoring the secondary source_ \--- the author of this article published an authoritative text on the Haymarket Riot later on), and Wikipedia called that out.

<comment><USER5> > An encyclopedia is a survey of existing secondary sources. It's not a > research venue.

Then I suppose I'm also frustrated at Wikipedia's lack of ambition. To strive toward that benchmark and not past it seems, as I said, wasteful.

One of the things that fuels this feeling for me is the work of people like Carl Sagan and Neil deGrasse Tyson. I think there is a role for experts to address the public directly, rather than their peers. To be sure, it can get very messy, as some of the most vocal cranks think they are experts and seek every possible venue to espouse their nonsense, _but they do that anyway_. I'd love to see the bar lowered for scientists to contribute to works that are easy to access via the web and written for a lay audience, without having to start and maintain their own blog.

<comment><USER4> Experts _should_ address the public directly. It has never been easier for them to do that. But they shouldn't address the public by writing encyclopedia articles. They should write books, write journal articles, give recorded talks, have IamA discussions on Reddit, debate things on message boards. Encyclopedia articles are the worst way for them to address the public.

Wikipedia is one of the most ambitious projects on the whole Internet. It is the world's most ambitious and most expansive encyclopedia. It was created entirely out of donated time using the Internet. It is hard to take seriously any argument that says Wikipedia is unambitious.

There's a whole rest of the Internet for you to build other ambitious knowledge projects on; the rest of the Internet also doesn't demand that you redefine the concept of an encyclopedia to do it.

<comment><USER6> "An encyclopedia is a survey of existing secondary sources"

This is incorrect. The definition of encyclopedia has nothing to do with 1) primary vs. secondary sources, nor 2) a survey of said sources. Consider "The On-Line Encyclopedia of Integer Sequences", which contains links to primary sources. Consider the "Encyclopedia of Physics", which is certainly not a review of existing secondary sources. The "Encyclopedia of Science Fiction" (from the 1970s) contains new research and essays about the people and themes in science fiction.

"Encyclopedia articles are the worst way for them to address the public."

When one of the first things that the public does is to consult Wikipedia, then a Wikipedia page is one of the best ways to reach people. If the information on the page conflicts with the primary sources, then the weight of the secondary sources should be diminished in favor of the secondary sources which are in agreement with the primary sources.

Your statement here is also wrong even on the surface. Stephen Barr (to pick one of many specific examples) is a researcher on grand unified theories, and he contributed the article on grand unified theories to the Encyclopedia of Physics. You saw elsewhere in this thread that Mandelbrot contributed the "fractal" article to Encarta. The Wikipedia page for "Encyclopædia Britannica" even says "Britannica's authors have included authorities such as Albert Einstein, Marie Curie, and Leon Trotsky".

Why would he or the other expert contributors have done that if doing so is the "worst" way to reach the public?

The obvious conclusion is that your views of how encyclopedias work is wrong, in that it does not agree with numerous real-world examples. Hence it is you who have redefined "the concept of an encyclopedia."

<comment><USER4> What are some examples of original research published in the Encyclopedia of Physics? What's an example of something documented in the Encyclopedia of Physics that isn't traceable to some earlier publication in something like Physical Review Letters?

I think you've missed my point with regards to experts writing in encyclopedias. I didn't say they _can't_ ; I said they probably _shouldn't_ , as it's a waste of their time. Of course, if Britannica is paying you to, different story.

<comment><USER6> There are three issues here: primary sources, secondary sources, and original research. You said "An encyclopedia is a survey of existing secondary sources". It is not. An encyclopedia also contains references to primary sources, and can also contain new research.

A reference to a primary source would be, for example, a reference to Newton's "Philosophiæ Naturalis Principia Mathematica" or to Darwin's "On the Origin of Species". An article on the history of evolutionary thought would be remiss if it does not include Darwin's book and instead only referred to books discussing Darwin's work. Like the children's game "telephone", only relying on secondary (and then tertiary, then quaternary) sources can amplify noise.

You then asked about "examples of original research published in the Encyclopedia of Physics". There are two different types of research involved here. One is "original to the field of physics". Physics has a well- established mechanism for publishing and disseminating work, and that is not an encyclopedia.

The other is the research needed to reconcile and synthesize multiple viewpoints into a well-constructed whole. A non-fiction piece for the New Yorker likely entails new research (even an interview is new research), and that's the type of research which goes well with an encyclopedia. Take a look at Wikipedia's entry for "History of the Encyclopædia Britannica" with comments like "40,000-word hagiographic biography of George Washington" and "Dr. Thomas Thomson, who introduced the first usage of chemical symbols in the 1801 supplement". Thomas Young translated the Rosetta Stone and in his WP page is written "[s]ome of Young's conclusions appeared in the famous article "Egypt" he wrote for the 1818 edition of the Encyclopædia Britannica."

Or take Asimov's Biographical Encyclopedia of Science and Technology. The entire encyclopedia was written by Asimov, who commented "I alone have done every bit of the necessary research and writing; and without any assistance whatever, not even that of a typist." Right there in the text it says "research."

Do you think these examples of the research which goes into encyclopedia articles aren't actual research? If not, why not? Or are these simply not encyclopedias?

As to "if Britannica is paying"... do you think Harry Houdini, Albert Einstein, Marie Curie, Sigmund Freud, Henry Ford, Leon Trotsky, Arthur Eddington, Lord Kelvin, Humphry Davy, John Stuart Mill, Thomas Malthus, and yes, even Isaac Newton, were contributors to EB mostly because they were being paid for their work? Most certainly not! (How much would Ford's time cost?) From what I've read, other factors were because they wanted to contribute to a collection of knowledge, and because of the prestige.

<comment><USER4> I think you're providing a lot of examples of things that Wikipedia is also largely fine with.

Meanwhile, the author of this article did _original research_ , generating knowledge that was not only new to the field but that actually contradicted the field's best known sources.

Wikipedia (justifiably, but not particularly gracefully) told him "go write a journal article and then come back and cite it". Which is what he did.

This makes sense for a variety of reasons, some of them having to do with the charter of an encyclopedia, others simply as a matter of pragmatism: 9 times out of 10, when someone contributes original research to Wikipedia, their work is crazy.

<comment><USER6> Wikipedia must be fine with it because many of the 1911 Encyclopedia Britannica articles (which had entered the public domain) were imported into Wikipedia pages.

My point though was nothing to do with Wikipedia's policies. It was to your incorrect definition of what it means to be an encyclopedia. You've said:

\- "Wikipedia is an encyclopedia. It's a terrible place for original research." I showed several examples of original research done for encyclopedias. One was the first use of the element symbols now used in every chemistry book.

\- "everyone's understanding of what an encyclopedia (ANY encyclopedia) is" ... "is not a place of first publication for new research findings." In addition to the previous comment, this view falsely separates the scholarly research which goes into producing an encyclopedia from the scholarly research of any other field.

\- "Wikipedia should do what encyclopedias do best: to wit, experts should conduct research to generate new primary sources or write books to generate new secondary sources." I gave a long list of encyclopedia articles across several encyclopedias written by acknowledged experts on the specific topic. Traditional encyclopedias often ask experts to do this. Wikipedia is in the small minority.

\- "An encyclopedia is a survey of existing secondary sources". I gave many examples where encyclopedias references the primary sources, and pointed to encyclopedia articles which are not a survey of existing sources.

\- "[Experts] shouldn't address the public by writing encyclopedia articles". Excepting that experts _do_ address the public by writing encyclopedia article, and have been for centuries.

\- "Encyclopedia articles are the worst way for them to address the public." Excepting as Wikipedia shows, encyclopedias are often one of the first places people turn to for information, so it's a very _good_ way to address the public.

\- "Experts shouldn't want to write encyclopedias." Except that some encyclopedias are written by experts. Do you think the "Encyclopedia of Magnetic Resonance" was written by non-experts? (Hint: "The existence of this large number of articles, written by experts in various fields, is enabling the publication of a series of EMR Handbooks on specific areas of NMR and MRI.")

Your statements are definitely contra-factual to how other encyclopedias work, as you make statements for which counter-examples are easily found. Your understanding of the goals and purpose of an encyclopedia seem based solely on your understanding of the goals, purpose, and operation of Wikipedia.

Do you have any evidence to back your claims? Otherwise I must conclude that you don't know what you are talking about.

<comment><USER4> From what I can tell, the only encyclopedia you have that really refutes my argument is an encyclopedia of science fiction. When I asked you to pin down what original research the Encyclopedia of Physics hosts, you provided examples of things that are also fine on Wikipedia.

<comment><USER6> How bizarre. The one claim of your which I mostly agree with is that there are better ways to disseminate new scientific research than through an encyclopedia. Yet this is the one you insist on bringing up again.

What I say is that original scholarly work includes developing new synthesis of how to interpret existing information. This new work definitely has a place in (some) encyclopedias.

Ha! I just looked up the Wikipedia article on "Encyclopedia." It agrees with me, saying "The second half of the 20th century also saw the publication of several encyclopedias that were notable for synthesizing important topics in specific fields, often by means of new works authored by significant researchers."

That directly and explicitly counters your argument that encyclopedias categorically do not have original content.

</comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER7> Looking at the Talk page itself ([http://en.wikipedia.org/w/index.php?title=Talk:Haymarket_aff...](http://en.wikipedia.org/w/index.php?title=Talk:Haymarket_affair&diff=prev&oldid=265741836), at the bottom, thanks zqfm), it was not clear to me reading his Chronicle article that he did not cite the primary sources _in Wikipedia_. Rather, in Wikipedia, he cites his own blog post, and in that blog post, he cites primary sources.

As ZeroGravitas points out, consider the case of a crank who links to his own blog as a source, and that blog post cites primary evidence. The Wikipedia editors now have a job that is identical to academic peer-review. I don't think that should be their job.

<comment><USER8> _The Wikipedia editors now have a job that is identical to academic peer- review. I don't think that should be their job._

Then why have editors? God forbid that, if you take on the mantle of vetting articles, you actually exert some intellectual _effort_.

<comment><USER7> Because now Wikipedia editors are required to have the same expertise in each subject as academics who spend their careers in those subjects. I submit that model is clearly not sustainable, and quite different from not expecting them to expend intellectual effort.

Wikipedia is not a place for original research for exactly this reason. Once something has gone through peer review, and is published somewhere, then it can be used in Wikipedia. I think that's reasonable. Wikipedia editors are then relying on a particular subject's community of experts instead of having to be those experts themselves.

I think it's also important to note that this model is the same as any other encyclopedia.

<comment><USER8> Wikipedia would seem like a great place for original research, right?

It's trivial to get people to check over claims, and you have a place to discuss issues (Talk pages), and the person doing the research can cite their references _right there_ and get called out on it if they don't.

<comment><USER4> No, _the Internet_ is a great place for original research. _Wikis_ are great places for original research.

Wikipedia is an encyclopedia. It's a terrible place for original research.

</comment></comment></comment></comment></comment><comment><USER9> This follows the standard format of these complaints. If you read through it believing the author is a true expert then it seems like Wikipedia is crazy. If you read through it believing the author is a crank, then Wikipedia is doing a fine job.

I'm not even sure the guy isn't a crank, but if he isn't he needs to understand that Wikipedia needs a system that takes cranks into account. If he's simply a false positive on the crank detector because it turns out that _everyone else_ is actually wrong about this historical event then he'd have to demonstrate that the cost of false positives outweigh the good to effect a change, not just go in a huff because his pet subject isn't presented in the way he would like in Wikipedia.

<comment><USER10> Quote: "as I had cited the documents that proved my point, including verbatim testimony from the trial published online by the Library of Congress"

His opinion in this matter isn't as relevant as the fact that he cited actual testimony. That alone should lend enough weight to the edit that it should not have been reverted simply b/c of the Wikipedia "undue weight" policy.

<comment><USER11> Evaluating primary sources isn't a perfectly simple and straightforward exercise, and cranks generally have facts that they can point to to "prove" that their view. I expect that with selective enough citation I could create a fairly convincing (to a layman) argument for quite a wide variety of points of view.

<comment><USER12> Comparing primary sources is indeed not straightforward, but this is primary vs. secondary. If a book makes a claim that is directly contradicted by _the author's own source_ then not much expertise is required to see that preferring the "child" over the "parent" would be absurd.

</comment></comment></comment></comment><comment><USER13> This is _exactly_ how Wikipedia is supposed to work.

If you come up with a new theory that disagrees with scholarly/scientific consensus, an _encyclopedia_ is not the place to publish it. You publish it in a journal; if it _becomes_ a consensus, or at least generates significant serious response in that community, _then_ it will be documented in an encyclopedia.

If every single crank theory was accepted into Wikipedia, you'd have a wiki consisting entirely of holocaust denialism, homeopathy, Electric Universe, and woo-peddling. Wikipedia is not in the business of deciding what's true and what isn't; that's what the academic community is for.

<comment><USER14> Is there a specific reason you assume the academic community is doing a good job at this?

Consider the case in point. The myth the Chronicle author was refuting was a political myth: that the Haymarket defendants were innocent men railroaded by a biased prosecutor who was not "credible." This myth had been repeated by generations of pro-labor historians with a big ol' axe to grind.

As for the anti-labor historians? Oh wait, there aren't any anti-labor historians. At least, if by "historian" you mean "individual funded by the US Government to teach history." Thus, Wikipedia is simply recording in its pages the depressing result of a political power struggle in academia.

Now that labor has become the establishment, an honest historian who is not pro or anti labor, just interested in the past, can discover from primary sources that gee whiz, the prosecution actually had a case. It's 2012 so he won't be purged for this. On the other hand, it's not clear how he's supposed to purge all his axe-grinding colleagues who continue insisting that the sky is green.

Academia is just a thing called "academia." Science is just a thing called "science." The Soviet Union had both. Ours are better than the Soviet Union's, but they're still de facto government agencies. Jeebus didn't come down yesterday and make our government systematically infallible.

Imagine Wikipedia in the Soviet Union. Would you want it to be a crowdsourced version of the Great Soviet Encylopedia? Or would you want it to do a little better?

Wikipedia has done a great job of being a tertiary source, mostly. That doesn't mean it can't have higher ambitions for the future. When I stop being a child, I put aside childish things. It's childish to assume that "reliable sources" are reliable just because everyone says they are. Is Wikipedia all grown up now? If so, maybe it should at least think about starting to address its utterly circular definition of a reliable source.

If there is no conceivable mechanism to distinguish between homeopathy and medicine, how do our existing mechanisms work? Are these mechanisms unique? Are they perfect? Can they be duplicated, improved, advanced?

<comment><USER15> I think the really important point here is that _readers_ need to understand that an encyclopedia is a record of academic consensus rather than a compendium of solid facts. The former is a useful but imperfect tool. The latter is an impossible ideal to strive for which will inevitably result in something less reliable than the former.

</comment></comment></comment><comment><USER16> He left out the part where the editor said "I think we probably need to take another look at Schaack as you suggest. I, too, hope we can incorporate your insights into the article. That's why I'm going to read your book."

From <http://en.wikipedia.org/wiki/User_talk:MesserKruse>

</comment><comment><USER17> If you think of Wikipedia as a summary of what old-school mass media says about a subject, rather than being the truth or complete or informative or useful, then all these contradictions disappear.

<comment><USER18> Being the truth? I bet you can find an "expert" like the person complaining on the Cronicle, who disagrees whole heartedly about what you belive the "truth" is.

Outside of the hard science "truth" is a very negotiable subject. Just imagine how difficult it would become to find the "truth" between the opposing parties around the currently most popular The Cronicle article ( [http://chronicle.com/article/Charles-Murray-Author-of- The/13...](http://chronicle.com/article/Charles-Murray-Author-of-The/130722/) ).

</comment></comment><comment><USER19> Start pulling the string on this, and it looks like there's a potentially borderline admin, Gwen Gale,(1-3) at the heart of this, and the Chronicle article is just what boiled over into the slightly more real world of academia. It appears the bureaucrats at the Foundation have take notice.(4) I'm a little disappointed they haven't caught onto the involvement of the admin in question, and especially by Tim Starling's somewhat euphemistic allusion to the problem as "inertia".

This "inertia" is nicely described by the histogram of new admins. Those who seized power in the middle of the last decade are running with it. (5)

(1) <http://gwen-gale-heidi-wyss-tinpot-auteur.blogspot.com/>

(2) <http://english.sxu.edu/sites/kirstein/archives/1443>

(3) <http://en.wikipedia.org/wiki/User_talk:Gwen_Gale>

(4) <http://www.gossamer-threads.com/lists/wiki/foundation/271257>

(5) [http://en.wikipedia.org/wiki/Wikipedia:Successful_requests_f...](http://en.wikipedia.org/wiki/Wikipedia:Successful_requests_for_adminship)

<comment><USER7> I really want to avoid falling down this rabbit hole, but sources 1 and 2 pinged my crackpot-detector. That doesn't mean they necessarily are, but I am not willing to accept the notion, at face value, that Gwen Gale is the problem.

<comment><USER19> You're right. I should have just linked to the google search. <https://www.google.com/search?q=gwen+gale>

</comment></comment></comment><comment><USER4> Worth noting: the Haymarket Riot article on Wikipedia is a designated "Good Article". "GA" is a big deal. It's been on the front page of the site. Among other things, that implies that there are people specifically watching that article; changes to it can reasonably expect more scrutiny.

<comment><USER20> You're thinking of "Featured Article" - those get onto the front page.

It is a bit of an odd process but, basically, "Good Article" consists of a semi-formal review of the article by an uninvolved editor to assess it for neutrality, completeness and language (etc.).

"Featured Article" is a more involved formal review involving multiple editors. It's those that get then picked for appearance on the main page.

The intended progression for an article is supposed to be something like: Peer Review, Good Article review, Featured Article review.

<comment><USER4> I know about GA & FA, and that FA is a bigger deal. I disagree that GA isn't a big deal, having watched people try to GA good-looking articles and fail. I should have been clearer: this article was on the front page repeatedly, but not necessarily because it was a GA.

<comment><USER20> Ah, sorry, I misread your comment :)

(Agreed over GA, wasn't intended to belittle it!)

</comment></comment></comment></comment><comment><USER21> I'm amazed at the general support among comments here so far for the 'tertiary source' argument. Encyclopedias have always been written by experts -- usually one expert per article. Wikipedia itself has a template, 'This article is in need of input from an expert on the subject'.

But this isn't even right, because Wikipedia is a not an encyclopedia. It's like Johnson & Johnson saying Q-tips are for applying makeup or detailing cars and shouldn't be put in the ear. 99% of people who buy Q-tips put them in their ears. 99% of true claims on Wikipedia are contributed by experts and are either unreferenced, cite a source that doesn't really support them, a source at the other end of a broken link that nobody's read, or a source that doesn't meet the guidelines this historian was held to. Career editors spend more time checking _for_ citations than checking citations. And they spend more time checking for citations when they personally don't believe a claim. The policies are applied hypocritically, with the result that opinions of non- experts outweigh the opinions of experts. The only thing limiting the damage has been the relatively small number of career editors. With massive decline in casual participation in recent years, this balance is starting to shift. I just noticed recently that career editors have started to tag mathematics articles.

We should be honest that the encyclopedia contrivance is really just a way to avoid flame wars, and is an imperfect one, especially when editors 'merge with their cover story' and blindly enforce it. Wikipedia will be its best when it is recognized for what it is: a truth engine, a first source, and a very important public good.

Editing Wikipedia needs to be about more than writing long policy documents and bludgeoning contributors with them. It is an important form of scholarship. The project could benefit greatly by a reputation model more subtle than "barnstars", such as [1]. But a fancy reputation model alone isn't enough. The culture of Wikipedia is in trouble and needs to be revitalized.

[1] <http://www2007.org/papers/paper692.pdf>

<comment><USER22> > a truth engine

I don't know what that is, but I think if it ever existed it would be in the service of something foul and malign.

Humans have facts. Humans have evidence. Humans even, in mathematics alone, have proofs. Humans do not have truth. Woe betide anyone who thinks we do.

</comment></comment><comment><USER23> I have adopted the following policy about Wikipedia, and I think it reflects current state of affairs:

1\. It is a decent repository for bare facts that can be easily verified elsewhere, but assembled there in convenient form. E.g. if you need to know the population of Nepal, Wikipedia article about Nepal is a good way to go, even though multiple other sources are available.

2\. It is a decent source of links for more complex material - e.g., if you want to get a quick idea about what suprematism is, without knowing anything about it, and how to start researching the topic, you can use Wikipedia article, extract such keywords as "visual art", "Malevich", "russian avant- garde", etc. and take it from there if you're interested.

3\. It is a somewhat useful, but a dangerous source about any concepts that are in any way controversial - you should verify all claims and read all links, but you can use it as an assembly of links and keywords, without assigning too much importance to any narrative.

4\. It is absolutely useless for understanding any seriously controversial topic, as at best controversial articles would selectively present facts, reflecting biases of the writers, at worst - explicitly promote specific approach to the topic, which will be ruthlessly enforced by either the mob of opinionated editors or the wiki bureaucracy masterfully exploited by biased insiders.

To the defense of Wikipedia, some mainstream encyclopedic sources, especially ones published in non-free countries, suffer from even worse bias problems. I don't think there's a solution for this, except using one's own mind and take everything told to you with a grain of salt and check it when possible. Obviously, the topic described in the article falls into the third or fourth category, and so expecting Wikipedia to have anything but bare facts (like dates when it happened, names of the participants, etc.) right would be a bet, and not a safe one. In most cases it'd be whatever the random Wikipedia "guardian" or anonymous mob of agenda-bearers wants it to be. Sometimes the experts make the fuss that hits some popular media and particular article gets better, but most would give up and decide not to waste their time.

</comment><comment><USER24> Key sentence: "my citations to the primary documents were insufficient"

While I agree that the wikipedia gestapo are often overzealous with reverting good edits - it basically requires a case-by-case basis of deciding what 'facts' are, which is never easy. If his 'primary sources' are better than the secondary sources that say the opposite, then talk sense to the person who is doing the reversion, or raise it with someone higher - don't just continuously attempt edit-wars...

<comment><USER20> In fairness, he didn't attempt to edit war (only making the changes once) - <USER2> just gave up the discussion very quickly and didn't argue the point.

<comment><USER24> "So I removed the line.... Within minutes my changes were reversed. " "I tried to edit the page again. Within 10 seconds..." "Tempted to win simply through sheer tenacity, I edited the page again. My triumph was even more fleeting than before. "

<comment><USER20> He made three _different_ changes to different pieces of content. I see how he doesn't get that across well in the article, though.

</comment></comment></comment></comment><comment><USER25> This is exactly what Wikipedia should be doing. They cannot know what the truth is, they can only provide a summary of existing sources.

<comment><USER12> There's nobody I'd trust less than a Wikipedia editor to act as the arbiter of truth, but they could still do better. Wikipedía could adopt a policy of preferring primary sources over secondary, which would still keep out the "teach the controversy" cranks who are the obvious reason for the "undue weight" criterion without affecting well researched rebuttals of conventional folly. They consciously _choose_ to do the exact opposite, preferring popular opinion to actual verifiability, and IMO that's wrong.

<comment><USER26> Wikipedia has explicitly adopted the opposite policy, and they didn't do so arbitrarily.

In specific cases it might seem stupid, but I think in general it makes sense. It goes hand in hand with the "no original research" policy.

(Like everything in wikipedia that policy can be misapplied by small minded people, though.)

<comment><USER12> The "no original research" policy is fine when it prevents self-citation, but when it prevents citation of little-read but thoroughly credible third-party sources such as court transcripts that's a different matter.

<comment><USER4> No, it's really not. The proper venue for interpretation of little-read primary sources like court transcripts is a book or journal article, not an encyclopedia.

<comment><USER12> Nobody's talking about interpretation. I was referring to mere verification that the source exists and says what it's claimed to. That can _and should_ happen in an encyclopedia.

<comment><USER4> That's not what he did. He synthesized from the primary sources text that contradicted the majority of all published sources on the incident, including what was up until then the most authoritative source. That obviously should not be happening in an encyclopedia.

But let's be careful about wording. It obviously shouldn't happen _in an encyclopedia_. But it obviously _should be happening_. And it did. He went on to write an authoritative secondary source and the article is sure to reflect it.

</comment></comment></comment></comment></comment></comment></comment><comment><USER27> I can imagine this back in the day. "Though almost every scholar agrees that the earth (though flat) is the center of the universe, some people do persist in saying that the earth is not only in orbit around the sun, but is also round. Most of these minority claims rely on "mathematics" and other potentially incorrect "proofs" of their theorems."

I am reminded of the "paradigm shift" approach to the history of science, as flawed as it may be to some (look it up, sigh, on wikipedia). It implies that the dominant point of view is held as fact until a preponderance of evidence shifts the minority view from "flawed" to "edge cases" to "the new paradigm". Then it cycles again. What was the sworn truth with history behind it is now the "old paradigm" and disregarded.

For wikipedia, I've never felt there to be a requirement for "article completeness", just an eye to be "well rounded", and so it often feels that whatever the dominant paradigm is currently will be the primary driver of inclusion and presence in an article.

Wikipedia is in that interesting tension between sticking to it's original mission, which was pretty wonderful, and potentially becoming more, but at the risk of becoming useless. For all it's flaws, I still think the world is better with it than without it, and at some point, I suspect a way to let folks contribute more original research and have it coexist on wikipedia will evolve.

</comment><comment><USER28> Instead of fighting over the semantics of a single sentence why not instead elaborate on the evidence presented by the prosecution, then later discuss if the semantics of that summary sentence contradict the other information in the same article?

</comment><comment><USER29> One of the editors gave a form in which the newer research could be presented that was in compliance with their policy (the green sky blue sky example). Why didn't the author make an edit of his form? Something like: "Although most historians agree that little evidence was presented... newer research suggests..." It would get the new point across while keeping the prior, possibly fallacious, but accepted viewpoint visible.

</comment><comment><USER30> John Siracusa was complaining about the same thing recently. He also argues that it is possible to create a wiki where truth is more important than verifiability.

Hypercritical #53: Brad Pitt Gets to Contribute <http://5by5.tv/hypercritical/53>

</comment><comment><USER31> Looks like Wikipedia has been corrected as a result of this article. Well done to the author, and shame on those who try to distort the truth.

<comment><USER32> And well done to the Wikipedia editors, who didn't include the updated information in the article until it had gone through the academic publishing process and so been vetted by experts in the field.

</comment></comment><comment><USER33> "The truth is more important than the facts." --Frank Lloyd Wright. But unfortunately for Wikipedia <http://en.wikipedia.org/wiki/Wikipedia:Consensus> is more __important __than facts/truth.

</comment><comment><USER34> Academics vs. Wikipedia Grammaticians: <http://en.wikipedia.org/wiki/Talk:Fitts%27s_law#Grammar_edit>

</comment><comment><USER35> Ask HN: Is anyone working on this problem? any startups?

<comment><USER36> Citizendium was supposed to recruit experts to write articles, it's basically dead. [http://arstechnica.com/tech-policy/news/2011/10/five-year- ol...](http://arstechnica.com/tech-policy/news/2011/10/five-year-old- wikipedia-fork-is-dead-in-the-water.ars)

Google's Knol would have avoided a bunch of procedural mess, but it's been shuttered. [http://techcrunch.com/2008/07/23/googles-knol-the- monetizabl...](http://techcrunch.com/2008/07/23/googles-knol-the-monetizable- wikipedia/)

<comment><USER37> Thanks for mentioning that Knol has been shuttered. The TechCrunch link you kindly shared announces the launch of Knol, but I found the link

[http://techcrunch.com/2011/11/22/google-announces-plans- to-s...](http://techcrunch.com/2011/11/22/google-announces-plans-to-shutter- knol-friend-connect-and-more/)

that mentions Google abandoning Knol.

</comment></comment></comment><comment><USER38> Yes. Wikipedia is not for original research. Do the research, publish it, and _then_ update Wikipedia.

</comment><comment><USER39> Similar experiences here. In one case I even got corrected by a bot... I don't know if all the millions Wikipedia slurps up from their donations go to AI research, but I actually think the bot was wrong.

</comment><comment><USER40> Wikipedia will be destroyed when governments figure out that they can control what is and is not "authorized popular truth". Wikipedia doesn't stand up for truth, it only seeks to be based upon the data sources, even when we all know they are officially verified government propaganda.

That's why history books in middle school are completely screwed up with lies. You can't empirically test history. If wikipedia is to survive it will have to make a principled stand against official propaganda machines, official government sources and popular truth, myth and political agendas.

</comment><comment><USER41> There are a number of people who apparently monitor Wikipedia relentlessly, lest the truth appear. In general, they seem to be motivated by their devotion to the Big Lie, extremist political agendas, and general crankiness.</comment>


Does everyone agree AI is better than self discovery? - <AUTHOR> I get that computers can do things quickly, but this massive push into AI and pre-selected candidates seems somewhat misguided. Perhaps for high level areas, but not for something more meaningful or deep? Currently, I'm building this site https://nextcept.com/Feed/Network to help people find others to work with that they get along with. Ie. cofounders, early teams, new hires, etc. I continue to get suggestions that I need to offer suggested or recommended candidates. I suppose I see this to some degree, but am I alone in wanting to be able to wander through candidates, learning about them individually, until I find someone interesting. Obviously we're trying to make this wandering process more efficient, but it seems like something unique or something that stands out would be difficult to capture in an algorithm. Is this a misguided belief? Does everyone want (believe it's possible) the ease of Tinder but the depth of a real connection - magically? <comment><USER2> Lecturer and teacher Scott McCloud once said this to the effect of hiring practices, how there are three anchors from which an employer of any variety must seek out among potential employees.

To turn in work of professional and skilled caliber, to do so always ahead of deadlines, and to be easy to deal with generally.

A person only offering one is not providing enough to make their employ worthwhile or long-lasting, while the chances of someone realistically offering all three are extremely rare. So, the idea is to look for somebody what can comfortably guarantee any two of the three anchors. For example, a person may only submit average-quality work, but if they are reliable for at least that much and are easy to work with, then they are employable. Or, a person might be notorious for blowing schedules, but if they are always friendly about it, and their end product is always outstanding even though late, then they themselves are worthwhile.

But no psych test in the world can guarantee with 100% accuracy exactly how people might work together. Too many variables and too many subjective variables.

</comment><comment><USER3> Not magically.

I used to put down the leaders of big businesses for the various screw-ups you read in the news, such as the 2008 financial crisis, Carly Fioria destroying Bell Labs and nearly destroying HP, the recent meltdown at GE, the 737 MAX scandal, etc.

Over time I realized that incredible screw-ups happen all the time at small businesses (say a small-town general store) or medium businesses (say a venture-funded startup) If the people who ran big companies screwed up as often as the people who run big companies, we wouldn't have any big companies!

You might not need a 10x salesman to be a 10x developer, but the failure of any part of the value chain can multiply the value of your work by zero!

There probably is some way to measure the pathology that I mention, but it's not going to be superficial or "magic".

</comment><comment><USER4> Most people in dating have deal breakers. I feel like there should be some way to filter out deal breaker issues.

<comment><AUTHOR> This is a good idea. I've been trying to build in methods for determining if you'll get along with a person, but the idea that you might be able to filter based on deal breakers is interesting. Or to filter based on what's not needed. I think there's this motivation for companies no a days to aim for their perfect candidates who know 40 languages and I never really know why. Is that really their goal? Do they just want someone to say they know all of those things? Why not just focus on what's needed and what's needed a little down the road. It seems like if a person could help with that, they'd be helpful in the future.</comment></comment>


The total weight of all Bitcoins today: 3 kg - <AUTHOR> The amount of energy required to create a parallel (fake) chains is so huge that it makes more sense to express it in kilograms.
Some back-of-the-envelope calculations based on total sustained mining power consumption in 2017, extrapolating back, using the good old E=mc^2, yields the average weight of a bitcoin of about 0.2mg.
This makes Bitcoin the most expensive substance today. <comment><USER2> That is not the only flow of or reservoir of energy and/or mass associated with bitcoins.

Consider, carbon added to the atmosphere to make that energy, kg of fission products to do the same, mass of all the servers running Bitcoin software, mass of party favors left over after Bitcoin conference, etc. Any of those is much greater than 3kg.

</comment><comment><USER3> Most expensive compared to what?</comment>


Show HN: Simple PC System Builder - <AUTHOR> https://pchound.com/ <comment><USER2> I tried it for a bit and liked it (in fact it's better than the sites where I shop), but what's the use case ? Is it a demo of your skills or you plan to sell it (or maybe just get money from Amazon referrals) ?

<comment><AUTHOR> The main benefits are that it 1) allows you to price compare and 2) it checks compatibility to you don't make mistakes. Hound-O-Matic is a completely automatic and requires simply a budget / vague filters.</comment></comment>


Sudden Progress on Prime Number Problem Has Mathematicians Buzzing - <AUTHOR> http://www.wired.com/wiredscience/2013/11/prime/all/ <comment><USER2> When I ordered a set of three foot-long chicken parmesan sandwiches from Subway a few weeks ago, the guy behind the counter said, "Because prime numbers are fundamentally connected with multiplication, understanding their additive properties can be tricky."

I was confused at the time, but it makes sense now.

</comment><comment><USER3> Two points:

\- In math, an innovative "attack" (such as a technique to approach a problem) can result in years of subsequent research that progresses a field. Zhang deserves a lot of credit for his accomplishment!

\- He shouldn't have had to work at subway. If only our society held intelligent people in the same regard as athletes. What we have right now (hoops to get tenure, publish or perish culture, etc.) is a joke. I review papers for some notable conferences in my subfield in CS. This week I read about a dozen papers. The ones that pained me the most were written by very smart people solving made up and artificial problems. But hey ... you need to publish this crap to graduate/get tenure/get next grant/whatever. How about a basic income for everybody with a PhD?

<comment><USER4> "How about a basic income for everybody with a PhD?" How about a basic income for everybody?

I am always amazed, how unsuccessful PhDs in life are. Myself included.

<comment><USER5> Why? Existential crisis?

<comment><USER6> A doctorate in most fields is proof of a degree of general smartness and an ability to work rigorously in the field. It doesn't necessarily have anything to do with good judgement, luck, diplomacy, social skills, practical skills, or any of the thousand other things that contribute to success in life.

<comment><USER7> To do a PhD you have to be smart enough to be _able to_ do one, and dumb enough to _actually_ do one.

<comment><USER8> In my opinion rather smart and _despaired_ enough to actually do one.

</comment></comment></comment></comment></comment></comment><comment><USER9> > There are a lot of chances in your career, but the important thing is to > keep thinking

I hope this quote gets picked up and cited throughout future history

<comment><USER10> What is it about this quote that makes you feel it should be cited throughout future history? Just curious.

<comment><USER11> It seems some people think being reminded to think is profound.

</comment></comment></comment><comment><USER12> Previous discussion here: [https://news.ycombinator.com/item?id=6766097](https://news.ycombinator.com/item?id=6766097)

<comment><USER13>
        Previous discussion here

272 points, 93 comments, 3 days ago.

</comment></comment><comment><USER14> I'm confused by the "Admissible Combs" sidebar. Can someone help me understand?

"Roughly speaking, a comb is admissible if there is no obvious reason why its teeth couldn't point entirely to primes infinitely often as you move it along the number line"

Then: "A much more audacious conjecture called the prime k-tuple conjecture ... posits that any admissible comb will point entirely to primes infinitely often."

Isn't this just saying the prime-tuple conjecture states that admissible combs are admissible?

<comment><USER15> Admissibility doesn't say that a comb's teeth _will_ point entirely to primes infinitely often, it merely says (as you quoted) that there's no _obvious reason_ its teeth _won 't_ point entirely to primes infinitely often.

I suspect that "obvious reason" is being used as shorthand for some technical definition the article doesn't try to state. Any mathematician here that knows more?

<comment><USER16> Sure. {n, n + 2, n + 4} is a 3-tuple that is _not_ admissible: One of n, n + 2, and n + 4 will always be divisible by three, so the tuple has no chance to ever represent three prime numbers for one value of n. (Except for n = 3.)

Conversely, {n, n + 2, n + 6} is an admissible 3-tuple. There's no fixed integer that will always divide at least one of n, n + 2, and n + 6, so we believe that there are infinitely many n for which n, n + 2, and n + 6 are all prime.

<comment><USER15> And so the claim is that there is no less obvious reason that a comb might not be all primes only finitely often. That _is_ an audacious claim :-).

</comment></comment></comment></comment><comment><USER17> Not being able to understand the intricacies of this proof, I can take away but one message. Genius can come from anywhere, even from an academic who was only able to find a job working at a Subway diner. So be open to good ideas - they can come from anybody, anywhere.

<comment><USER17> And to top it all off, this Mathematician was in his late fifties when he published his breakthrough proof!

<comment><USER18> It's not the age, it's the marital status that affects the productivity the most.

<comment><USER19> I find myself downright inspired as a family man.

<comment><USER20> You should feel depressed instead. In men, creativity is destroyed by marriage [http://www.abc.net.au/science/articles/2003/07/11/900147.htm](http://www.abc.net.au/science/articles/2003/07/11/900147.htm)

<comment><USER19> I'm very appreciative of the the statistical concept of outliers.

As Hume would point out, is is not ought.

</comment></comment></comment></comment></comment></comment><comment><USER21> Does this mean as much as I think it does? Aren't most of our current cryptography schemes based on prime numbers taking time to calculate?

<comment><USER22> No.

Finding random primes is easy, especially if you don't mind using methods which allow an extremely tiny probability of error [1] -- this is standard practice in cryptography.

Finding random big primes p and q is easy. Multiplying them together into a product r = pq is easy. RSA cryptosystem picks p and q when generating the key, multiplies them, then throws away original p and q values. Only r is stored in the key.

Cracking the RSA algorithm itself [2] is basically equivalent to turning r back into p and q.

RSA is based on the hardness of factoring an integer into a product of primes. I don't think this conjecture will lead to practical improvements in cryptography / cryptanalysis, at least not with respect to cryptosystems that are currently widely used.

[1] [http://en.wikipedia.org/wiki/Primality_testing#Probabilistic...](http://en.wikipedia.org/wiki/Primality_testing#Probabilistic_tests)

[2] Of course, there are many more attack vectors on specific _implementations_ of the RSA algorithm, like trying to gain information on the secret key by measuring time taken to encrypt a message, measuring heat/power consumption/electronic noise, taking advantage of implementations that use a poor source of randomness, hacking into the system where the private key is stored, or bribing/threatening a human with legitimate access to the private key (as covered in [http://xkcd.com/538/](http://xkcd.com/538/)).

<comment><USER23> _" Finding random big primes p and q is easy"_

For those wondering why then, it is news when a new largest prime is found: there are gradations of 'big'. The big primes used in cryptography have fewer than 1000 bits, or about 300 digits. That is not what one (nowadays) calls 'large' in the field of finding the largest prime. There, one laughs at numbers of a million digits (the largest known prime has 17,425,170 digits)

<comment><USER22> Also, for a practical engineering problem, like writing an RSA implementation which will be used in an SSL implementation which will encrypt credit card numbers on an e-commerce website, it is okay to use probabilistic tests which have a tiny chance of a false positive (the test claims a number is prime when it is actually composite).

You can generally repeat a probabilistic test with different parameters to make the probability of a "false positive" prime number very tiny -- like .000 000 000 001 -- while still staying within the computational budget manageable on an ordinary computer (obviously, a practical Internet security scheme should be able to complete its computations in a second or two on a typical desktop, laptop, server, and smartphone).

So probabilistic tests are good enough for practical purposes, but you need a non-probabilistic test to get the false positive probability all the way down to zero. And you need to use a method that has zero percent false positive chance to claim a world record. The EFF-administered monetary prize for a record-breaking prime number, for example, requires "the primality proof must be a deterministic proof..." [1] So you can't use probabilistic methods.

[1] [https://www.eff.org/awards/coop/rules](https://www.eff.org/awards/coop/rules)

<comment><USER24> I know (or think) that most record primes these days are Mersenne primes due to the relative ease of testing their primality. What I wonder is if probablistic tests could be used to find candidates for very large non- Mersenne primes before testing them using AKS.

Or is o̅(log⁷·⁵(n)) just infeasible for those sizes of numbers?

</comment></comment></comment></comment></comment><comment><USER25> Since counting numbers are so regular I've always wondered why finding primes is so hard. Then again I have no hair so using combs is a mystery.

</comment><comment><USER26> Related questions, what are the open problems with prime numbers? Not that I'd ever solve them, but I was having fun using machine learning algorithms try to predict the next prime number in a sequence and it was kind of interesting.

<comment><USER8> \- Goldbach's conjecture ([http://en.wikipedia.org/wiki/Goldbach%27s_conjecture](http://en.wikipedia.org/wiki/Goldbach%27s_conjecture))

\- Goldbach's weak conjecture ([http://en.wikipedia.org/wiki/Goldbach%27s_weak_conjecture](http://en.wikipedia.org/wiki/Goldbach%27s_weak_conjecture)) - Harald Helfgott claims that he proved it

\- Is factoring in P? (it is known that prime testing is in P; thus the factoring is in NP ∪ coNP) - if it were true, RSA would be broken immediately (and some expert that I talked to told me, he believes that such a factoring algorithm could probably be extended to break ECC, too)

\- Riemann hypothesis ([http://en.wikipedia.org/wiki/Riemann_hypothesis](http://en.wikipedia.org/wiki/Riemann_hypothesis))

\- Do for each even number n exist two prime numbers p > q such that n = p-q?

</comment></comment><comment><USER27> What I find surprising is that there's an online tool for math collaboration (github for maths?), and that it turns out to be rather useful.

</comment><comment><USER5> Are they still at 600?

<comment><USER28> This abstract suggests that the bound may be lower:

[http://jointmathematicsmeetings.org/amsmtgs/2160_abstracts/1...](http://jointmathematicsmeetings.org/amsmtgs/2160_abstracts/1096-11-441.pdf)

From [http://jointmathematicsmeetings.org/meetings/national/jmm201...](http://jointmathematicsmeetings.org/meetings/national/jmm2014/2160_program_ss23.html)

<comment><USER20> No. That abstract says that the bound it 12 if the Elliot-Halberstam conjecture holds. Under that assumption, the bound has been 16 since 2000. The trick that brings the number down from 16 to 12 under that assumption is the same that brings the proven number down to 600. This is actually described in the linked wired article.

<comment><USER5> Ah. Thanks for the clarification.

</comment></comment></comment></comment><comment><USER29> Current list of attempts:

[http://michaelnielsen.org/polymath1/index.php?title=Bounded_...](http://michaelnielsen.org/polymath1/index.php?title=Bounded_gaps_between_primes)

</comment><comment><USER30> Could someone explain this in layman's terms? What does it mean to have infinitely many pairs of primes separated by 600?

<comment><USER31> If the original claim is true, it means that the maximum numerical separation between primes is 600, meaning primes may sometimes be separated by a smaller gap, but no two primes will be separated by a larger gap, a numerical distance greater than 600. What this means is, if there are no gaps between primes _a_ and _b_ greater than 600 (i.e. |a-b| > 600), if all prime pairs have a smaller gap, then given the size of the set under consideration, it follows that there are an infinite number of pairings {a,b} in which their separation is 600 or less (|a-b| <= 600).

Also, in mathematics, finding an example of a property isn't very difficult. The difficulty lies in proving a theorem that makes a universal statement about that property -- that's the real challenge.

If that answer wasn't clear, don't hesitate to ask a clearer question.

<comment><USER32> I don't think this is right.

There are certainly prime gaps that exceed 600. In fact, the higher you up (in the number line), the higher these prime gaps tend to get.

[http://en.wikipedia.org/wiki/Prime_gap](http://en.wikipedia.org/wiki/Prime_gap)

What's being said here is that despite of that, there will always be prime gaps smaller than 600. No matter how high you go, you can always find a pair of primes that are separated by less than 600. In other words, pick the biggest N you can ever dream of, and there will exist primes p1 and p2 such that they are both bigger than N and their difference is smaller than 600.

<comment><USER31> Yes, you're right, and it's too late for me to either delete or edit my original post. :(

In light of that, I think the discussion and work revolves around discovering the smallest gap as the numbers themselves become larger and tend toward infinity. Obviously the very smallest prime gap is that between 2 and 3, i.e. 1, and there are a great number of primes separated by 2, and the Twin Prime Conjecture asserts that there will always be occasional pairs of primes separated by 2 no matter how large the numbers themselves become. The present work is in part meant to put that conjecture on a more analytical footing.

I would love to delete my original post.</comment></comment></comment></comment>


Archive that can be reconstructed with total loss of file system structure - <AUTHOR> https://github.com/MarcoPon/SeqBox <comment><USER3> This is a cool idea. Please don't take the below as gratuitous negativity, just a reminder that these are hard problems for which there are no general solutions.

The README says it was tested on ZFS, but I doubt its utility in real-world deployments. I don't know of anyone who has significant data in a ZFS pool that isn't one or more of: raidz, compressed, encrypted, or embedded_data.

raidz implies that logical blocks aren't allocated as single physical blocks, but instead striped across multiple drives. Finding the SBX magic isn't enough to get you the rest of the block, but the checksum might (but, given that's it's CRC16, probably won't) let you try appending blocks from other disks to find the remainder of the block.

Transparent compression prevents you from identifying the magic header on each block, unless you decompress every disk sector that could have data (which is certainly feasible, but complicates recovery if you don't know which compression was in use, and zfs supports at least 3 kinds, and pools will generally have at least 1 in use whether compression is on or not).

Encryption (present in Oracle ZFS) means there's no plaintext data to recover.

embedded_data is a feature flag (and on by default in supporting versions of zfs) that packs blocks into block pointer structs when the amount of data is small. I can easily imagine the final block of an SBX, which may be mostly padding, getting compressed into one of those block pointers, which itself may be embedded in a larger structure which is part of an array that's compressed by default. That array is also probably long enough the compressed stream takes multiple blocks, and you may have lost some of the early ones, making the rest of it unrecoverable.

</comment><comment><USER4> Alba ( [https://github.com/openvstorage/alba](https://github.com/openvstorage/alba) ) implements the same idea, but for a distributed object store: The objects (files) are split into chunks and erasure coded into fragments, which are stored on storage devices (disks). The structure of the object and the metadata is stored in a distributed key value store. _BUT_ The metadata is also attached to the fragments so that if the distributed key value store is lost, everything can be restored from the storage devices alone. Obviously, this is a very heavy operation and is the very last line of defense against data loss, only needed in case of a severe calamity.

</comment><comment><USER5> Sounds like it would have been useful in 1998, when filesystems and drives were less reliable and encryption was rare.

</comment><comment><USER6> The author Mark0 writes: "each SBX file can contain only 1 file and there are no error correcting informations (at least at the moment) ... But it's possible to create an SBX file out of a RAR archive with recovery records, for example."

IMHO that would be the win-win combination for data recovery. How common is the failure scenario? Common enough that there are people who make a living piecing lost files back together. See [http://forensicswiki.org/wiki/File_Carving](http://forensicswiki.org/wiki/File_Carving)

More discussion at [https://www.reddit.com/r/datarecovery/duplicates/66hgnt/i_ma...](https://www.reddit.com/r/datarecovery/duplicates/66hgnt/i_made_a_thing_that_may_be_of_some_interest/)

</comment><comment><USER7> This looks great! So I will ask the obvious question - how common is the failure scenario this protects against compared to others?

<comment><USER8> I would say rather common.

The whole issue is that file carving (once filesystem structures are destroyed) works fine with contiguous data but it doesn't work (or it works only very partially, and depending on a number of factors) with any fragmented data.

But I will give you a common enough example, that I have seen happen many times.

The user wants to format a USB stick, but by mistake he/she selects a data volume instead.

Two possibilities (under Windows later than XP):

1) user chose NOT the "/q" (cli) or "quick" (GUI) format, all data is lost forever as starting from Vista if a "full" format is cosen the whole volume will be overwritten with 00's

2) user chose to "quick" format, only the filesystem structures are recreated (blank) and - given that the volume was originally formatted on the same OS - they will be exactly where previous filesystem structure were, thus cleanly replacing them.

In this latter situation all files are still there, what is lost is where they are, the address info for a contiguous file is two pieces of data, where it begins and how big in size it is, there are a number of programs that can "recognize" a file (or its beginning) by its "signature" (usually a header, but sometimes a combination of header and footer), among them the excellent TriD tool by the same Author Marco Pontello, and a large number of file formats do include some info on the filesize, and there are slightly more sophisticated programs that can usually recognize if data belongs to a given filetype.

The address info of a fragmented data is as many starting points and as many extensions as the fragments, and since a fragment - bar the first one - <USER2> no headers it is extremely difficult to find all the fragments of a file (and knowing to which file a fragment belongs) and re-build the file by re- assembling the fragments in the right order, often impossible.

In a nutshell, if the volume was only made of contiguous files, they can be recovered 100% or very near 100%, only losing their filenames and their path in the "previous" filesystem structure.

BUT any file that was fragmented will either be lost completely or will need (in some cases only this is possible) manual reconstruction, something that may take days or weeks of work and very often with only very scarce or partial success.

The idea of a "self-referencing" archive with sector-level granularity is simply great, you won't ever _need_ it, but if you do, it could be a lifesaver.

<comment><USER9> When I was younger I worked a while in file carving problems and algorithms, and while your take on it is accurate, it's not complete. There are algorithms that can do what you call "manual reconstruction" in a more or less automated way. Of course, as with everything that is automated, there are edge cases where it doesn't work correctly, but it'll save you a lot of time.

What has been discussed here and in the OC, is mostly header-footer carving, but file-structure-based carving has been around for a long time already (I think Foremost included it in 2005/2006, and PhotoRec supports it for _some_ formats). Using the file command (*NIX) or TRiD to find the headers is a bit of a hack, and useful only if you want to sit a long time with dd (or an equivalent tool) and direct yourself the carving process.

As for the fragmentation issue, there used to be around a great program called "Adroit Photo Forensic" which implemented the amazing SmartCarving(TM) approach (academically known as graph-theoretic-carving) in which the disk is scanned, pools of segments by file format are populated, and then a graph is constructed and analyzed with a Dijkstra's shortest-path variant which works on multiple paths from multiple starts-to-ends. Very interesting, though a bit computationally expensive. Plus you need an extremely precise similarity metric between the segments, which was actually the weak-spot for this. However, it seems as if the Adroit product has died (I can only find mirrors now which host old versions of it), and as it was a try-and-buy program I don't think you'd be able to use it now.

Thing is, there are easier ways to handle fragmentation. For example, PhotoRec itself lets you pass an agressive validation step, to discard most of the "probably wrong" recovered files, and then dump the remaining to an alternative disk image, on which you can try carving again. Of course, this iterative process takes time, but it can work, and of course it can be automated (and thus, saving you from manual intervention).

While my work has taken me away from it, I never quite understood why the digital forensics community "forgot" about file carving, or disregarded it as an important problem -- it seems as if there are still the same issues around as when I worked on it, while having less tools available.

As for the SeqBox format, more than an alternative to this tools, I find it as an interesting complement to them.

<comment><USER8> Sure, I tested a couple of times Adroit, anyway it is (was) only about some specific file formats (photos, aka jpeg's), and even the Authors' "pitch" was about (only) 20% more photos recovered, I remember not being that much impressed by the results of the actual tests (but maybe the devices on which I tested it at the time also suffered from other forms of corruption): [https://web-beta.archive.org/web/20120313073659/http://digit...](https://web- beta.archive.org/web/20120313073659/http://digital- assembly.com/products/adroit-photo-forensics/)

[https://web-beta.archive.org/web/20120806031446/http://photo...](https://web- beta.archive.org/web/20120806031446/http://photo-recovery.info:80/)

Some info about Smart Carving (for those interested):

[http://www.forensicswiki.org/wiki/File_Carving:SmartCarving](http://www.forensicswiki.org/wiki/File_Carving:SmartCarving)

and GuidedCarving:

[http://www.forensicswiki.org/wiki/File_Carving:GuidedCarving](http://www.forensicswiki.org/wiki/File_Carving:GuidedCarving)

I am pretty sure that a similar tool (specific for photos/jpeg's) would be very useful, but extending the same principles to different file formats is - as I see it - extremely hard and in a large number of cases simply impossible (due to the actual structure of the file format itself).

<comment><USER9> Depends on the format, for example PNG has checksums per segment which make it extremely easy to find if the segment has been correctly rebuilt. Same goes for ZIP and RAR, and JPEGs can be matched against the Huffman tables for invalid byte sequences.

Also for JPEG there was a (sort of experimental) carver that validated the image against the thumbnail, and then decided if it was correctly reconstructed or not (and maybe it also helped to choose the correct block when there was an error). Still, most of this tools never left the alpha stage, and ended as curiositys presented in a conference and then left to rot.

<comment><USER8> Yes :), it is queer how some programs/tools that _should_ exist and of which we do have the basic algorithms were never properly written/developed while we have tens or hundreds of tools similar among them missing these functionalities. Another kind of tool that was never properly developed is interactive jpeg repair, besides the good jpegsnoop: [http://www.impulseadventure.com/photo/jpeg- snoop.html](http://www.impulseadventure.com/photo/jpeg-snoop.html) (which has only some of these functionalities) there are a handful of tools that are of little or "very narrow" use, but nothing much effective at rebuilding a damaged jpeg.

<comment><USER9> I've seen this in the steganography/steganalysis "community": almost every time a script or program is written, its purpose is to rapidly fix the needs by some highly specialized expert who deems that development too simple (that is, to himself) to further develop into a full-fledged tool.

</comment></comment></comment></comment></comment></comment></comment><comment><USER10> This brought parchive/par2 to mind; as I recall, given an index file, which you could keep separate, you could do a rolling scan for the recovery blocks and file blocks on the disk, even without the file system structure. Unfortunately, it sorta looks like that software hasn't been worked on in a while.</comment>


Carousals in Emails - <AUTHOR> http://freshinbox.com/resources/tools/carousel/ <comment><AUTHOR> Except gmail works everywhere</comment>


Welcome to New York City, 1609 - <AUTHOR> https://welikia.org/explore/mannahatta-map/

<comment><USER2> As it happens often, the title says New York City but it is only for Manhattan. It would also be nice if there were maps in-between 1609 and today to see which areas were built at different times.

</comment><comment><USER3> Hey, my neighborhood was in the East River!

Unfortunately, I think that has implications for how flood-prone the neighborhood is too.</comment>


Computing with traps - <AUTHOR> https://www.github.com/jbangert/trapcc

<comment><USER2> Author here. The point of this work is not only the specific result (lots of VM edge cases, very hard to reverse engineer source of computation), but to promote this general class of 'problem' \-- things that are typically not thought to be so complicated actually containing a Turing-complete executionenvironment. Other examples include ELF and DWARF binary files, PDF, etc. etc.

Once you need to evaluate a Turing machine to see what a file (or in my case, a set of page tables) actually means, you loose a lot of tractability.

</comment><comment><USER3> Sounds like a good test case generator for the trap handling in virtual machines.

</comment><comment><USER4> One important thing to note about this is that it requires writing to the page/descriptor tables, so it must be done from ring 0. It makes a great "stress test" for emulators though.

</comment><comment><USER5> > One practical use of this technique is for code obfuscation - many (kernel) > debuggers will break due to the frequent context switches (esp. cooperative > debuggers like KGDB) and analyzing the binary is going to be extraordinaly > confusing, especially if normal X86 instructions and trap instructions are > interleaved to do weird control transfer. Furthermore, out of the many > virtual machines only Bochs runs such trap based programs correctly (and > there are other tricks to distinguish bochs from a real box).

In other words... security through obscurity.

<comment><USER6> All security is through solutions being obscure. I don't understand this criticism. Encryption just puts mathematical bounds on the obscurity, for instance, and a lock only works through the obscurity of having to find a crowbar.

Security is measured through degrees and layers. No secure system is provably secure to all attacks. Something like the above would definitely add a lot to the cost of attempting to understand the data flow, and that shouldn't be discounted. If I were building a root kit/drm, this would be a pretty decent way for me to hide data and computation long enough for me to adapt, away from the tools and patterns people understand.

Security through many layers of obscurity is how our internet doesn't fall apart. Just think about the massive amounts of plaintext email you can sniff between servers.

<comment><USER5> > All security is through solutions being obscure. I don't understand this > criticism. Encryption just puts mathematical bounds on the obscurity

There is a difference. Once somebody writes a tool to unravel the obscurity, it is simple and fast for everybody to break the security.

Not so with encryption (if used properly, with changing keys, one-time passwords, etc.)

<comment><USER6> > Once somebody writes a tool to unravel the obscurity, it is simple and fast > for everybody to break the security.

Yes, it has a lower bound. But that tool has a high obscurity level itself. So the lower bound on breaking the security is finding someone who can write that tool.

Not great, but decent to buy time, as I said before :)</comment></comment></comment></comment>


At Multiverse Impasse, a New Theory of Scale - <AUTHOR> http://www.simonsfoundation.org/quanta/20140818-at-multiverse-impasse-a-new-theory-of-scale/ <comment><USER2> I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.

<comment><USER3> I do not think that it is possible.

Any physical system that can be described by a set of mathematical laws is bound to have some axioms that simply cannot be proven within its context. Godel's incompleteness theorems prove that.

Hence, we will never get to the bottom of the reality of our universe.

<comment><USER4> Your statement that we will never get to the bottom may be true, but the reasoning is flawed.

Gödel's incompleteness theorems are about mathematical theories, not about physical theories. It may well be that for physical understanding a very limited arithmetic is sufficient. Also, there may be statements that are unprovable, but these might turn out to be irrelevant to sufficiently understanding the universe.

Also, an axiom, by definition, can not be proven. The things that are proven are theorems, statements, etc. An axiom is an assumption.

Eventually, it all depends on what level of understanding you want. But Gödel's theorems have little to do with that.

<comment><USER5> Do you not have to start off with a set of axioms though? Assumptions that will never be proven?

<comment><USER6> From the mathematical point of view, physics is about finding smallest set of axioms from which you can mathematically derive complete theory of universe's behavior. Validity of such axioms is in turn validated by experiments (by testing whether results match theory derived from given axioms)

<comment><USER7> It _is_ true that they will never be "proven", but that doesn't mean we can't build a tremendous confidence in them through experimentation. (Which is to say "I agree", but I wanted to put a slightly different spin on it.)

</comment></comment></comment></comment></comment></comment><comment><USER8> There's a very subtle undertone of negativity in this article about physics. Before I get into, William Bardeen is not in the same league as 'Surfer Dude and his E8 Theory of Everything' which throws basic facts about representation theory out the window, coming up with 'todalay boogus' arguments which amazes auntie, mommie and magazine editors but a real physicist would instantly dismiss.

Bardeen is the real deal. His papers are very interesting and feel a bit like reading Sidney Coleman's papers. If you're interested...

[http://arxiv.org/find/hep- th/1/au:+Bardeen_W/0/1/0/all/0/1](http://arxiv.org/find/hep- th/1/au:+Bardeen_W/0/1/0/all/0/1)

Is nature scale invariant? So far the answer is absolutely NO but I strongly advise to wait and see. There are many topics that point to some breakdown in scale or reorganizing what we think of space and distance (dualities in string theory, conformal field theory).

OK, now the important thing I want everyone here to realize. You are living through a GOLDEN AGE of physics. You wouldn't think that based on what all the popular magazines tell you. Here's why...

1\. Higgs particle - discovered!

2\. Inflation - discovered! Denying this one is like denying the Big Bang itself. The evidence is overwhelming and in fact I would list this as the single greatest scientific discovery of all time. The concurrent discovery of gravity waves, quantum gravity and a real life example of a Hawking process only sweetens the deal.

3\. Supersymmetry has basically already been discovered IMHO. They aren't announcing anything at CERN and won't until they have so many sigmas under their belt but trust me, it's coming and truth be told, it isn't really so surprising. SUSY physics has always been rock solid from the beginning. The situation is very similar to that before offical Higgs announcement and before someone went knocking on Andre Linde's front door. Many were extremely confident in the Higgs particle a least a year before the official announcement. The BICEP 2 results were even more glaringly apparent than the Higgs results. Many people were walking around the Earth with 'secret knowledge' that inflation theory was correct even 2 to 3 years before the official announcement.

So you are living through EXTREMELY interesting times but you wouldn't know it with all the big science bashing being thrown around.

<comment><USER9> So, erm, what does that buy us?

I'm just an engineer, so I'm not sure I see the utility in any of that--sorry to sound closed-minded, but am genuinely curious.

<comment><USER10> Basic research is the foundation of all engineering. You can't design things without understanding how the universe works. If you need examples, look no further than to particle physics, which has had a huge influence on medical imagery since at least the fluoroscope.

<comment><USER11> All things hitherto designed have been designed without a complete and truthful understanding of the universe. If we go back in history, we find examples of useful inventions that were produced amid a rather poor understanding. Levers and inclined planes were produced without knowing anything about basic arithmetic, let alone physics.

</comment></comment></comment></comment><comment><USER12> >With their field stuck at a nasty impasse

of course. Natural thing when a field is dominated by orthodoxy that closes their eyes to everything that they don't want to see. Like yesterday "entangled photon imaging" where what really happens is that a beam modulated by an image heats/excites crystal (with that heating/excitement thus obviously modulated by the image) which generates another beam (thus that another beam is obviously also modulated by the image) which hits CCD - no miracle of entanglement here, yet Nature published it as such : [https://news.ycombinator.com/item?id=8234221](https://news.ycombinator.com/item?id=8234221)

as "entanglement" and "mutiverse" are very much in fashion this season and get you published.

With Higgs as a "mass" boson it was also non-starter because the theory of it failed to address gravitational and inertial mass equivalence. I mean i don't doubt that CERN found new particle of course, yet nowhere it was shown that it is the boson "generating mass". The article seems to suggest that finally the mainstream physics starts to seriously ponder whether the mass is a result of dynamic interaction - that has been obvious for decades to the "fringe" physicists, who couldn't just dismiss the above mentioned gravitational and inertial mass connection, a pretty fundamental fact that has to be at the center of anything called physics :)

<comment><USER13> I wouldn't say that the "field is dominated by orthodoxy that closes their eyes to everything that they don't want to see".

I'll admit most physicists I've met are suspicious of wild-eyed theory. But I wouldn't say they're overly orthodox. I think it's more a healthy skepticism of anything which involves humans projecting science-ficiton wish-fulfilment into science.

I'd go further and say that "entanglement" and "multiverse" are not at all en vogue. I think most seasoned physicists realize that these were trendy fields some years ago (for solipsistic reasons - ie, make us feel special).

So I think the return to a fundamental assessment of phenomena is pretty natural thing. Calling out assumptions like scale. What's more, I think the more discerning will also be suspicious of the "post-multiverse" dialectic. It's just the process really.

<comment><USER12> >I'll admit most physicists I've met are suspicious of wild-eyed theory.

...

>So I think the return to a fundamental assessment of phenomena is pretty natural thing. Calling out assumptions like scale.

i see big difference between "Calling out assumptions like scale" as a "return to a fundamental assessment of phenomena" and "Calling out assumptions like scale" in order to fit it into a wild-eyed theory like superstrings (basically to salvage the theory).

</comment></comment></comment><comment><USER14> I don't see why this kills the multi verse theory. Which is a basic conclusion of a 10 dimensional space-time environment that doesn't include mass anyway.

<comment><USER15> It "kills it" because it's only really appealing if the universe we're in appears extremely unlikely, like it's the "just right" goldilocks balance of cosmic variables that we can't explain, that happened to be the stable ones that resulted in life evolving eventually.

If the universe is actually very likely to occur in the state that it's in, then we don't need to use this "vast multiverse where our universe was the one that produced an observer" explanation. It could be a single universe in all of existence, where everything makes sense mathematically and no further posturing is required in that silly unscientific field of cosmic philosophy.

Or if it fails, and it remains that our universe is unexpectedly perfect, then we are forced to resort to statistical explanations within an impossible-to- observe external multiverse. Scientists don't very much like conclusions built on not being able to observe things.

Though to me, the multiverse theory has a sort of fractal appeal to it. It is surely applicable to our planet, after all. Why not our entire universe?

<comment><USER16> Naive question (I know nothing about this stuff):

If mathematical logic is a property of our universe, then aren't we again entering the realm of circular logic? i.e: "Given the logical frameworks that are correct in our universe, our universe is very likely."

Unless math is something that somehow exists independently of our physical universe... but then "where" does it come from?

<comment><USER15> I have no idea, really.

My hunch is that mathematics is more than universal; truths hold regardless of which medium of calculation is used to conclude them.

In any case, our conclusions about our own universe at least hold within our own universe, and are therefore still very useful for our own understanding thereof.

</comment></comment></comment></comment><comment><USER17> For a heroic attempt to explain this article to laypeople, check out physicsmatt's comments over at Metafilter:

"First, for maximum sense-making, read my previous comments here, here, here, and here. I realize that's a lot, sorry. The Universe is complicated. Then, for what follows, recall that to a particle physicist such as myself, there is no difference between lengths and energies (or indeed, any other dimensional quantity). Length is inverse energy: very energetic phenomenon probe very small lengths ...."

[https://www.metafilter.com/142211/Multiverse-No-More-a- New-T...](https://www.metafilter.com/142211/Multiverse-No-More-a-New-Theory- of-Scale#5703172)

<comment><USER18> Or don't - it's incredibly badly written, in the sense that it often descends into grammatical gibberish, even without worrying about the physics the gibberish is trying to describe.

<comment><USER15> There's really not that much to understand, and the details aren't that important unless you're living them.

The question boils down to this: are we one of an infinite number of universes that popped into existence that just happened to have the right variables to be stable and result in life? (The anthropic principle, a statistical conclusion, and a philosophical mind-bender...)

Or are we in a single universe whose properties are mathematically aligned in such a way as to be very unlikely to result from chance, even if repeated an infinite number of times? The details of this are interesting, but extremely numerous and complex: basically, Physicists are trying everything.

The latter does not require the hand-wavey wishy-washy existence of an infinite number of non-observable extremely large things, and therefore garners more enthusiasm.

However, if observations conclude that the parameters of our universe are in fact paradoxically perfect, then the idea that we're an evolved observer of one chance universe out of many holds water.

Hence the intense research on how this whole universe thing works. Fun.

</comment></comment></comment><comment><USER19> When I became interested in modern physics theories of both quantum and universe level, I found the following book [0] by Max Tegmark to have very good explanations regarding origin and nature of the universe, quantum mechanics, and just interesting stories / facts from the life of physicists.

[0] [http://www.amazon.com/Our-Mathematical-Universe-Ultimate- Rea...](http://www.amazon.com/Our-Mathematical-Universe-Ultimate-Reality- ebook/dp/B00DXKJ2DA/ref=sr_1_1?ie=UTF8&qid=1409321567&sr=8-1&keywords=our+mathematical+universe)

</comment><comment><USER20> "Radical New" and "Theory" doesn't make sense, surely this would be a hypothesis :)

</comment><comment><USER11> > "Multiverse ennui cannot last forever" says Graham Ross?

That is naive. There is no way to prove or disprove it; it can be safely regarded as true without ever contradicting any possible observation we can ever make.

I do not think physics will ever settle the questions in such a way that the "multiverse ennui" is not invoked to cover the loose ends; in fact, it will become more and more obvious as the inescapable conclusion.

The deeper we dig into nature, either we keep finding more mathematics, or we encounter some absolute that can no longer be analyzed.

Once we know every physical law, and are certain nothing more is to be discovered, how do we distinguish our universe from a set of mathematical axioms? We have two choices then: to suspect there is some outer universe which implements the rules and axioms of this one. Or else admit that axioms do not require an implementation: they just are, and that's what makes their system exist (which means that any other axioms and rules we can imagine also exist just as much).

Either hypothesis is an unprovable "cop out"; but the latter of the two is more plausible. The first hypothesis still leads to an infinity of universes, and they have to be nested in each other in an infinitely regressing sequence. The second one has no such silly requirement; and it has the anthropic principle which plausibly explains everything that seems arbitrary or special.

</comment><comment><USER21> To be fair, this only kills one of the multiverse hypotheses. I'm reading Brian Greene's "The Hidden Reality" right now, and he describes about 8 independent (or semi-independent) multiverse hypotheses. From what I understand (and I'm no physicist), this just provides evidence against the anthropic principle, and the multiverse associated with that line of thinking...

</comment><comment><USER22> Someone in the comment section claims plagiarism. What's that all about?

[http://www.wired.com/2014/08/multiverse#comment-1560643455](http://www.wired.com/2014/08/multiverse#comment-1560643455)

Edit: Never mind, [http://rationalwiki.org/wiki/Mensur_Omerbashich](http://rationalwiki.org/wiki/Mensur_Omerbashich)

</comment><comment><USER23> Things like this keep me wondering if eventually we will reach a point where we are unable to distinguish theories about our own past due to lacking the energy necessary to experiment with those conditions thanks to entropy.

<comment><USER24> What does entropy have to do with anything?

<comment><USER25> If the available energy is dispersed and chaotic, we won't be able to concentrate enough to perform the experiments? Though I doubt that'll be the case at any time while the human race is in existence...

(caveat: I know very little of real physics)

<comment><USER26> If humanity lives to a point where entropy becomes a problem, I'm pretty sure our lives would be the first to go, not our "ability to perform experiments".

<comment><USER27> that entirely depends on the magnitude of the experiment.

If we were approaching any "universal energy" limitations, it'd stand to reason that our technology would be very much different than our technology now -- perhaps universe sized experiments would be feasible by that point, at which time we may hit a limit imposed on us not by anything other than the length of time since the last universe formation event, and our poor luck in meeting that point in technology at a time where the energy no longer exists to fuel it.

Unlikely, and I think your idea of life being threatened before science is probably much more rational, but it's fun to think about. Plus, if we were using that much energy for a single experiment, one would wonder about that experiments' safety.

</comment></comment></comment></comment></comment><comment><USER28> I once read that "black holes orbiting each other follow the exact same mathematics as electrons orbiting protons", but I was unable to find the direct source. I did find another article comparing black holes to elementary particles:

[http://www.technologyreview.com/view/413483/could-all- partic...](http://www.technologyreview.com/view/413483/could-all-particles-be- mini-black-holes/)

<comment><USER29> They would naturally follow the same mathematics, since the formula for gravitational attraction and the formula for electrical attraction are both following the inverse square law.

[http://en.wikipedia.org/wiki/Inverse- square_law](http://en.wikipedia.org/wiki/Inverse-square_law)

</comment></comment><comment><USER30> > Perhaps the fundamental description of the universe does not include the > concepts of "mass" and "length," implying that at its core, nature lacks a > sense of scale. This little-explored idea, known as scale symmetry, (...)

Isn't the word for that _fractal_?

<comment><USER31> Ah, no, that's a completely different sense of scale invariance. In a fractal you still have to measure the sizes of different similar structures, and generally pay attention to length. It seems that this article is discussing a much deeper abandonment of length.

</comment></comment><comment><USER11> WOBAD!

[http://www.theonion.com/articles/worlds-top-scientists- ponde...](http://www.theonion.com/articles/worlds-top-scientists-ponder-what- if-the-whole-uni,712/)

<comment><USER32> From the article:

 _" That shit would be too much," Gupta said. "It'd be like that Dr. Seuss book Horton Hears A Who and shit. I read that when I was, like, six, and it totally weirded me out."_

Nailed it.

</comment></comment><comment><USER33> Original article with less visual crap around the sides:

[http://www.simonsfoundation.org/quanta/20140818-at- multivers...](http://www.simonsfoundation.org/quanta/20140818-at-multiverse- impasse-a-new-theory-of-scale/)

<comment><USER34> Better and it doesn't have a link bait title.

</comment></comment><comment><USER35> Feels like I'm a kid and I've just been told Santa Claus is made up.

<comment><USER36> Actually it should feel more like a tall story from your uncle at a family dinner, that's not corroborated and doesn't even imply what he insists it implies.

That is, half of the article is trash and the other doesn't represent the science correctly.

</comment></comment><comment><USER37> "size differences are illusory"

So two things standing next to each other are the same size as one thing alone?

Damn hard to imagine. I would think "size" does not really "exist" but is a man made concept. And by its definition, two things next to each other form a "bigger" thing.

<comment><USER36> The article is badly written, but it doesn't really mean sizes are illusory (even if it says so at the beginning). It goes on to say that sizes and mass "spontaneously emerge" from lower interactions, which is to say, they become real for us.

But, to address your example: "So two things standing next to each other are the same size as one thing alone? Damn hard to imagine".

That might not hold for size, but a very similar thing does occur (and is proven) for speed.

If you are in a car that goes at 0.8 miles per minute, and you throw a dart that goes at 0.3 miles/minute, its speed is 1.1 miles/minute (the sum).

But if you travel at the 0.8x the speed of light and you throw something forward at 0.3x the speed of light, its speed is not 1.1x the speed of light, but c. That is, trying to add velocity doesn't get you faster than the speed of light.

[http://curious.astro.cornell.edu/question.php?number=145](http://curious.astro.cornell.edu/question.php?number=145)

<comment><USER38> > But if you travel at the 0.8x the speed of light and you throw something > forward at 0.3x the speed of light, its speed is not 1.1x the speed of > light, but c.

Not really. Velocities near c don't sum that way. And your reference doesn't support your claim.

<comment><USER39> I agree. More details: [http://en.wikipedia.org/wiki/Velocity- addition_formula](http://en.wikipedia.org/wiki/Velocity-addition_formula)

If you add two velocities that are less than c, you can never get c, you always get something smaller.

0.8c + 0.3 c ~= 0.887 c (It's smaller than c)

At low speeds the effect still exists, but it's negligible. There is an important difference between "it doesn't exist" and "it's so small that if we forget it we will be fine".

It's so small that you must use floating point numbers with too many digits to calculate it. It's more useful to calculate the difference between the "relativistic" sum and the "classical" sum. Another way is to aproximate the formula with a Taylor expansion

dif = (X+Y) / (1+(X * Y/c^2)) - (X+Y) ~= - (X + Y) (X * Y/c^2)

0.8mph + 0.3 mph = 11mph - 5.9 * 10^-39 mph

The correction is veeeeery small.

<comment><USER38> > The correction is veeeeery small.

Indeed it is. The only place I can think where such a small correction matters is in the GPS system. The accuracy of the GPS system depends on tracking down and eliminating every possible source of error, and to maximize position accuracy, two relativistic effects are accounted for:

1\. The time dilation caused by the satellites' velocity, from Special Relativity.

2\. The rate of time passage at orbital altitude compared to that at the surface, which reflects the gravitational well effect of General Relativity.

The two effects move in opposite directions, but they don't cancel out. The applied correction (to the orbiting clocks) is very small indeed, but enough to avoid a gradual but serious decline in positional accuracy over time.

<comment><USER40> Does anyone know of a general & special relativity simulator? That is, a program where I can setup various "thought experiments", by placing clocks and masses at various point in space, where they can have various acceleration profiles, and can communicate with each other, and run the scenarios? I never really understood the twins "paradox" and the explanations for the source of the asymmetry seemed hand-wavy and "because".</comment></comment></comment></comment></comment></comment>


The Nazi book of anatomy still used by surgeons - <AUTHOR> https://www.bbc.com/news/health-49294861 <comment><USER2> Whether it comes from Nazi or what else, if the diagrams and information and so on is good for this use, then it is good.

</comment><comment> m-p-3 I'm torn between its use.

In a way, the Nazi acquired this information in an unethical manner, so using it is unethical.

But in another way, the information acquired, even if it was done unethically. It can save lives or increase our understanding of our biology, and not using it would make all the people who suffered and/or died for it to be in vain. We also cannot undo the past.

Who shouldn't forget all the atrocities the Nazi did at the risk of repeating history, but we shouldn't put aside any findings that can be used for the benefit of everyone else.</comment>