Facebook is using D in production starting today - <AUTHOR> http://firstname.lastname@example.com <comment><USER2> For an excellent discussion between the philosophies that went into the design of D and how they compare to Go, visit

      https://groups.google.com/forum/#!topic/golang-nuts/8k59RgkeJ6s

The discussion between Andrei Alexandrescu (Facebook) and Ian Lance Taylor (Google) is highly intellectual, especially the part about how each language addresses concurrency.

EDIT: Removed dot at the end of the URL

<comment><USER3> The most important Andrei's quote:

"D has resolutely exited C++'s shade because it is good at things C++ is not good at, in addition to being good at things C++ is good at. Also, Go would be tenuous to frame as a better C because it cannot do everything C does - e.g. unsafe memory access and manual memory management, which are needed in certain systems - and it interoperates poorly with C."

In short, he states that D can do unsafe memory access and manual memory management. Go can't.

<comment><USER4> Sounds like D would be better-compared to Rust, then.

<comment><USER5> D is more like C++ without macro and with GC plus some engineering features (unit test is a language feature? weird). Rust looks different and does different. For example, idiomatic foreach block in Rust is a syntax sugar of passing lambda, which is more friendly to parallelism. While in C++/D it is a syntax sugar of classic for-loop with iterator, which is more efficient in unparalleled environment.

<comment><USER6> _> For example, idiomatic foreach block in Rust is a syntax sugar of passing lambda, which is more friendly to parallelism_

This changed with the recent 0.8, `for` is now syntax sugar for using the Iterator trait, which optimises exactly like C++ (the vector iterator even vectorises when LLVM can do it).

Rust has actually moved to have iterators that are very similar to (a subset of) D's ranges.

</comment></comment></comment></comment></comment><comment><USER7> For one example of a D program in production use, check out [http://forum.dlang.org](http://forum.dlang.org). The forum software is entirely written in D (written by Vladimir Panteleev).

(Although due to this announcement, the site is being slammed at the moment. It's a single server hosting dlang.org, not a farm.)

<comment><USER8> The responsiveness of this forum is amazing. Is the client side doing some pre-fetching?

I remember finding the website disturbingly fast on my first visit. I wonder if it is just me being so used to loading delays, or if there is a point were you can be so fast that it is detrimental to the user experience. The latter doesn't sound like it makes sense so it must be of matter of getting used to it.

<comment><USER9> Well, a forum is essentially the same thing as BBSs were in the 80s but now we have computers that are several thousand times faster. I find it much more "amazing" that the other forums are so slow.

<comment><USER10> BBSs in the 80s / 90s were operated by users in their own homes and usually weren't allowing for multiple connections. The software itself was pretty dumb and slow.

Forums these days need to allow for multiple users to log in, read content and post messages. I'm pretty sure that the link above received several hundreds or thousands of users in a single hour. Forums these days also use database systems (or other services external to the process) that represent a big bottleneck. Then you've got the issue of static assets, like CSS, Javascripts, images and so on.

As a general rule of thumb, if you want scalability, you have to trade some throughput for it, as scalability concerns hurts performance.

That said, popular open-source web software, in general is awful in terms of everything.

</comment></comment></comment></comment><comment><USER7> The D project code is entirely on github:

[https://github.com/d-programming-language](https://github.com/d-programming- language)

Naturally, contributors are welcome!

</comment><comment><USER11> Facebook seems to use any language they want to at any time. I don't consider it a major endorsement that it appears in production, it just lets me know its on their radar.

If Google picked up D I would be much more interested as to why.

<comment><USER12> Having D used in production in a big company like Facebook is a big deal. No, it doesn't mean that D has taken over the programming world or anything like that, but it shows that the language is maturing and that real companies are now willing to use it in the real world - and it's a pretty major company at that.

So, this is just one step forward, but it's a big one and exciting to the folks who are fans of D - especially those who have put a lot of time and effort into it.

<comment><USER13> Might have as much to do with the persuasive powers of Andrei Alexandrescu as the maturity of D.

</comment></comment></comment><comment><USER14> I'm really interested why D doesn't get much love from C/C++ devs.

<comment><USER15> I knew when I was a C++ dev that any "other languages" was just not serious. Lots of friends who are master in C++ call everything else than C and C++ "scripting languages". I was in that closed-mind ecosystem of C++ elitist but then, luckily, I learned about Python and it caught my interest.. and then from there I've learned Lisp, Ruby, Javascript, etc etc. And I haven't touched C++ after that.

Note that I live in a startup environment all the time and the time and cost to develop in C++ is just _too damn high_ for me. Also, the verbosity and its philosophy kills me.

What was it?

        std::map<int, std::vector<int>> whatever = new std::map<int, std::vector<int>>();

Why not

       d = {}

<comment><USER16> C++11 brought type inference so these days it would be either

        auto whatever = new std::map<int, std::vector<int>>();

or

        std::map<int, std::vector<int>> whatever;

depending on if you want heap or stack allocated variable, stack allocation usually being preferred as the default solution (and thus being the tersest form).

But lets look a bit deeper why C++ is more verbose in this case. One central reason is the idea that standard library should not be special/privileged in the language syntax. The upside from that is that almost all syntax sugar can be applied to user defined types. A relevant example would be uniform initializer lists in C++11, which allow you to write eg.

        std::vector<int> foo {1,2,3};

but also

        MyFunkyDatastructure bar {1,2,3};

as long as suitable constructors are defined. In comparison afaik in Python you can not define a class that can be initialized with sugared syntax.

The theme of non-privileged standard library also extends to global namespace pollution. In C++ stdlib does not get to reserve names at global namespace, which leads slightly increased verbosity (std:: -prefixes or using- statements).

So when you ask why you cant make a map/dict in C++ with just 'd = {}', know that there are actually good reasons for (some/most) of the verbosity. The tradeoffs might make it less suitable in your usecases, but there is no absolute/general superiority in either way.

<comment><USER15> >> know that there are actually good reasons for (some/most) of the verbosity.

This is why I talked about the philosophy of the language. I wasn't arguing about whether it was good or bad.

That being said, for my own use cases, verbosity is a big deal.

>> In C++ stdlib does not get to reserve names at global namespace, which leads slightly increased verbosity (std:: -prefixes or using-statements).

I understand and agree, but you'd have to agree with me that if you start naming your classes Map and Vector, you're looking for problems ;-)

</comment></comment></comment></comment><comment><USER17> Really interested to know what other compile-to-native-code languages that they evaluated and why they chose D over other alternatives. Anyone knows if such comparison is available?

<comment><USER18> Andrei is a well-known member of both the C++ and D communities; he's probably #2 after the language's creator, Walter Bright.

So I'd imagine it has something to do with said expertise.

</comment></comment><comment><USER19> I remember having a chat with Andrei, one of D's creators, almost one year ago and saying: "If you want D to be more popular, maybe you should make an announcement about Facebook using D internally". Seems that day is here :)

<comment><USER20> But 1 year ago, facebook was popular than today ;-)

</comment></comment><comment><USER21> For anybody wondering how D compares to Go, have a look at [http://stackoverflow.com/questions/3554956/d-versus-go- compa...](http://stackoverflow.com/questions/3554956/d-versus-go-comparison)

<comment><USER22> Easy,

Go is targeted for developers that can move out of C in their use cases.

D is targeted for developers that can move out of C++ in their use cases.

<comment><USER23> Except that the go developers explicitly stated their design goal was to replace C++ for their needs, not C. And that completely failed, and now the focus is on pulling in python devs.

<comment><USER22> I jumped into Go bandwagon early on, even tried to do some initial contributions. Mostly because Go has an Oberon feel to it. A GC enabled systems programming language I used for a while in the mid-90's.

However, I quickly became disappointed with Go's spartan design, given my broad experience across languages and paradigms.

That is why somehow I feel it is more indicated for C developers, that could live with a GC enabled language.

As they would mostly getting type safety and a few more features, whereas developers from other languages are mostly giving away features.

</comment></comment></comment></comment><comment><USER24> > Today I committed the first 5112 lines of D code to Facebook's repository.

> The project is in heavy daily use at Facebook

So, they had code under heavy use which was not under source-control?

<comment><USER25> The way I read it is that he added some D code to an existing C++ project's repo.

</comment></comment><comment><USER26> Between D, Nimrod and Julia it looks like there's a resurgence of fun in (JIT) compiled languages.

<comment><USER22> All available D compilers generate native code directly, there is no JIT involved.

Sometimes I wonder how computing would look like if the default implementations of Java and C#[1] were available from the start as native compilers, instead of VM environments.

[1] Funny enough, the precursor of .NET was native and COM based, similar to what is now WinRT, more info here,

[http://blogs.msdn.com/cfs-file.ashx/__key/communityserver- co...](http://blogs.msdn.com/cfs-file.ashx/__key/communityserver-components- postattachments/00-10-32-72-38/Ext_2D00_VOS.pdf)

<comment><USER27> _Sometimes I wonder how computing would look like if the default implementations of Java and C#[1] were available from the start as native compilers, instead of VM environments._

At least with Java that would defeat one of the main intents of its development. What would you think would be gained by having non-VM based implementations of these by default?

<comment><USER28> Start up time. You can't write cli programs if the JVM takes 100+ms to start up.

<comment><USER29> How do webservers solve this problem and why can't CLI programsw do the same? Invoking a Java program could connect to a running jvmd daemon

<comment><USER27> They "solve" it by being long running applications. When GP says CLI they likely mean things like grep or cat or other command line tools, not just interfaces, that tend to run in a very short time. A Java implementation would see a lot of extra time spent on just the startup. Consider writing a bash script that calls out to grep for each of a bunch of different files (an example, better ways, but go with it). Say it ran grep 100 times, jgrep at 100ms startup time would take 10s longer just on the java startup time, ignoring any other performance differences.

</comment></comment></comment></comment></comment></comment><comment><USER30> Biggest advantage of D synchronized functions as a lang feature.

</comment><comment><USER31> Apple has Objective-C, Mozilla has Rust, Google has Go, Microsoft has C#. I wonder if Facebook was feeling a little left out of the post-C++ language party?

<comment><USER32> One of these languages is not like the others.

<comment><USER33> None of these languages are like the others.

<comment><USER34> I believe they're referring to syntax, in which case, Go is rather unlike the others.

<comment><USER35> No, I think he's referring to C# which runs on a VM.

You couldn't write an operating system, or realtime code in C#.

It's not even in the same league as the other three, and would be better compared to Java.

<comment><USER22> > No, I think he's referring to C# which runs on a VM.

This is not true. The CLR is just one of many C# implementations.

Mono provides a native compiler for C#.

Bartok is a native compiler for C# from Microsoft Research.

> You couldn't write an operating system, or realtime code in C#.

Except people have already done it in the past.

[http://research.microsoft.com/en- us/projects/singularity/](http://research.microsoft.com/en- us/projects/singularity/)

[http://research.microsoft.com/apps/pubs/default.aspx?id=5271...](http://research.microsoft.com/apps/pubs/default.aspx?id=52716)

[http://singularity.codeplex.com/](http://singularity.codeplex.com/)

[http://cosmos.codeplex.com/](http://cosmos.codeplex.com/)

> It's not even in the same league as the other three, and would be better > compared to Java.

Similarly to Modula-3, C# has all the required low level capabilities for systems programming with unsafe blocks and annotations.

It should be compulsory for everyone to learn about compiler design, before comparing programming languages.

<comment><USER35> Fair enough. I should have specified CLR instead of C# in general.

That said, I stand by my argument that it is better compared to Java, though the later revisions have been adding more C++-esque low level features. I find C# a good compromise.

> It should be compulsory for everyone to learn about compiler design, before > comparing programming languages.

My oversight, and difference of opinion with you does not mean I'm an uneducated idiot. I wrote a (limited) C compiler in my undergrad and programming languages was large mandatory portion of 4th year. If you rear- ended somebody on your morning commute, I'm not going to assume you're a dangerous driver and should be pulled off the road.

This is Hacker News - not Reddit. The least we can do is act like that means something.

</comment></comment></comment></comment></comment></comment></comment><comment><USER36> Does D have anything to do with the client-side? All this morning, the browser tab keeps crashing whenever I load facebook in chrome.

<comment><USER36> Safari seems to load fine. I have a OSX 10.8.4 and Chrome 27.0.1453.110

</comment></comment><comment> shawn-butler Congratulations. What is the status of workable compiler and standard library on ARM?

</comment><comment><USER37> Facebook loves the D</comment>


scala-zeromq - thread-safe ZeroMQ sockets for Scala - <AUTHOR> https://github.com/mDialog/scala-zeromq

<comment><USER2> The 0mq extension included with Akka has serious design problems, so I'm happy that mDialog has let us open source this. (I didn't write it, but I've worked on issues we've had using the original Akka extension). The Akka actor wrapping each 0mq socket sends itself a message to trigger a poll, which blocks for a configurable period of time. Messages easily queue up both in the actor's mailbox and on the 0mq socket. The default settings for the extension leave you with very high latency and poor throughput, but even if you modify the polling frequency and timeout you end up trading heavy CPU usage for what ends up being increased but still capped latency and throughput improvements.

</comment><comment><USER3> This is awesome, wish it'd been there a week earlier!

You should try to get it included on the official zeromq site: <http://www.zeromq.org/bindings:scala-binding>

</comment><comment><USER4> Getting a "Sorry, this tree took too long to generate." from Github on this project. Was working fine earlier, what gives?</comment>


A Spreadsheet for finding Roots of Polynomials - <AUTHOR> https://datanitro.com/blog/2013/7/9/spreadsheet_for_polynomial_roots/

<comment><USER2> _" If you change a polynomial's coefficients slightly, its roots will only change slight as well."_

If only: [http://en.wikipedia.org/wiki/Wilkinson's_polynomial](http://en.wikipedia.org/wiki/Wilkinson's_polynomial)

<comment><AUTHOR> That's a great point, and an awesome article. In the post, I'm referring to a continuous change versus a discontinuous one; with large coefficients or large powers, you can cause a big shift with a very small change.

However, you can always find a chance small enough that it won't make a substantial impact on the roots; this isn't the case with discontinuous functions.

<comment><USER3> Ehm. The big (as in BIG BROTHER) problem is that mere continuity is a very very weak property. The fact that "small" changes turn into other "small" changes depends essentially on the "smallness".

For example (I know this is not a polynomial, but the function is related to root-finding):

f(x) = x^(1/10)

which has x=0 as a root (f(0)=0).

Take a "small" increment of x, say x=0.01

f(0.01) = 0.63+

Which, to any reasonable human being is "quite large" with respect to the increment of x.

This is even worse for Wilkinson's Polynomial, which is what the parent was trying to convey, I guess.

I know I am referring just to a related problem but this is one of those days for me...

That is: roots depend _continuously_ on the coefficients of a polynomial but that _continuity_ is filled with very bad behaved constants all around dancing and whirling to make the problem very very bad behaved.

EDIT: I think I have realised what I want to say.

Take P(x) = x^10, it has a (multiplicity 10 root at x=0). Then take Q(x) = x^10 - .01 (which is a "small" deformation of P(x)). Then the roots of Q are 0.63+ and -0.63+, which are "huge" compared to 0, 0.01.

Unless I am still under this terrible drosiness...

<comment><USER4> The dependence of (real) roots on the coefficients of a polynomial isn't even continuous; an arbitrarily small change to the coefficients of a polynomial with a double root will result in either the appearance of an extra root or in the (real) root disappearing entirely.

In the complex plane the situation is much happier, but root-finding remains extremely poorly conditioned for examples like Wilkonson's.

<comment><USER3> Yes, yes, I know that, I was focusing on getting an example.

I think I should call it a day and reboot tomorrow...

</comment></comment></comment></comment></comment><comment><USER5> Section 3 "Roots are closely related to factoring a polynomial - for example, the roots of x2 - 4 are 2 and 2, and you can write x2 - 4 as (x-2)(x-2). We say that a root r has a multiplicity greater than one if (x-r) is a factor of the polynomial more than once." This is incorrect. x2 - 4 = (x - 2)(x + 2). Meaning the roots are 2 and -2. Also section 5, I'm not sure how you came up with those answers. The roots are 2 and -1. I tried the spreadsheet, but can't seem to get it to work.

<comment><AUTHOR> these are fixed. thanks for pointing them out!

what's wrong with the spreadsheet?</comment></comment>


Create QR-code landing pages for business or personal use - <AUTHOR> http://scan.me/qr-code-generator/

<comment><USER2> We've been working for awhile on this - would love to hear some feedback from the Hacker News community.

</comment><comment><USER3> Far too much focus has been spent on the QR codes rather than the content or experience behind the code. QR code technology works...done and done...now let's move on the the next stage: mobile friendly landing pages for business or personal use.

</comment><comment><USER4> cool. Clean design. Thanks for the share.</comment>


Fructan, not gluten, induces symptoms in patients with gluten sensitivity - <AUTHOR> http://www.gastrojournal.org/article/S0016-5085(17)36302-3/pdf <comment><USER2> I had a 3-year span where I could not eat gluten, and for 1 year of that I could not eat corn. My level of sensitivity was such that I could not eat gluten-free meals at any restaurant due to cross contamination nor drink instant coffee because the conveyors are sprayed with a corn-based anti- clumping solution.

I saw 3 different digestive specialists (I believe all gastrointestinologists, it's been a few years). Their approaches did nothing. Then I searched for digestive disease research centers, went to one, and was "cured" after two visits. The doctor said that my situation is becoming more prevalant, and that the issue is typically one or more of the following: A hostile bacteria in the digestive tract, overgrowth of one or more bacteria in the digestive tract, or a parasite.

A round of the following two drugs fixed me within a few days: Alinia and Neomycin. I was drinking beer and eating noodles again without any problems.

Now I have to take an antibiotic that targets the digestive tract every 1 - 1.5 years as symptoms return. This indicates that my problem is bacterial rather than parasitic, although the exact cause of my problem hasn't been identified.

An interesting side note: I traveled to Japan while affected by gluten (but before corn became problematic), and I ate in restaurants the whole trip with only one problem. I am certain that I was consuming small amounts of gluten with each meal. I learned that Japan and other countries have rejected US wheat shipments over certian GMOs, but I couldn't reliably explain why I was largely unaffected in Japan.

<comment><USER3> miek, I'd really appreciate if you could contact me with more precise information (analysis you did, etc...).

I've been struggling with gluten sensitivity for 1.5yrs (been through the gastroenterologist circuit already, with 0 results) so your comment blew my mind.

Thank you! My email: chris [à] chris-hartwig.com

<comment><USER4> Hi, I had "gluten sensitivity" for maybe the last decade. Brain fog, fatigue etc. removing gluten helped but did not fix. Then I tried the ketogenic diet and all my problems went. Infact I feel better then I have ever in my life when in a state of ketosis. Not sure of the reason - It could be I'm cutting out a certain foods.. or it's the anti inflammatory effects of ketone bodies? Still searching for answers on why. But for now it feels like I've been given a second chance at life.

I'd be happy to provide more details to you if your interested in trialing this path.

<comment><USER5> Not sure why you're being downvoted.

If there's one thing I've learned, when researching how diet can affect myself, it's that different humans react to different food types and intake, in different ways.

If a ketogenic diet works for you, the same diet may not work for others. Similarly, other types of diet may not work for you.

It's for that reason I decided to vote you up again - there is no reason to downvote what you posted.

One particularly enlightening book which changed my outlook on diet, raised an eyebrow, and just clicked with me, was "Eat Fat and Grow Slim", written in 1958 by Richard Mackarness, M.B.,B.S.

<comment><USER4> 1958.. The more you dig into th history of nutrition the more you realise there was two parallel tracts. The one that won public opinion (low fat/high carb) has pretty much contributed to an epidemic. Recommend the book "the big fat surprise" by Nina Teicholz on the topic.

</comment></comment></comment></comment></comment><comment><USER6> There are a ton of theories out there that the gluten sensitivity is something other than for gluten, but just a big correlation.

I'm pretty convinced by the literature that gluten sensitivity isn't really a "thing" outside of celiac disease, but even with me, I have problems with painful acne breakouts when I eat gluten, that don't happen when I don't have gluten. And from doing some googling and informal surveying of friends, it seems I'm far from alone on that.

Now is that because of gluten itself? Who knows. Maybe it has to do with how wheat is processed these days, or something else. It's really frustrating that something so basic and common doesn't seem to have any scientific answers, though.

<comment><USER7> My pet theory is that people are sensitive to the glyphosate sprayed on most wheat, not the actual gluten.

<comment><USER8> People spray glyphosate on wheat?

Glyphosate is typically used in conjunction with "Roundup Ready" crops, or before/during planting in "no-till" crops. While Monsanto developed a Roundup Ready line of wheat, it never actually made it to market, AFAIK, so why would you be spraying glyphosate on wheat?

(Serious question; while I have some background in agriculture, I'm not familiar with all of even the common practices.)

ETA: Reading the Snopes link, looks like it's mainly practiced in North Dakota, which explains why I've never heard of it.

<comment><USER9> It's not practiced in ND out anywhere else. The export market won't accept it and it's not deliverable against spring wheat futures so it's not marketable and never has been.

</comment></comment></comment></comment><comment><USER10> I'm not a statistician, but the results section is worth reading -- the fructan results are not much higher than placebo but both placebo and fructan are more affective than gluten.

"Overall GSRS-IBS scores differed significantly during gluten, fructan, and placebo challenges; mean values were 33.1±13.3, 38.6±12.3, and 34.3±13.9, respectively (P = .04). Mean scores for GSRS bloating were 9.3±3.5, 11.6±3.5, and 10.1±3.7, respectively, during the gluten, fructan, and placebo challenges (P = .004). The overall GSRS-IBS score for participants consuming fructans was significantly higher than for participants consuming gluten (P = .049), as was the GSRS bloating score (P = .003). Thirteen participants had the highest overall GSRS-IBS score after consuming gluten, 24 had the highest score after consuming fructan, and 22 had the highest score after consuming placebo. There was no difference in GSRS-IBS scores between gluten and placebo groups."

<comment><USER11> if placebo is a sugar pill, maybe it's a sugar sensitivity...

<comment><USER12> I assume placebo is the same muesli bar used in the other groups (without the supplemented fructan or gluten).

<comment><USER13> Ah! Excellent point!

</comment></comment></comment></comment><comment><USER14> FWIW, I've been sensitive to gluten for years, but when I traveled in Spain -- I was fine. Then I came back to the US, and tried wheat again. Nope.

I would not be surprised if the way we're processing / spraying our wheat here is giving some folks problems.

<comment><USER15> I would similarly be unsurprised if there is just some other factor. I saw an article onetime that showed a link between alergies to apples and the range of an unrelated tree. That is, there was some other type of tree that, if present, increased the occurrence of reported allergies to the apple. Whereas the same apple in a location without this tree had fewer allergies reported.

Sadly... my inability to refind this article makes me suspect that, though I may be unsurprised by this idea, I have no evidence for it. So, if anyone can help refute the idea, that would be great! :)

<comment><USER16> You may be thinking birch trees. I'm allergic to certain raw fruits (cooked or canned ok), beans, and tree nuts (peanuts and cashews ok). I'm told this weird combination is a thing.

I found "Oral allergy syndrome" [http://acaai.org/allergies/types/food- allergies/types-food-a...](http://acaai.org/allergies/types/food- allergies/types-food-allergy/oral-allergy-syndrome)

<comment><USER15> Thanks for the link! That at least makes it look like I didn't imagine the article. The one I remember was a more direct link between allergies to thing X, but only in the presence of thing Y. With no reported allergies to thing Y.

</comment></comment></comment></comment><comment><USER17> I can confirm this was the case for me. After months of testing I was considered "not gluten sensitive", while experiencing bad IBS when consuming gluten. Once I tried the FODMAP diet I found that the food should high in fructans were my trigger.

<comment><USER18> Looked that up, sounds perhaps like a harder diet than gluten free. Giving up onions and garlic, plus pasta, bread, etc...ouch. You have my sympathy.

<comment><USER19> Ideally you should use FODMAP as an elimination diet to determine what food's you react to. I went though it a couple of years ago and discovered that onions (and large amounts of garlic) will give me IBS symptoms. I'm fine with everything else on the FODMAP list. I know others that have discovered they are sensitive to fruits such as apples, pears, etc.

I don't know anyone who has stuck to a strict FODMAP diet long-term.

<comment><USER20> I know someone who has, but that was because it helped manage her auto-brewery syndrome. Pretty much any time she ate off-diet she immediately regretted it the next day, so that was _very_ effective at keeping her honest.

</comment></comment></comment></comment><comment><USER21> ..oh. elsevier.

[https://www.ncbi.nlm.nih.gov/pubmed/29102613](https://www.ncbi.nlm.nih.gov/pubmed/29102613)

<comment><USER22> What do you mean?

<comment><USER23> The OP means that the publication appears in one of the Elsevier journals, and the link goes to an Elsevier-affiliated website.

The OP provided a link that doesn't go to an Elsevier-affiliated website.

Elsevier is an academic publisher that is a relic of a pre-digital world. Essentially, it leeches on universities, charging money for access created by academics,funded by the state, and peer-reviewed by volunteers for free. They justify their need to charge money by reasons such as hosting costs, but whenever someone tries to host their articles for free, they pull out the big guns.

Such actions, in particular, led to death Aaron Schwartz (see [https://en.wikipedia.org/wiki/Aaron_Swartz](https://en.wikipedia.org/wiki/Aaron_Swartz) ).

Elsevier is not liked around here.

Speaking of resources that anger Elsevier by hosting articles for free, Sci- Hub is one. In particular, you can read the full text of the article by going to [https://sci-hub.cc/](https://sci-hub.cc/) and looking up the paper's DOI (10.1053/j.gastro.2017.10.040).

This full text is not available for free on the original publication link (nor on the NIH website). The study was funded by: the Extra Foundation Health and Rehabilitation, the Norwegian Celiac Association, the Throne Holst Foundation for Nutrition Research and the Wedel Jarlsberg Foundation - neither entity being Elsevier. (You can find this in the paper once you pay Elsevier to access it).

So yes. Oh, Elsevier.

<comment><USER22> But what does the link help?

<comment><USER24> "The OP provided a link that doesn't go to an Elsevier-affiliated website."

<comment><USER22> Yes, what does that achieve?

<comment><USER25> Did you apply your moniker to yourself? [For the rest of the world: _Bromskloss_ is Swedish for brakepad]. The link achieves access to the article without driving traffic to the parasites at Elsevier.

<comment><USER23> Hah, interesting. _Brake pad_ is a mild insult in Russian, used in the same way _slowpoke_ is used in English online these days.

I've always wondered which languages use _brake pad_ (or any part of the braking mechanism) in the same way.

<comment><USER25> Yes, interesting, thank you. I've never _heard_ bromskloss used that way in Swedish, but then, I'm Danish, and don't really know this neighbouring language from the inside.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER26> I could never pinpoint what foods caused trouble for me until I was an adult. Turns out I have (what I call) an intolerance to canola oil. No allergic reaction, but serious digestive trouble / etc. And it can be in _anything_. Different production runs of the same brand of crackers can use different oils so it is nearly impossible to identify unless you stumble upon it by accidentally fasting due to flight problems and just making hashbrowns (potatoes and canola) at your destination as a snack. I had accepted it as a fact of life until eliminating it from my diet, and lo and behold, food is always awesome.

</comment><comment><USER27> My theory is that we have hybridized and bred strains of wheat in the West which have caused these problems.

An interesting study would be take some "old world" wheat (that has not been impacted by the industrial-scale farming practices of the West), and see if the gluten-sensitive people still have the same reaction to that.

</comment><comment><USER28> Thank you for sharing the link to the actual summary.

N=59 which is enough to justify for a larger survey but probably not to garner the attention this piece is receiving.

This will trigger massive swings in how certain food groups are perceived, affect farmers, etc. Caution is required.

<comment><USER3> Science is science, not politics, and it must stay that way.

A french wheat producers syndicate has published web pages to say even coeliacs should eat gluten, just less of it... That's even the first article my mom found about gluten intolerance and she called me to tell me gluten intolerance isn't really a thing according to the internet. My guts and my gastroenterologist both disagree.

That's what happens when you listen to politics and silence scientists.

</comment></comment><comment><USER29> There is an app which might be useful for anyone undertaking or starting a FODMAP elimination diet called Monash Uni Low FODMAP Diet. No affiliation; we just found it very helpful to classify ingredients and for recipe ideas while we were new to the process.

</comment><comment><USER30> Fructan is, if I trust internet definitions, a fructose polymer. Perhaps fructan sensitivity is an immune/whatever reaction to high fructose corn syrup, mis-directed at fructan due to its similar composite materials.

<comment><USER31> This study was done in Norway. HFCS is pretty rare in Europe compared to the US. It's possible that it was present in the "fructan" treatment here, but if I had to bet, I'd bet it was unlikely.

<comment><USER32> Although the study isn't about the FODMAPs generally, note that fructose itself is also a FODMAP (when present in larger quantities than glucose), and so could also cause similar symptoms.

</comment></comment></comment><comment><USER33> I think the paper focuses only in gastrointestinal symptoms. NCGS actually causes more extra-digestive problems than the classic Celiac disease ones. Before I started my very strict gluten free diet I had migraines, fatigue, joint pain brain fog... I continued eating lots of fructans, especially garlic an onion, but I still improved dramatically. My thyroid, inflamation and cholesterol markers went back to normal. My rheumatologist Carlos Isasi has done extensive work about it and even published a study about a big % of fibromyalgia patients improving a lot by avoiding gluten. So, I don't believe it is all about fructans. I think it is related, though. My theory involves archaea overgrowth, pyrrolisine use for methane production (here comes the gas and IBS symptoms) and leaky gut as a result letting gluten into the bloodstream (which causes the toxic immune response)

</comment><comment><USER34> Just looking at the abstract, does anyone know what the typical values for that questionnaire of GSRS-IBS would be? Is it a mean of near 0? I would want to see a control group, different notion than a placebo, which has no self- reported problems and see what kind of variety there is in the scoring.

</comment><comment><USER35> 59 subject divided into three groups - is that even statistically relevant?

</comment><comment><USER36> Maybe. U need a Lectin blocker. Have u looked at lectin in foods?

</comment><comment><USER36> Lectin in foods? Maybe u need a lectinblocker?</comment>


My Favorite Science Fiction (and Non-Fiction) Books - <AUTHOR> http://compellingsciencefiction.com/blog/2016-12-18.html <comment><USER2> I'll counter with:

1) Dune - Frank Herbert

2) Mote in God's Eye - Niven & Pournelle

3) The Lord of Light - Roger Zelanzy

4) Xeelee Series - Stephen Baxter (Or the Manifold: books)

5) The Well World Saga - Jack L. Chalker (Stick with the first 5 books)

<comment><AUTHOR> Thanks, I haven't read 3-5, I'll definitely check those out! Dune is incredible, although it always felt a little too much like epic fantasy for my tastes.</comment></comment>


Will We Ever Know What Dark Matter Is? - <AUTHOR> http://cosmos.nautil.us/feature/133/will-we-ever-know-what-dark-matter-is <comment><USER3> I don't think we will ever know the answers to fundamental philosophical questions such as why or how the universe exists.

However, dark matter is measurable physics. I'm sure if technology and knowledge keep getting better we'll be able to solve this one, but it won't help with the aforementioned fundamental philosophical questions.

<comment><USER4> The how is likely just another question of physics; I recall watching some PBS special that hypothesized some collision of higher-dimensional branes.

<comment><USER5> So how do these branes exist? The fundamental question remains.

<comment><USER6> I don't think the fundamental question is how these branes exist.

The fundamental question is: what's the most basic truths that we can ever know?

If there are hyperdimensional branes the likelihood is that we wont be able to learn much about their origins because of their relationship to our universe. An acceptable answer then becomes "We can't know how they exist..."

</comment></comment></comment></comment><comment><USER7> Most people like to think that science is all about sharing information and that the popular theories are as far as mankind has come to understand the universe. Sadly this is not true. For every scientific discovery which has the potential to be used as a weapon, there will be forces trying to keep it hidden.

Instead of looking forward, it may sometimes be more productive to look backwards - especially pre-Einstein. James Clerk Maxwell and his luminiferous aether is as good as theory, if not better, than any modern explanation about what's out there. He even provided us with the math describing it (though is was removed later on).

The years after, towards the end of the nineteen century, is full of scientists claiming incredible discoveries - like anti-gravity, free energy, wireless transfer of information as well as power, apparatus for remote viewing and more. Nikola Tesla being the most famous I guess. Think how different the last hundred years would have been if any of it had reached the public domain.

On the other hand; making an atom bomb isn't really that complicated (the difficult part is surviving doing it). If every person you know had one, that would probably not work out. My point being that there are arguments for keeping information restricted. Put capital in the mix and it's bound to be some collusion.

Imagine you had a grid of antennas and that you could adjust the phase and frequency of each as to get the signals from all of them to be in-phase at a specific point. Everyone visiting this site could probably think of a handful of ways to do exactly that. Then imagine you had a lot of antennas and a lot of juice - you could more or less focus an insane amount of energy wherever you wanted on this planet without anyone being any wiser. What would you do with a power like that? Would you share?

<comment><USER8> > James Clerk Maxwell and his luminiferous aether is as good as theory, if not > better, than any modern explanation about what's out there

No, it's a disproven theory that has been superseded by the far more elegant notion of Lorentz symmetry.

> The years after, towards the end of the nineteen century, is full of > scientists claiming incredible discoveries

Cranks are a constant presence.

> Imagine you had a grid of antennas and that you could adjust the phase and > frequency of each as to get the signals from all of them to be in-phase at a > specific point.

I look forward to the calculation here!

</comment></comment><comment><USER4> My favorite pet theory (head-canon may be a more appropriate term) is that Dark Matter is a set of matter that's just as rich and interactive as ours - made up of particles that follow the analogue of our laws, with weak, strong and electromagnetic forces - but slightly different, so that _that_ parallel universe is full of intelligent life, investigating "shadow matter" that only interacts via gravity, wondering how sad and empty and dark it must be for those particles that make up only 10% of the universe.

<comment><USER9> If it interacted with itself in ways other than just gravity, it would make clumps. The problem is, it doesn't make clumps. Its distribution is very clearly non-clumpy.

Also, if this was gravity leaking between parallel universes, I believe it would produce measurable artifacts, and therefore could be tested.

<comment><USER10> Can we say it doesn't clump or can we only say it doesn't clump on the galactic scale? Could it clump but then go into it's equivalent of a super nova with very small clumps?

<comment><USER11> This is a pretty good question.

There is a limit to the changes in the momentum of cold dark matter before it produces visible effects in galaxies of different ages. Explosive processes in the dark matter sector must be rare, whatever their mechanism and whatever their daughter products (even if it quickly decays to cold dark matter again, but on a different trajectory).

</comment></comment></comment></comment><comment><USER12> I like to look through the lens of quantum field theory instead of 'particles'.

Dark matter may be some field or interaction of existing fields that we don't understand yet.

</comment><comment><USER13> Yes, up to now there's nothing directly detected, but we should also not forget that just two years ago a pessimistic article could have been written about the detection of the gravitational waves, this is how it could have looked like: "predicted 100 years ago, never detected, even if there was some investment in the detectors and specific scientific work for 40 years, and in spite of some indirect evidence." It is also easy imaginable somebody claiming that LIGO shouldn't be funded only to "measure the change of a 4 km length in a tiny fraction of the size of a single proton."

But then... hundred years after the prediction, the magnificent thing did happen:

[https://en.wikipedia.org/wiki/First_observation_of_gravitati...](https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves)

And then another one:

[https://en.wikipedia.org/wiki/GW151226](https://en.wikipedia.org/wiki/GW151226)

</comment><comment><USER14> Have we already ruled out the possibility of dark matter just being huge numbers of black holes without notable accretion disks?

<comment><USER15> Not completely, but seemingly unlikely.

[http://resonaances.blogspot.ch/2016/06/black-hole-dark- matte...](http://resonaances.blogspot.ch/2016/06/black-hole-dark-matter.html)

<comment><USER14> Thanks for the link. Just found this one from NASA as well: [https://www.nasa.gov/feature/goddard/2016/nasa-scientist- sug...](https://www.nasa.gov/feature/goddard/2016/nasa-scientist-suggests- possible-link-between-primordial-black-holes-and-dark-matter)

So, it seems like it's still an open possibility, and even better, it might be resolvable one way or the other in the near future -- at least for the primordial black hole hypothesis.

</comment></comment></comment><comment><USER16> Having just finished reading Lisa Randall's "Dark Matter and the Dinosaurs," I was a bit disappointed to not see any mention of her new "dark disk" hypothesis. Maybe her research is a bit more "fringe," but it seems like all of these experiments are pretty far out there.

The "dark disk" hypothesis basically says that there are actually multiple types of dark matter particles, and there's a disk made of heavier or more strongly interacting dark matter particles in a disk shape overlapping with the milky way disk.

More on that here: [https://www.quantamagazine.org/20160412-debate- intensifies-o...](https://www.quantamagazine.org/20160412-debate-intensifies- over-dark-disk-theory/)

</comment><comment><USER17> Another promising theory is that dark matter isn't even necessary, we only assume its present due to its gravitation effect, and that can be explained by other phenomenon.

Gravity decreases in proportion to distance squared between objects, but its not observed beyond a certain distance. To compensate, that space was assumed to be filled with dark matter. This theory suggests that gravity switches from a inverse-square law to a different set of rules after a certain distance.

[https://www.quantamagazine.org/20161129-verlinde-gravity- dar...](https://www.quantamagazine.org/20161129-verlinde-gravity-dark-matter/)

<comment><USER18> > Gravity decreases in proportion to distance squared between objects, but its > not observed beyond a certain distance.

This isn't true. F = GMmr^-2 has infinite range. This is true from a theoretical standpoint, and it's also borne out in observations. The Andromeda Galaxy, presently 2.5 million light-years away, is being pulled toward our galaxy and will eventually collide with it. Observations on an even larger scale support the idea that the equation has infinite range.

The above theoretical construct could in principle be contradicted by observations, and if it were, someone would win a Nobel Prize, so there's every incentive to find persuasive evidence that contradicts it.

<comment><USER19> _The Andromeda Galaxy, presently 2.5 million light-years away, is being pulled toward our galaxy and will eventually collide with it._

To support an inverse square law, we'd need to know the mass of our galaxy, and the mass of the Andromeda galaxy. We have the speed, computed from various blueshift methods. We'd also need to know the rate at which the speed changes.

Do we know any of those three? The mass of the Andromeda galaxy is very different if you assume its filled with dark matter, vs. only has visible matter. Which mass is used to confirm the inverse square law? If it includes dark matter, you have circular reasoning: dark matter is hypothesized to make the inverse square law work within the Andromeda galaxy. If it doesn't include dark matter, then why does the dark matter in the Andromeda galaxy contribute to its rotational motion, but not the attraction to the Milky Way?

<comment><USER18> My reply was only in response to this comment --

> Gravity decreases in proportion to distance squared between objects, _but > its not observed beyond a certain distance._

\-- not to the question of what detailed properties gravitation possesses.

<comment><USER19> Ah. I took the comment to say the inverse square isn't observed beyond a certain distance, not that gravity wasn't observed at all beyond a certain distance.

</comment></comment></comment></comment></comment><comment><USER20> sort of OT of the post, but on topic of all the cool discussions about physics we've had here, I want to share one my favorite channels on youtube[1]. Eugene Khutoryansky has put together an amazing collection of very intuitive explanations of all kinds of physics, including cosmology. I also recommend his series on math and electromagnetics.

[1] [https://www.youtube.com/user/EugeneKhutoryansky](https://www.youtube.com/user/EugeneKhutoryansky)

</comment><comment><USER21> Dark matter as particles, rather than some undiscovered gravitational effect at galactic scale, seems like a difficult case to make. If it is particles, the distribution of dark matter in a galaxy has to be highly dependent on the distribution of ordinary matter, or vica versa, and yet there is no interaction. I'd bet on gravity waves and/or quantum mechanical gravity effects leading to an explanation, rather than the discovery of a new class of matter.

<comment><USER9> > _If it is particles, the distribution of dark matter in a galaxy has to be > highly dependent on the distribution of ordinary matter, or vica versa, and > yet there is no interaction._

Incorrect. The distributions do appear to be interdependent, in exactly the way you'd expect if the two kinds of "matter" interacted only gravitationally.

<comment><USER21> Yes, that's true. But are there arrangements of dark matter that are not holding visible matter galaxies together? Does dark matter appear anywhere else?

<comment><USER9> How would we know? The only thing it would do is create some extra gravity where there is no visible source of it.

You could infer its existence from indirect effects, but it would be extremely tricky.

<comment><USER21> Gravity lensing?

<comment><USER11> Yes, that's how we'd infer the presence of an overdensity of dark matter in the absence of visible matter : a background being lensed by an invisible foreground.

There are searches for this which are possible because Einstein rings are well understood, and those appear in particular alignments such that it would be hard to miss the foreground source if it were at all visible. Other lensing structures are subject to tracing error; that is, you lose the ability to distinguish between effects from alignment and effects from the distribution of foreground mass and the distance to the background visible objects.

One major problem is that dark matter overdensities need not be in exact alignments, or produce readily detectable Einstein rings. Moreover, the overdensities must not be that "over" or ordinary matter would have been drawn in, and we could see _that_. (Which would be neat as it would offer evidence on how early galaxies formed in the first place, and narrow out of contention lots of modified gravity proposals.)

There is a debate over the large scale structure of dark matter, with lots of ideas provoked by the X-ray clusters Abell 222 & 223 among others. There may be a "web-like" structure to dark matter where the filaments can be very large compared to the scales of individual galaxies but still quite narrow compared to the less dense spaces between them. These structures appear pretty commonly in simulations grounded in the standard cosmology, although it's not wholly clear why (they may be an artifact of numerical methods, for example).

[http://www.nature.com/nature/journal/v487/n7406/fig_tab/natu...](http://www.nature.com/nature/journal/v487/n7406/fig_tab/nature11224_F1.html)

There are ground- and space-based observatories in the pipeline that will over the next few years narrow the possibilities for various kinds of large scale structure of extra-galactic/extra-galaxy-cluster dark matter.

However, "it's extremely tricky" is fair for now.

</comment></comment></comment></comment></comment></comment><comment><USER22> Of course we will or rather we will understand what causes the phenomenon which we attribute to dark matter.

I don't really see the failures mentioned in the article as failures. We had an idea about how nature works, tested it and showed that we were wrong. It's just the scientific method at work.

<comment><USER9> Yup. This is how the sausage is made (the scientific sausage). Some do not like it, but others find it fascinating.

</comment></comment><comment><USER23> Two crazy ideas:

1\. Dark matter is the "gravity echo" from the past. Gravity is the structural bending of spacetime by mass. The effect of the bending is supposed to travel at the speed of light. What if the effect has been delayed and is added to the present effect?

2\. When a mass is moving through spacetime, the bending of spacetime is asymmetric in the leading and trailing directions, where the leading direction forms a leading crust and trailing forms a flatter tail, just like the blue- shift and red-shift effects on light. The leading gravity wave crust adds to the strength of the gravity.

</comment><comment><USER24> Personally I think that "dark matter" is not matter at all, but ripples that form valleys and hills in the space-time membrane like a plastic bag that has been stretched (by the big bang) and crumpled slightly back.

But I am not a physicist so it is purely speculation from my part and I have no math to back it up. It's just the way I picture it in my head :)

</comment><comment><USER25> The Big Fudge Factor In The Sky Without Which We Look Silly.

</comment><comment><USER26> We will if it isn't.

</comment><comment><USER27> edit: got reemed for even attempting, read below

<comment><USER28> Your theory seems to be based on pop-science understanding of concepts like entanglement. A physicist listening to you would just smile and nod their head. There is no need for particles to pass through a single point for entanglement to be a thing. Both the standard model and quantum theory tell us that such an event isn't possible. And as far as I understand, you don't have matter until 10^-12s, well after cosmic inflation.

Quantum entanglement is not a force, does not cause particles to do things, and cannot be used to build a quantum internet. It merely refers to the fact that although quantum states cannot be known till measured, even distantly separated particles will satisfy quantum relations (opposite spin for two particles, etc). They satisfy them in such a way that they either somehow communicated, knew all along, or other possible strange options discussed in multiverse theory. Bell's inequalities prove that they did not know all along.

Dark matter can't be ordinary matter in a second universe because it doesn't interact with itself. It'd have to be dark matter in another universe. Which would be indistinguishable from dark matter in this universe.

Nothing in physics seeks to do anything. The idea that matter would get together and plan to form black holes so that it can transition into some other state is just silly.

You are trying to solve problems that don't exist, with physics that don't exist. Please, read up on:

[https://en.wikipedia.org/wiki/Pauli_exclusion_principle](https://en.wikipedia.org/wiki/Pauli_exclusion_principle) [https://en.wikipedia.org/wiki/Uncertainty_principle](https://en.wikipedia.org/wiki/Uncertainty_principle) [https://en.wikipedia.org/wiki/Chronology_of_the_universe](https://en.wikipedia.org/wiki/Chronology_of_the_universe) [https://en.wikipedia.org/wiki/Quantum_entanglement](https://en.wikipedia.org/wiki/Quantum_entanglement) [https://en.wikipedia.org/wiki/Bell's_theorem](https://en.wikipedia.org/wiki/Bell's_theorem) [https://en.wikipedia.org/wiki/Dark_matter](https://en.wikipedia.org/wiki/Dark_matter)

<comment><USER27> I've taken the criticism received and edited my comment, but after reading your comment again I think you are being overly critical.

"There is no need for particles to pass through a single point for entanglement to be a thing."

I never said there was, merely proposed it as a possibility.

"Quantum entanglement is not a force, does not cause particles to do things, and cannot be used to build a quantum internet."

Not with classical bits, but theoretically building a quantum internet is possible if we ever figure out how to transmit data via qubits. (as per articles linked)

"Dark matter can't be ordinary matter in a second universe because it doesn't interact with itself."

I don't follow your reasoning here, is there a law that more precisely backs up this statement?

"You are trying to solve problems that don't exist"

On the contrary, I am just using my imagination to attempt to grasp a possible version of grand unified theory, which as far as I know is still something we are trying to work on.

"with physics that don't exist."

How do you know that if you don't know the answer to what dark matter is in the first place? Science isn't just about what we already know, it's about creating falsifiable and testable hypothesis outside the current knowledge-set to expand the currently accepted knowledge set. To criticise hypothesis on content and methodology is valid, but to criticise it simply because it doesn't conform to the current knowledge set is short sighted imho.

<comment><USER9> > _I am just using my imagination to attempt to grasp a possible version of > grand unified theory, which as far as I know is still something we are > trying to work on._

You're attempting to write a super-duper machine learning giant app without having bothered previously to even learn how to code. Start by learning how to turn on the computer first, and go from there.

It's easy to kick back and dream about grand theories. It's also easy to forget the steep road of learning that would allow you to even approach that realm.

</comment></comment></comment></comment><comment><USER29> There is no evidence that dark matter even exists other than the fact that our universe is not expanding at the rate we think it should, based on our current theory of gravity and how much mass we can account for based on the radiation _currently_ reaching us (light). I think it's far more likely that our theory is incomplete rather than some whole new class of invisible matter/energy being conjured into existence just to counter-balance our 1) wrong equations and/or 2) wrong observations. So many non-scientists think dark matter is proven. It isn't. It's nothing but pure conjecture.

<comment><USER30> > _There is no evidence that dark matter even exists other than..._

 _Most_ of our theories about the universe are based on evidence from secondary, tertiary, etc effects. It's often the best we can do.

I don't think you'd find anyone who would object to the idea that "our theory is incomplete" ("all models are wrong", etc), so it seems like your main objection seems to be that we've given a name to a family of theories that attempt to explain the phenomenon we've grouped under "dark matter".

> _I think it 's far more likely that our theory is incomplete rather than > some whole new class of invisible matter/energy being conjured into > existence just to counter-balance our 1) wrong equations and/or 2) wrong > observations_

It's rather human to make an estimate of likelihood based on how long ago something was conjectured to exist :) Moreover "wrong equations" and/or "wrong observations" are part of the very theories attempting to explain our current state of knowledge.

> _So many non-scientists think dark matter is proven. It isn 't. It's nothing > but pure conjecture._

Actually, usually the issue with these discussions are with scientifically literate folks who read a Scientific American article on dark matter in 1998 and have engaged with that as a strawman ever since. Somewhat tongue-in-cheek, but it is odd to me how many people are convinced they're bringing light to the darkness with these kinds of comments.

</comment></comment><comment><USER31> A bit off-topic, but not totally: I am so sick of nautil.us spamming my back button into oblivion that I won't click a nautil.us link never more, until they fix that and someone here say it is fixed.

<comment><USER32> I normally just open things in a new tab, avoids that problem entirely.

But just for you, I clicked the link normally, waited for it to load, hit back, and ended right back up at the HN page. So either an adblocker fixes the problem, or they have.

<comment><USER33> They seem to be adding history items when you scroll. Try scrolling down the page some, then going back. It took me about ten clicks to get back when I tried it.

<comment><USER32> You seem to be correct.

Though the new tab approach still works.

<comment><USER33> Yeah, opening in a new tab can prevent all sorts of idiocy.

</comment></comment></comment></comment></comment><comment><USER29> So much of what you said is hilariously wrong. Probably the most acute example is your claim "Standard Model is mute on gravity". Are you kidding me? Page one of any book of the Standard Model discusses the 4 fundamental forces. Guess what one of them is: GRAVITY.

<comment><USER34> You conducted yourself so nastily in this thread that we've banned this account. This sort of flamewar is exactly what we're hoping to avoid on this site.

We detached this subthread from [https://news.ycombinator.com/item?id=13606710](https://news.ycombinator.com/item?id=13606710) and marked it off-topic.

</comment></comment><comment><USER18> I wish nautil.us would fix their broken page design so it doesn't fill one's browser history with duplicate links and keep one from leaving the site. This isn't a design choice, it's parasitic.

</comment><comment><USER35> We know what it is. It is a socially constructed abstract concept, like "god" or "afterlife" or "pure substances" of Spinoza.

BTW, the "substance propositions" Spinoza has been developed are perfectly sound, except one small flaw - no such phenomena as pure substance ever existed. Dark Matter and related crap is of exactly the same nature - <USER2> more sophisticated phantoms of the mind supported by a sect of believers.

<comment><USER6> I've downvoted your comment because your tone isn't constructive and you're making a rather illogical jump to the philosophical arguments of Spinoza in comparison to questions around modern measurable/observable phenomena in science.

If you'd like to make a less hostile post with a clearer justification of your reasoning I'd be more than happy to debate the subject with you.

<comment><USER35> I do not have anything to add. As a student of philosophy I have seen way to many socially constructed chimeras and memes to not notice modern ones.

The only criteria for establishing a scientific truth is still a replicable experiment which proves an _implementation_ according to some established law. Any simulation does not account for such kind of experiment, being mere a "cartoon" made according to some abstract model. The difference between experiment and simulation is of the same kind as between a cartoon and actual reality.

<comment><USER6> > " As a student of philosophy I have seen way to many socially constructed > chimeras and memes to not notice modern ones."

There's a willful ignorance in this sentence that belies your youth and intelligence. I suspect you don't have an adequate background to understand the observational evidence for our expectation of dark matter (I barely do to be quite honest). I don't think you can fairly dismiss offhand the conclusions drawn by hundreds of expert physicists based on your experience.

I've known more than one physicist that were also well-studied students of philosophy. If you have reached a brilliant and well-justified conclusion that they failed to see you should clearly write it to justify your case.

>"The only criteria for establishing a scientific truth is still a replicable experiment which proves an implementation according to some established law. Any simulation does not account for such kind of experiment, being mere a "cartoon" made according to some abstract model. The difference between experiment and simulation is of the same kind as between a cartoon and actual reality."

Science (and philosophy for that matter) are defined from consistency of observation. I fail to see your point about an experiment measuring a "cartoon" when that is the reality in which we intrinsically exist and for which prediction will provide the most value.

<comment><USER35> Try this. This is a particularly good one. Science is definitely not a consensus of observations. It is a systematic effort to unveil what is.

[http://oyc.yale.edu/ecology-and-evolutionary- biology/eeb-122...](http://oyc.yale.edu/ecology-and-evolutionary- biology/eeb-122/lecture-23)

<comment><USER6> I'm not asking you to send me a resource that has led you to your current conclusions.

I'm asking that you formulate an argument that I can read that will make me believe that your arguments are well-formulated here. You made a very strong statement and I think that if you could logically justify it in written form it would be a valuable contribution to the thread.

<comment><USER35> I could only try to clarify the same principles a bit more. Non-falsifiable and non empirically verified hypothesis does not amount for a science and constitutes a set of beliefs similar to religion among a community of its followers. As long as there is absolutely no way to reliably test or even measure, leave alone empirically validate anything, this set of beliefs is technically is a non-science and should be explicitly named as mere speculation.

My first comment was the claim that what we deal with is a socially constructed phenomena, similar to a religious belief or a mass-hysteria because it is a) cannot be tested and b) constructed by a certain social group. Technically, I do not see any contradiction in my claim.</comment></comment></comment></comment></comment></comment></comment>