Psychological techniques to practice Stoicism - <AUTHOR> https://hoanhan101.github.io/2020/04/26/guide-to-the-good-life <comment> r-bryan I can recommend _The Happiness Hypothesis - Finding Modern Truth in Ancient Wisdom_, by Jonathan Haidt, as relevant here.

The book was suggested to me by a CBT practitioner. It languished on my shelf for several years because it sat adjacent to a bit of new age fluff, and I thought the subtitle sounded like it was another bunch of lost-wisdom-of-the- ancients drivel. I thought wrong: one should not judge a book by its cover.

The book is serious -- Haidt is a social psychologist at NYU Stern School -- yet eminently readable. It pulls in relevant aspects of the "ancient wisdom," evaluates them in the context of contemporary research, and shows where they can help us today and where they are outright plain wrong.

I can't say it has changed my life yet, but it has helped settle the inchoate bits that I have taken from the Enchiridon, Meditations, etc., into a useful way of thinking about the world and my place in it.

Now on to William Braxton Irvine...

<comment><USER2> Ah, Jonathan Haidt haven't heard of him in a long while. I second this. If you like stuff like this, then you also might like:

\- Search Inside Yourself by Chade Meng-Tan

\- The Luck Factor by Richard Wiseman

I read the Happiness Hypothesis quite late in my development regarding "how to be come happier?" I already knew a lot of the ideas in there, but it presented its ideas a bit more clearly than whatever I read from Martin Seligman (many books) and Suzanne Segerstrom (Optimism).

This is why I'd still recommend that book.

I also recommend to read the concept on self-learned helplessness (Seligman researched it) if you haven't already.

One book that I actively disrecommend nowadays is Man's Search for Meaning. I didn't look too deep into it, but there's a lot of controversy on the truth of his claims (e.g. some claim he was in the concentration camps for a few days, not months or years like he implicitly depicts).

Disclaimer: it's these types of books that motivated me to do an entire undergraduate degree in psychology back 6 years ago. Only to realize most of it is nonsense. Yet, at the same time, not all of it is nonsense. Plus it gave me the skills to see what was and what wasn't nonsense.

</comment></comment><comment><USER3> The problems with Cynicism, Scepticism, Epicureanism and Stoicism is that they don't really adhear to the notion of 'everything in moderation'. The logical extremes either can lead to some genuinely useless approaches to life.

If one should never worry about things that they cannot possibly control, even if it directly affects one's life, because we are just going to cease to exist at some point anyway, how would one now whether or not they could alter it, if they never began worrying? This very idea lead to several prominent Stoics to commit suicide, because might as well hasten my eventual ceasing of being?

Perhaps if they had concerned themselves with things that on the surface seemed outside of their reach, they might have realised that some things are approachable, even if the solution is not obvious.

The idea that one should avoid worry about things outside one's control is not a bad suggestion in general, it just should not be taken as an extreme. I mean, there is probably a reason why philosophers went back to Aristotle and Plato _after_ those other four Schools saw prominence.

Jewish, Christian and Islamic philosophers weren't trying to make their religions compatible with Zeno's or Epicurus' teachings, but rather Plato's and later Aristotle's.

<comment><USER4> > This very idea lead to several prominent Stoics to commit suicide, because > might as well hasten my eventual ceasing of being?

Reading list above, another aspect is that it has absolutely no answer for when you actually have problems. It starts with assumption that everything is perfect and issues are purely invented out of boredom. That sort of thinking does not help deal with actual stresses nor minimize harm, nothing like that.

Just look at dealing with people part and now imagine dealing with bully, narcisstic or abusive partner. This typical victim response does not make things better, but instead leads to cycle of abuse:

> One of the best way to respond to insult is with humor, especially self- > deprecating jokes. Another way is with no response.

Likewise, I went through periods of self-denial of pleasure. I tended to decide that I wont waste time anymore and cut fun things out of my like. Depression and low productivity followed each time. It turns out that humans need some pleasure in their lives.

<comment><USER5> > It turns out that humans need some pleasure in their lives

Yes, don't cut out pleasure. You might want to borrow a leaf from A.A. Long (the preeminent expert on Stoicism):

 _I was sometimes asked which one of the three schools I fancied for myself. Please don't be shocked at my flippant reply: "I am a stoic (lower case!) in the morning when I write, a Sceptic in the afternoon when I teach, and an Epicurean in the evening when I have fun."_

</comment></comment></comment><comment><USER6> I like Stoicism and have read many books on topic. Stoicism provides me with mental tricks to think more positively and be more resilient. However, there are some presuppositions that underlie the philosophy that must be take on faith. "Lead a virtuous life," for one. But why? What's the difference if I do not live virtuously? As an Atheist I suppose I do look for these answers in part because I have not accepted the answers from religion. Perhaps Stoicism never claimed to provide a deeper meaning to life, and if one goes in without that expectation one will likely be less prone to disappointment.

<comment><USER7> I think couple of things can be observed to support living virtuously without needing to resort to invoking any supernatural cause:

1\. Observe a fundamental law of nature: Whatever we give to the nature is what nature grows and gives us back in many times over. We give seed to earth it gives back us a full fledged plant. We genuinely appreciate people and spread happiness in return we receive the same.

2\. Observe our conscience: Even though you can denounce religion and God but at least we experience and listen to our conscience, inner voice regularly. Not sure how much modern psychology has done research over this stuff but at least in yogic circles it's been extensively covered as a fact that the more you abide by virtues in your thoughts, speech and conduct, the more calmer, peaceful and contented you will be (lesser inner conflict/clear conscience etc.) And that's fundamental to lasting happiness

<comment><USER6> To me #1 sounds like an appeal to nature without basis. It sounds a little like "The Secret"—positive actions have positive reactions—which I haven't seen evidence of sufficiently to make a law of.

I don't know what "listen to our conscience, inner voice regularly" or "abide by virtues in your thoughts" mean.

<comment><USER7> Regarding the conscience, it's blabbering of the mind. while you're busy in some activity you may not notice it, but it's there in your subconscious. To observe it, just sit for few minutes and try to see thoughts originating in mind. This constant chatter, which may include grudges, guilt, complaints, fear, phobia, jealousy, envy , worries etc. are emotions that spring up when we're too focused on ourselves in our life. The virtuous, kind actions that we do for others help in expanding our consciousness; our prospective toward life changes and consequently the self-obsession decreases resulting in greater inner peace, calm and contentment.

</comment></comment></comment></comment><comment><USER8> > Willpower is like muscle power: the more exercise, the stronger they are; > the more will power we have, the more self-control and courage we have.

IIRC: studies have not validated this

<comment><USER9> Yes, a dated analogy:

[https://hbr.org/2016/11/have-we-been-thinking-about- willpowe...](https://hbr.org/2016/11/have-we-been-thinking-about-willpower- the-wrong-way-for-30-years)

<comment><USER10> Ego depletion would kinda be the opposite anyway.

</comment></comment></comment><comment><USER11> > We are unhappy largely because we're insatiable. After working hard for what > we desire, we quickly get bored, dissatisfied, take things for granted and > eventually chase new desire.

This makes me worry about climate change. For people to want to fly less, buy less, eat more sustainably etc. they'll have to become more satiable or change to only wanting things that have a low environmental impact.

</comment><comment><USER12> Can anyone answer if it is really possible to learn, make it natural to be more relaxed, more happy in everyday, without taking medicine?

I think I am more anxious than I really need, and can be more relaxed and happy. For example, I study part-time and constantly feel self-inflicted pressure to study properly, making study feel like burden than fun. Or I worry too much about minor issues like broken pump in the garden, finding a kindergarten for my baby, etc.

In reality, I am doing fine: I have a good income, great wife and son, no major health issues, I already have a degree and my studies of maths are more for self-growth with room for failure.

I understand it logically that I do not want to treat my studies as obligation and can enjoy the process, that I want to be more relaxed and resilient to small problems. But plain understanding does not turn me into a more relaxed personality, as it does not pierce deep enough into the brain. Is there a way to re-wire our brains for better attitude and happiness?

<comment><USER13> I hear meditation helps. Whats helped me is acting as if The Law of Attraction is real.

</comment></comment><comment><USER4> The advice on how to deal with people completely ignores existence of abusers, bullies and narcissists.

If applied to abusive or potentially abusive relationship, it would go right into the abusive cycle. It is opposite of what you need to do to set boundaries and opposite of what you need to do to recognize first issues as they appear.

</comment><comment><USER14> That is a great quick read. All of those points land nicely, with one exception from my perspective:

> We must learn to welcome whatever comes to us and trust that it happens is > for the best.

I think maybe that was reworked and an extra word for left in, or another got left behind in error...

But aside from that, the idea that even bad things were meant to happen for a reason, that somehow later we will come to understand -- that seems to imply a faith in some God or "universe" watching out for us, which seems counter to the general tenets of Stoicism.

We can choose to rationalize bad things happening in a way that tries to find opportunities for growth and learning. But that is different than trusting that it is all "for the best."

<comment><USER15> A suggested rephrasing:

"We must learn to welcome whatever comes to us and trust that we will be able to make the most of it."

<comment><USER16> Thanks, that sounds more reasonable to me.

</comment></comment></comment><comment> a-saleh Just beware you actually practice stoicism, acceptance and the good stuff and not just dissociation ;-)

</comment><comment><USER5> For those who wish to truly deep-dive, I strongly suggest to skip the "meta books" on Stoicism, and go straight to the original works. There's the Big Three—Seneca, Epictetus, and Marcus Aurelius. Be prepared to invest _at least_ ten months (the longer, the better) of _active_ study to get a decent grounding.

From my experience of reading multiple translations of the Big Three, for someone new to Stoicism, I'd suggest _not_ to start with the popular recommendation of Marcus Aurelius.

Start with Seneca's Letters, then Epictetus (an ex-slave, and a profound influence on Marcus Aurelius), and only _then_ Marcus Aurelius, the Roman Emperor. (To quote the foremost Stoic scholar, A.A. Long: "[...] That an ex- slave actually shaped a Roman Emperor's deepest thoughts is one of the most remarkable testimonies to the power and applicability of Epictetus' words.")

The quality of the English translation matters a _lot_. Here are my recommendations:

• Seneca: _Letters on Ethics_ — translation by Margaret Graver and A. A. Long. This is the most recent translation, reads extremely well, outstanding notes, and wonderfully typeset. It's translated by the current foremost experts; can't get better than this. I've been reading this for four months. (If this is a tad pricey for you, I've also heard good things about _Selected Letters_ ; translated by Elaine Fantham.)

• Epictetus: _Encheiridion, and Selections from Discourses_ , by A.A. Long. This is a short book; the value addition here is the great introduction, and the outstanding glossary. (NB: there is no escaping full Discourses of Epictetus—refer below.)

• Epictetus: _Discourses, Fragments and Handbook_ — translation by Robin Hard, intro by Christopher Gill; Oxford University Press. Spend a good four months immersing yourself in it. Epictetus is full of heavy irony, dark humor, histrionic wit, and sarcasm. Absolutely my favourite.

• Epictetus: _A Stoic and Socratic Guide_ , by A.A. Long. _Important Note_ : To get maximum value out of this, you must have already read _at least_ one translation of Epictetus' full Discourses! This book orients the reader to Epictetus with an extremely valuable context: how not to misinterpret his unqualified faith in "divine providence" (which can grate on our "modern ears"); the influence of Plato and the "Socratic Elenchus" (colloquially known as "Socratic Method"); deep insights into Epictetus' own inimitable style; and a rich bibliography.

• Marcus Aurelius: _Meditations_. There are at least six translations. I'd suggest to start with the gentler translation by Gregory Hays. If you like it, then you can research other translations. (A.S.L Farquharson spent a lifetime on his translation of the _Meditations_ ; it also has commentary. I sometimes consult this edition.)

• _The Inner Citadel: The Meditations of Marcus Aurelius_ , by Pierre Hadot. This needs to be read only after you've read _at least_ one translation of Marcus Aurelius This is a fantastic dissection of Aurelius' work—Hadot studied him for 25 years. Besides fresh translations of the Meditations, it also contains unparalleled summary of Epictetus, and many quotes of Seneca.

                 - - -

I'll end with one of my favourite Epictetus quotes:

 _" For sheep, too, don't vomit up their fodder to show the shepherds how much they've eaten, but digest their food inside them, and produce wool and milk on the outside. And so you likewise shouldn't show off your philosophical principles to ordinary people, but rather show them in the actions that result from those principles when they've been properly digested."_

<comment><USER17> Thank you for the list. What made you decide to go on this journey? How have this process changed you?

<comment><USER5> I first heard of Marcus Aurelius more than five years ago when I was reading a book called _" Flow: The Psychology of Optimal Experience"_, by Mihaly Csikszentmihalyi (pronounced as _Me-High Chick-Sent-Me-High_ )—itself a book I highly recommend; he spent his entire career devoted to this topic. That made me wanted explore Stoicism to better understand what they said about human well-being and what the Greeks called _" Eudaimonia"_ (flourishing). Although, I only began the deep-dive some two years ago.

How has it changed me? In many positive and enabling ways. It's an ongoing process, but it certainly made me more resilient, tranquil; ability to give better structure to my attention when in solitude; better ways to deal with setbacks; and to learn to "make correct use of mental impressions" (Epictetus' favorite way of describing the Stoic project), among others.

<comment><USER18> Interesting. I also came across Meditations from M.A. when reading Flow by M.C. I downloaded a license-free ebook of Meditations, but found the translation to be excessively complicated and ended up abandoning it. I really appreciate your recommendations now, and will fore sure give them a try again.

<comment><USER5> Glad to be useful. A poor translation is definitely a deal-breaker. It is absolutely worth investing in good English translations (taking time to do some research helps). Most of the good translations have a robust introduction that situates the topic in context with helpful notes, references, and bibliography.

Good luck!

PS: I maintain that good old physical copies are superior to e-books for these kinds of studies. Especially when you need to frequently refer to the notes—it makes flipping back-n-forth far more pleasant. Also spatial aspect of a paper- based book, better retention, and other well-known benefits.

</comment></comment></comment></comment></comment><comment><USER19> A few of my fav:

      A guide to the Good Life by William Irvine

      The Daily Stoic by Ryan Holiday

      The Art of Living by Epictetus

      Meditation by Marcus Aurelius

Although not directly related to Stoicism, there are Stoic lessons in them:

      Man's Search for Meaning by Viktor Frankl

      The Power of Now by Eckhart Tolle

      The Fifth Agreement by don Miguel Ruiz

      Stumbling on Happiness by Daniel Gilbert

</comment><comment><USER4> Reading it, I was like "nah, the reasons for my unhappiness were completely different" but then came this:

> Most of us are already living the dream, having a wonderful partner, a dream > job, a good car though we take things for granted other than delighting in > them

I mean, yeah, this is psychological technique only for people who have it all.

</comment><comment><USER20> _> A person's virtue depends on their excellence as a human being, how well one performs the function for which humans were designed._

humans weren't designed, they were selected for through a happenstantial process. random mutation is critical to this process, and so any one of us can be deeply at odds with whatever the majority are geared towards.

<comment><USER21> > "humans weren't designed, they were selected for..."

unless i'm mistaking your intent, "evolved" might be the better phrasing if you're objecting to the agency implied by "designed", as "selected for" also implies similar (super-)agency.

<comment><USER20> you're right that "selected for" also implies agency. if i wrote my comment a second time i'd replace that with "came about through".

my main intention though is to point out that being the product of an evolutionary process we can't find definitive purpose in our origins.

</comment></comment></comment><comment><USER22> Thanks for that, it's a quick and rewarding read.

</comment><comment><USER16> Can someone recommend an audio book on this ?

</comment><comment><USER23> >[https://hoanhan101.github.io/about](https://hoanhan101.github.io/about)

I want psychologists to write a solid book on this subject.

So far majority of posts that I have read on this subject have been by software developers, which strikes me bizarre. You can leave your Zen and Art of Motorcycle Maintenance out of this.

Software developers are not qualified to write about this. They are clueless dingbats and don't know it.

How about some proper sources on the subject?

<comment><USER24> > Zen and Art of Motorcycle Maintenance

?? OP doesn't mention this at all. Also, it's a great book--read it!

<comment><USER25> When I was a teenager, I bought my first motorcycle and this book.

I was thinking that this book would contain a tech manual for repairing motorcycles in a special "zen-way".

I was very angry when I finished reading it.

<comment><USER24> Ha ha. Sorry that happened to you.

The intro does say: _It should in no way be associated with that great body of factual information relating to orthodox Zen Buddhist practice. It 's not very factual on motorcycles, either._

On the other hand, I hope you enjoyed your motorcycle.

Have you looked at the book again? One surprising thing for me is that as I've reread it over the years, it seems different each time.</comment></comment></comment></comment>


Ask HN: As a developer, how can I get better at design and UX? - <AUTHOR> Hello,
I'm the sole developer of a SaaS product. Long story short, I'm great at backend and frontend development when it comes to functionality, and getting things done.
However, when it comes to creating a "nice looking" site/app that looks and feels good, I suck. I'd like to get better. Any strategies to get better besides "Keep trying and learning from your mistakes"? <comment><USER2> Some ideas: try finding a way to work in proximity to people who already have those skills and see what you can pick up by osmosis - either by just sharing a physical space or by hiring somebody for a while and working closely with them.

Alternatively, spend some time focusing really closely on examples of work you like, especially compared with some you don't, and think about why one works better than the other. Imagine how small changes would impact the good design.

Finally, I think restraint is key in this situation. "First, do no harm" is a much better angle than trying to create a masterpiece.

The most efficient approach will still be partnering with somebody who's already good at this, though.</comment>


Ask HN: How can I video chat using my TV - <AUTHOR> I want to what people's setups are today to video chat with family and friends using their tv - FaceTime, WhatsApp etc service dosnt matter.<p>It seems like one needs to buy a Mac mini or similar computer and hook it up to the tv  to do this. Wondering if there is a better way <comment><USER2> The only special-purpose device I know of for what you want is Portal TV from Facebook.

Most video chat isn't done via television.</comment>


Stupid Shit No One Needs and Terrible Ideas Hackathon - <AUTHOR> http://stupidhackathon.github.io/ <comment><USER2> This could be really fun. Some quick ideas:

Like React.js But For Cooks - Metered digital MSG dispenser (perhaps in a spray?)

Monetizing The Eschaton - Credit card-reading donation plate / tip jar

Hyperlocal Paranoia - Device with LED/beeper + wifi, indicates whenever a new/unseen MAC address is nearby

Flesh Skeuomorphism - Computer mouse with skin-like texture

Scatological APIs - Device and service which monitor stool movements. Summaries, graphs, alerts.

Targeting The "Hikikomori" Space - Take any/all existing services (Uber, WashIO, food delivery, etc) and guarantee no conversation required.

<comment><USER3> _Scatological APIs - Device and service which monitor stool movements. Summaries, graphs, alerts._

A truly shitty big data movement...

Though of course it's actually a pretty good idea. See [1] for example.

[1] [http://quantifiedtoilets.com/](http://quantifiedtoilets.com/)

<comment><USER4> Adult Swim did a skit on this.

[https://www.youtube.com/watch?v=DJklHwoYgBQ](https://www.youtube.com/watch?v=DJklHwoYgBQ)

<comment><USER5> _Stares right into camera_ Actively Harass your congressmans staff

</comment></comment></comment></comment><comment><USER6> The Stealing Economy. Stealing does need to be disrupted. For too long "Big Pawn" has given thieves pennies on the dollar for hot goods.

<comment><USER7> > _Stealing does need to be disrupted. For too long "Big Pawn" has given > thieves pennies on the dollar for hot goods_

I disagree. Current pawnshop technology is lagging behind nearly every field. Why should I have to shlep my legitimately acquired car stereo, or the television without any cables or remote control down to a physical location?

I should be able to log onto paw.nr, snap a photo of the thing I want to pawn with my iPhone 4 that has "Kimberly & John Forever" engraved on the back, and instantly get bitcoins deposited into my wallet.

If I don't pay that money back in time, Pawnr locates a willing buyer, they use Taskrabbit or Fiverr to send someone to my house to collect the merchandise and deliver it to the buyer.

Disruptive as fuck, bro.

</comment></comment><comment><USER8> I love that Peter Thiel is a category

<comment><USER9> "Delighting The Designer" is my favourite I think

<comment><USER10> "Don't you just love Comic Sans!?"

"Maybe we should present an alert() to the user here"

</comment></comment></comment><comment><USER11> They were inspired by [http://www.stupidhackathon.com/](http://www.stupidhackathon.com/) If you can't wait for the results, have a look at that one.

<comment><USER12> Just to note: that site gets very NSFW the further you scroll down.

Also, it is sad that _teledildonics_ is not making a return this year. The best-named category by far, and probably a real thing somewhere in the adult industry.

Presumably, professionals working within this field may then refer to their occupation or specialization as that of a _teledildonicist_.

<comment><USER13> While it's not in the hackathon (I have /so/ thought about entering though), teledildonics is very much a real thing and there are more products out right now for it than ever. Hell, there's even a pretty big patent war happening that I'm working on writing up.

And teledildonticist has been in my twitter bio for years, yes (I run the metafetish blog listed in the other comment). :)

<comment><USER12> This is why I love HN. You make a post, and often receive a reply from a domain expert. Teledildonics isn't even an exception.

Thanks, you made my day. :)

</comment></comment></comment></comment><comment><USER14> Dammit, I am going to be working Los Angeles when this goes on. Wishing the event great success, I was enormously impressed by previous ones and think these hackathons serve an incredibly important social function.

</comment><comment><USER15> I like subtle dig at Vessyl [https://www.myvessyl.com/](https://www.myvessyl.com/)

</comment><comment><USER16> Previously, at UWaterloo...

[http://terriblehack.website](http://terriblehack.website)

</comment><comment><USER17> Haha, I love the Google Glass rollover image used here.

</comment><comment><USER18> edibleX is the most exciting category imho. I've always wanted to eat my computer after hitting a milestone.

</comment><comment><USER19> maybe I am a bit odd, but a a lot of these seem really viable.

Servitude-As-A-Service seems particularly viable. We are in an economic state where indentured servitude sounds like a decent deal.

</comment><comment><USER20> Registering. Thanks

</comment><comment><USER21> Smart Watches

</comment><comment><USER22> Is this not the gratuitous negativity that Hacker News seeks to avoid? Satire is not universally good. Many start-ups in their infancy could be classified using that list. Indeed many of those start-up's founders come here for resources or support.

<comment><USER23> Social critique isn't the same as "gratuitous negativity". I got a lot out of reading the projects that came out of last year's hackathon.

<comment><USER22> How can 'Stupid Shit No One Needs' be classified as a social critique by any respectable semantician?

<comment><USER3> Because it makes people smile?

Also because they are actually going to _make_ it?

Emoji is stupid shit no one needs. It also makes people smile.

<comment><USER22> Do you really need to criticise the actions of others as 'stupid' to make yourself smile?

<comment><USER24> Is your dogged persistence in this thread simply a test of our collective ability to abide by the new policy?</comment></comment></comment></comment></comment></comment>


Markets are efficient if and only if P = NP (2010) - <AUTHOR> https://arxiv.org/abs/1002.2284 <comment><USER2> While this is a fun, the title is a little strong.

There are three limitations (whuch apply to many papers about P=NP).

1\. The market could still be efficient, because the situations which must arise to cause P vs NP problems are very complicated. In particular thry require very expensive indivisible things to buy, whereas in most situations we can treat things like shares as continuous with only a small error.

2\. Markets could be efficient if P=NP and we know how to solve NP probkems in P, and we do it. The title makes it sound like the market will already be efficient if P=NP, which isnt true.

3\. Even if P=NP, the polynomial could still be big enough the market cant be efficient. Similarly, P could not equal NP but the expoenential be small enough markets can still be efficient in reality.

<comment><USER3> On two, as this appears to be a cross disciplinary paper, it's important to consider that some economists currently claim markets are efficient (the efficient market hypothesis, which is like a big open question in economics). By drawing a link between the EMH and P=NP (which many computer scientists believe is unlikely) the author is linking two open questions with opposing beliefs. So I think point two is sort of a technicality that with context it should be understood that the author is specifically talking about two open questions as they stand today.

Also to further hammer home the point, due to the phrasing of the EMH, although no one may currently be using P=NP, markets would still have the efficiency property _now_ even if no one is exploiting it. Perhaps this sort of vacuously true statement rubs you the wrong way (like it does me a bit) with the strength of the "if and only if" the author used. But if you read "markets are efficient" as the EMH then it is still a valid literal formulation.

On three, sure that's great for reality. But for the formulation of markets being efficient as an inherent property (again the EMH) of markets, the size of the market could be held as effectively infinite (or at least extremely large) and the property should still hold. At some point the size of the theoretical market will explode the polynomial, and for the EMH to hold P=NP must be true.

<comment><USER4> I don't think economists claim markets are efficient. There's far too many examples to the contrary - see amazon, wellsfargo, and Verizon as examples. While those companies do technically have competition, they operate with significant market power.

Also, I once heard an Econ explain EH as "true if enough people operate under the assumption that it is not true"

Edit-After waking up a little more, I'm not entirely sure of my statement that amazon, wellsfargo, and Verizon serve as examples against EH. But the later quote I heard from someone with 30+ years of research.

<comment><USER5> The efficient market theory is that all information, public and private, is incorporated into all stock prices at all times, so there's no point to researching companies to try to outperform the stock market. I don't think anyone believes it is literally true, just that it is a good model for most stocks most of the time. If everyone believed it then no one would bother to research stocks, and the markets would be less efficient.

<comment><USER6> That's a far more limited claim. There's a very common claim that "markets are efficient". Extending to all markets all the time. Explaining why market based solutions are the best way to provide health care and education and other (arguably common) goods.

But many markets (the labor market, the health care market, etc) work in such a way that it's ridiculous to assume that most participants know all public and private information all or most of the time.

<comment><USER7> The EMH is specific to asset markets. So stocks and bonds basically. No (respectable, well-known) economist has ever argued that all markets are always efficient.

Also what people mean when they say markets are efficient in other contexts means something very different. The EMH specifically describes how quickly and what kinds of information get incorporated into asset prices. It doesn't make claims about how markets organize production or optimize utility without centralized direction, which is usually what people mean when they say free markets are efficient.

I think a lot of confusion has arisen from the very general-sounding name of the hypothesis which does not reflect its relatively narrow claims. Not that I buy the EMH (no pun intended), but that's a different story.

</comment></comment></comment></comment></comment></comment><comment><USER8> Most people seem to read this as a proof that markets are inherently flawed and as lending support to their ideological distrust of market economies. I think that if the authors thesis holds true and p indeed != np, this kind of conclusion could spell an even bigger problem for those who advocate to agument or replace market economies with another, typically more centralized, form of economic calculation. Allende's cybersyn famously used linear programming (P) in order to centrally 'simulate' and improve upon more regular market mechanics. If the authors thesis holds I think it's actually an argument in favor of the economic calculation problem talking point of Hayek and the like: efficient calculation of economic distribution problems is impossible and flawed dynamics of the market are probably close to the best approximation we can afford.

<comment><USER9> When I tried to read about Allende's cybersyn all I could find are a few retro-futuristic furniture, but no meat whatsoever about the kind of software that was behind. It looked like pure PR to me. Do you have good sources about it? It has always intrigued me.

Personally I think it is very unlikely that the markets are close to the best approximation we can afford. The current market-making agents use limited intelligence on limited data. It is an efficient system in the sense that it beats randomness and it beats a central (human) intelligence with (allegedly) superior access to information.

<comment><USER10> I'm interested in this. So far, the best resources I found are:

\- "Red Plenty" by Francis Spufford, a mix of fiction and non-fiction about planning experience in the USSR. It includes a rich bibliography and references to papers published over the past 70 years around this issue.

\- There are few papers by Chinese economists, most notably this one: [https://boingboing.net/2017/09/14/platform- socialism.html](https://boingboing.net/2017/09/14/platform-socialism.html) (you have to mess around with Sci-Hub mirrors to get a free copy).

\- There are few papers and books by Michael Ellman, e.g.: [https://www.amazon.com/Planning-Problems-USSR- Contribution-M...](https://www.amazon.com/Planning-Problems-USSR-Contribution- Mathematical/dp/0521202493/ref)

\- I also have a few primers on linear programming in my to-do list, e.g.: [https://www.amazon.com/gp/product/0486654915/](https://www.amazon.com/gp/product/0486654915/)

\- Somewhat tangential, but "the greatest American capitalist" ripping into EMH is a fun read too: [https://www8.gsb.columbia.edu/articles/columbia- business/sup...](https://www8.gsb.columbia.edu/articles/columbia- business/superinvestors)

None of these really talk about the software still, but I would imagine a combination of:

\- existing supply-chain systems already in place at Amazon, Walmart, etc.,

\- something along the lines of non-monetary Kickstarter to gauge popularity of ideas from the ground up, and encourage innovation

\- strong democratic institutions

\- still allow free market at low levels, like individual entrepreneurs that don't employ anybody (once you employ someone, it must be a co-op).

Dunno, these are just random ideas in my head. :)

<comment><USER11> Check out "Towards a New Socialism", by the aforementioned Cockshott and Cotrell. Cockshott himself is a computer scientist and proposes planning the economy based on solving a linear system of labour inputs.

<comment><USER10> Ah, yes, forgot to mention them. I haven't read the book yet, but read some of their papers, yes those are good too.

</comment></comment></comment></comment></comment><comment><USER12> I'm amazed that someone has written a paper that considers computational complexity that isn't written in LaTeX...

<comment><USER13> That reminds me of Scott Aaronson's post about the early signs a complexity paper is unlikely to be valid: [https://www.scottaaronson.com/blog/?p=304](https://www.scottaaronson.com/blog/?p=304) Not tex is the first point.

</comment></comment><comment><USER14> Frankly, everybody with a bit of economic common sense knows that efficient market hypothesis (EMH) is just a weird theoretical nonsense which is nowhere close to describing real world.

If you want a full critique, read Steve Keen's Debunking Economics, it has a chapter on EMH.

Oh and by the way, there is quite a bit of people who believe that P=NP. Most famously Donald Knuth. I recently became convinced about that as well.

Amusingly enough, the first thing that a rational person would do upon discovering a relatively efficient algorithm to solve NP problems would be to cash in all the Bitcoins. Thus proving in practice that no, markets are not really efficient. :-)

<comment><USER15> > Frankly, everybody with a bit of economic common sense knows

Citation? True Scotsman fallacy?

<comment><USER14> I gave a citation. When I say "everybody with a bit of economic common sense", I mean everybody in economic profession who is able of some elementary reflection on what they are doing. Even most neoclassicals (which is probably the only school where somebody actually believes in EMH) know that many of the theoretical assumptions are bullshit. Another classic example, aside from EMH, is SMD theorem.

I am pretty sure that most economic Nobel prize winners do not believe in EMH, from the top of my head, Akerlof and Kahneman.

<comment><USER15> You gave a link to a popsci book whose Wikipedia Criticism section is ... unforgiving and relentless.

You then double down on your True Scotsman fallacy, mae a sweeping unsupported claim about a nebulous group of people, and follow it up with another conjecture about another group in an attempt to appeal to authority.

We can do better than this.

<comment><USER14> So do better! Find me an economist who truly believes in EMH and is either not a neoclassical (that's about half of all economists) or makes some real-world economic decisions (like in a central bank) or has expressed his belief in support of EMH after 2008 crash.

I gave you two Nobel prize recipients who actually wrote famous articles explicitly outlining market inefficiencies.

Regarding Steve Keen, I don't have my copy handy, but I am sure it has plenty of additional citations. While it is written in accessible style, it is certainly not unsupported. (I personally think that every student of economics should read him, but it's up to each individual what they want to do with their free time.) Many post-keynesians I have read expressed similar dismay about EMH.

<comment><USER15> The product description for the book you quoted:

> Debunking Economics exposes what many non-economists may have suspected and > a minority of economists have long known: that economic theory is not only > unpalatable, but also plain wrong.

Plainly alludes to the fact that the book is not mainstream economic theory. People arguing for minority views of complex subjects find — rightly — that the burden of proof is on them, and not the other way around.

Related: it's not in the least bit surprising to see the book make an appeal to common sense over "those experts". Truly we live in the age of Trump and Farage.

<comment><USER14> And Sharpe and Fama, which he quotes expressing doubts about empirical validity of EMH, are mainstream?

But you can only lead horse to a water..

<comment><USER16> What's your opinion on Mandelbrot?

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER17> What does this mean for the class of PPAD-complete [1] problems?

Someone correct me if I'm wrong, but if 1\. Nash Equilibrium ⊂ FNP 2\. "Markets are efficient" => FNP ⊂ FP

How is this different from "FP = FNP if and only if P = NP" [2], which is a result already found?

[1] [https://en.wikipedia.org/wiki/PPAD_(complexity)](https://en.wikipedia.org/wiki/PPAD_\(complexity\)) [2] [https://en.wikipedia.org/wiki/FNP_(complexity)](https://en.wikipedia.org/wiki/FNP_\(complexity\))

</comment><comment><USER18> > "But given that there are 3n patterns to test, finding a solution, as > opposed to verifying one, requires O(3^n), i.e. it is exponential in the > size of n. For small n, this is computable, even though it is exponential. > But as n grows, it becomes impossible to check every possible pattern > quickly."

If a strategy is a sequence of BUY-HOLD-SELL decisions, then just because there's O(3^n) strategies doesn't mean you need to evaluate them all. It seems pretty easy (if a strategy is only defined in retrospect) to define a greedy algorithm that finds the optimal strategy. (see page 16.)

The author goes on to compare this to the Knapsack problem (pg 19). The thing that makes the Knapsack question (and NP-complete problems generally) hard is that greedy algorithms don't work (as far as we know), whereas it seems like a greedy algorithm work for the problem the author has laid out.

</comment><comment><USER19> This paper is rubbish. Trading is ultimately a partial information, sequential game with an unknown number of participants whose payoff functions (and utilities) are also unknown. Could the market be closer to being efficient if P=NP? Likely. Does P=NP imply efficiency? Not at all.

<comment><USER20> On top of that, the argument rests on the kind of error you expect to see freshmen making in a discrete math course:

> The basic argument is as follows. For simplicity but without loss of > generality, assume there are n past price changes, each of which is either > UP (1) or DOWN (0). How many possible trading strategies are there? Suppose > we allow a strategy to either be long, short, or neutral to the market. Then > the list of all possible strategies includes the strategy which would have > been always neutral, the ones that would have been always neutral but for > the last day when it would have been either long or short, and so on. In > other words, there are three possibilities for each of the n past price > changes; there are 3n possible strategies.

There are 2^n possible histories of length n. If a strategy maps each history to one of three positions, there are 3^(2^n) strategies that consider n bits of history.

<comment><USER21> Why wouldn't it be 3^n? Edit: wait, it's because bitstring -> strategy is a function, right?

<comment><USER20> Yes. Mapping from 2^n bitstrings to 3 market positions.

<comment><USER21> Thanks.

</comment></comment></comment></comment></comment><comment><USER22> Interesting topic and thought experiment. But this theory is not very fleshed out and not at all convincing (especially the part regarding using an existing efficient market to perform computation for anything other than price of the underlying instrument, i.e. what the computation is intended for). The following quote sums up how the author makes very open ended assumptions:

> So what should the market do? If it is truly efficient, and there exists > some way to execute all of those separate OCO orders in such a way that an > overall profit is guaranteed, including taking into account the larger > transactions costs from executing more orders, then the market, by its > assumed efficiency, ought to be able to find a way to do so. In other words, > the market allows us to compute in polynomial time the solution to an > arbitrary 3-SAT problem.

In reality, most financial markets are pretty efficient but none are perfectly efficient -- if they were perfectly efficient, it would imply not only perfectly efficient trading systems and an inability to get an 'edge' on the market, but also perfectly efficient market systems, which are limited by technology, conventions, and regulations (for example, significant inefficiencies arise in US securities from not being open all the time, with very little liquidity still available in the 'after hours' markets). To achieve even 'pretty good' efficiency requires significant energy, and I'm not sure I understand how the author can imply that the energy used in the past to calculate the current price is equivalent to the energy to verify the current price. As a trader, I can tell you that most market participants do not care to verify past calculations of the current price; they only care about the future price, and will generate an action from the differential between the predicted price and the current price.

<comment> Ar-Curunir > _I 'm not sure I understand the author's implication that the energy used in > the past to calculate the current price is equivalent to the energy to > verify the current price._

That's just what P = NP means: the cost to verify a solution is the same as the cost of finding one.

<comment><USER23> In my opinion P = NP does not mean that. There still might be a big polynomial difference between verifying a solution and finding one.

<comment> Ar-Curunir Of course, the concrete costs can be different; I was talking asymptotically :)

<comment><USER23> Well that's the problem, man.

And asymptotically is not the right word either, because n^3 is _asymptotically_ different from n^2. You probably meant poly-time reducible, whichs is quite different from " _the same_ ".

</comment></comment></comment></comment></comment><comment><USER23> I have always been puzzled by why we as computer scientists give such importance to P vs NP. I always thought that even if P = NP the solutions might still be much harder (but only polynomially) to find than to verify. I always get angry when people say that P = NP would mean that problems would be equally as easy to solve as to verify. So, because of that, P v NP always seemed irrelevant to me.

But in the article, there is an interesting section on that:

> If P = NP, even with a high exponent on the polynomial, that means that > checking strategies from the past becomes only polynomially harder as time > passes and data is aggregated. But so long as the combined computational > power of financial market participants continues to grow exponentially, > either through population growth or technological advances, then there will > always come a time when all past strategies can be quickly backtested by the > then-prevailing amount of computational power. In short, so long as P = NP, > the markets will ultimately be efficient, regardless of how high the > exponent on the polynomial is; the only question is when, and the answer > depends on the available computational power.

So this section, if I understand it correctly, says that problems in P are easy because the computational power in the world grows exponentially and we can assume that they will at least once become feasible to solve.

That's an interesting way of looking at it. Is this really the reason why we consider polynomial problems much easier than NP-hard ones?

<comment><USER24> That's assuming computational resources could grow forever without limit, which of course they can't.

<comment><USER17> To add on: Moore's law is "dying", and that places further pressure on algorithms to get faster.

However, even in an exponential world, I am reminded of a quote:

"exponential algorithms make polynomially slow progress, while polynomial algorithms advance exponentially fast".

</comment></comment></comment><comment><USER25> Before people get too carried away criticising markets, check this quote from the paper.

> The results of this paper should not be interpreted as support for > government intervention into the market; on the contrary, the fact that > market efficiency and computational efficiency are linked suggests that > government should no more intervene in the market or regulate market > participants than it should intervene in computations or regulate computer > algorithms.

<comment><USER3> Sure, but if what the author is saying is true, then it implies that there is nothing special about markets, and a system involving an equal number of humans and computers following some other optimization algorithm could achieve similar results in efficiency.

And if a government sponsored and modified such an algorithm in an attempt to optimize for equality (second only to efficiency of usage), such a system could be an effective socialism. It is at least an interesting avenue to consider if mathematical and computational parallels could be constructed.

<comment><USER26> > then it implies that there is nothing special about markets

How so? It implies simply that markets are not efficient. It does not imply that state control would be more efficient and it does not imply that markets are not the _most_ efficient way of determining the value of a resource.

What it definitely says however, is that a government committee could not, in any way, successfully determine the value of all goods and fix prices based on that determination.

<comment><USER3> > It implies simply that markets are not efficient.

No it implies that efficient market states are an NP complete problem. And that we are likely approximating the optimization of efficiency (of the allocation of resources) using markets. Different approximation algorithms have different properties. Might markets be the best in every possible way, sure, but it's very unlikely given what we know about approximation algorithms. It's like one of the best variants in one way, perhaps that's the best way, _but we should figure that sort of thing out_. And that's what this paper is laying the ground work for.

> What it definitely says however, is that a government committee could not, > in any way, successfully determine the value of all goods and fix prices > based on that determination.

In it's editorializing about markets. Which isn't incorrect. But the larger consequences of efficiency being an NP complete problem means that there are many possible algorithms we could use to solve them if they are given equivalent resources. If those equivalent resources are thousands (or millions) of government panels then we should be able to mathematically prove equivalency. That's my point.

<comment><USER26> > If those equivalent resources are thousands (or millions) of government > panels then we should be able to mathematically prove equivalency.

There is a method of solving an NP complete problem with thousands (or millions) of government panels?

<comment><USER3> There is a method of solving an NP complete problem with millions of companies participating in stock markets?

Your question is not related to my point. And you'd have to at least answer it for markets first before I would bother to try. My point is that it is an interesting area of research, we should answer both questions and their interrelationships.

</comment></comment></comment></comment></comment></comment><comment><USER27> The market cannot be efficient because a large portion of public information is not true.

Even if all the information was true, there is still the problem that humans have very poor reasoning abilities combined with herd mentality which almost always overrides the reasoning part.

To predict the market, you don't need to understand the market, you need to understand people's distorted view of the market.

</comment><comment><USER28> I don't think anybody would claim that even the weak form of the EMH applies in all cases. Like the idea that objects of different weights fall at the same speed it's an approximation that can be very close to true in some cases but can be badly misleading in others. If you've ever listened to economists talk about prediction markets they always seem to bring up the idea that markets with low capitalization have low efficiency.

And even looking at the highly capitalized stock market I know at least one story of a major player that got its start noticing a violation of weak-form efficiency and becoming very rich by fixing the violation.

There's no reason to think that actual markets are now finally efficient and in fact there are some that are publicly know, but which only bring a small return and require decades of investment to fix so nobody is interested in trying.

</comment><comment><USER29> Based on a quick skim, this is not a good paper. Computer scientists writing on economics is great, it's helpful to grow new ideas in the field. Unfortunately they sometimes use economic concepts imprecisely at detriment to their question, methodology, and results.

That's the case here. This paper posits a definition of efficiency, but does not explain why that definition is correct or how it relates to other efficiency measures.

A better proof of arbitrage opportunities in markets is Wah 2016, which identifies actual arbitrage opportunities in actual markets.

Separately, what does "Since P probably does not equal NP" mean as a probabilistic statement?

And what is the correct way to concisely and precisely write: "most people familiar with the P = NP problem believe with varying degrees of confidence that P is not equal to NP, but so far no proof exists."

<comment><USER30> > Separately, what does "Since P probably does not equal NP" mean as a > probabilistic statement?

It actually does have a formal meaning! This is one of the most interesting results (in my opinion) on the P vs NP problem. Given a random oracle R, Pr(P^R != NP^R) = 1. So given a random universe, it is almost certainly true that your version of P != your version of NP. At least that's how my theory prof liked to explain it.

Here's a link with the proof: [http://theory.stanford.edu/~trevisan/cs254-14/lecture04.pdf](http://theory.stanford.edu/~trevisan/cs254-14/lecture04.pdf)

</comment></comment><comment><USER31> As I understand it, his argument is that there might be information available that needs time to interpret. And that the time the market took to interpret the available data is not sufficient to gain the maximum insight possible. So that somebody with more computing power then the market could beat the market.

I don't see that as an argument against the EMH. I think it is inherent in the EMH that the market has more computing power then any individual.

I would say that it is the core of the EMH. That more people make better predictions. Because they have more computing power.

I always found it strange that the EMH is often defined as the market price including all available data. As if the data can simply be added without interpretation.

</comment><comment><USER32> So just to better understand the issue of P=NP, am I right in assuming that an NP problem is like trying to build a neural net for image recognition?

In the sense that it takes a huge amount of time and images to train the thing to become smart (in other words, to go through the entire network of neurons one by one and assign better weight values etc) but when it comes to actually verifying if our network is smart all it takes is to run an image straight through the network?

And the issue of trying to prove N=NP is essentially trying to prove that there isn't a magical way to train a neural network with just one image of training data?

<comment><USER33> No, I don't think building a neural net for image recognition qualifies.

NP problems are essentially problems where the following two properties hold:

1\. No better algorithm is known than using brute force -- generating every possible result and checking if it's a valid result.

2\. Checking that the given result is valid is doable in polynomial time or better. (This is less critical to understanding, but essentially your `isValidSolution(input, solution)` function needs to take `O(n)`, `O(n^2)`, `O(n^3)`, (etc.) time or better.)

Essentially, a NP problem is a problem where you have to brute force the solution, but it's easy to know when you've found the correct solution.

If P = NP that means that there are no problems where this is true -- it would mean that any problem where it's easy to know if you've found the solution also has an algorithm for finding it more efficiently than brute force.

Your neural network example doesn't apply because training a neural network doesn't require brute forcing the solution space of the neural network weights. That would be crazy. So it's a problem in P.

<comment><USER32> but trying to devise a program that can predict somebody's password without using brute force is a NP problem? Since its hard to discover what the password is, but trivial to check if it lets you in the vault?

I get the reasoning why people aren't sure if P = NP.

Here is another question.

What defines time? And what about a solution?

Consider the fact that in the theory of general relativity we have the twin paradox.

What if I sent a computer on a rocket at close to the speed of light and then on earth I had the same machine running the calculation that takes a million years, and then when the other computer gets back from it's interstellar vacation, I just have the computer ask the other what it's part of the solution is.

According to the computer that flew away the amount of time that it takes to solve the problem can be considered ~P in a way.

My intuition is telling me that this is probably the wrong way to think about time complexity though.

<comment><USER34> Time and solution are usually abstract concepts here.

The time a turing machine takes to solve the problem can be considered local and in absense of general relativity, it doesn't matter much.

When you talk about time in NP/P, you usually talk about the O Notation (Big O and friends) which gives you the driving factor of the time needed to solve.

Ie, O(n) = 2 + 3x + 9x^2 + 9^x is n^x complexity because this part of the equation will grow much quicker than the others. In reality of course, it can take a while for the biggest part to overtake which is why searching an array linearly in CPU cache can be faster than a hashmap.

The solution in NP/P is usually reduced to either a predicate being proven true or the answer being boolean or can be reduced to either. (ie, solving a jig-saw puzzle can be reduced to "is this jig-saw puzzle solvable" which can be proven by presenting a solution)

The problem you present is not in the scope of NP/P. You're already involving multiple computers and generally here, people still assume general relativity doesn't exist. Plus NP still holds because one computer simply accessed a blackbox function (oracle) while the other solved it in NP.

Time-complexity isn't the only complexity either, you also have space- complexity.

SC tells you how much memory you need to solve a problem. Or rather, how quickly that memory need will grow. You can trade a lot of NP problems to P problems if you have "NP" space complexity.

SC complexity won't spit out a byte-accurate estimation of memory but it can tell you that O(n) = 100 + 100*x will grow linearly in size (O = x) and O(n) = 100 + x^2 will grow exponentially in memory usage (O = x^2).

</comment></comment></comment></comment><comment><USER35> Reading this comment thread is hilarious to a degree. I think that it really highlights how much noise gets thrown into a discussion when your naming becomes too relatable. Essentially bike shedding of theory discussion. If the Efficient Market Hypothesis has been called the "Fundamental Market Property Hypothesis M = H" or similar I doubt most would have made the comments they made. But because "efficient market" sounds to relatable most feel that they can comment without even knowing what the specifics of the EMH are.

</comment><comment><USER36> Meh. Whatever your opinions on P = NP, the efficient markets hypothesis is unfalsifiable. You can only falsify a joint hypothesis of efficiency plus some model of information flow into a market.

<comment><USER37> Wait a minute, if the paper correctly links a theoretical definition of efficiency to the complexity class and indeed shows that markets can be efficient only iff. P=NP, then any future proof that P!=NP falsifies the thesis that markets are efficient. And most experts agree that if we ever get a proof, then it will be a proof of NP!=P.

Knuth is a notable exception, although he has to my knowledge never really vigorously advocated P=NP but merely suggested the possibility that P=NP and that the algorithms to transform NP problems into P problems could be very, very complex but still in P. Seems unlikely, though.

<comment><USER20> The paper doesn't even manage to prove that finding a significantly profitable technical strategy is in NP.

</comment></comment></comment><comment><USER38> The author's claim only applies to weak form of market efficiency.

The original Fama paper distinguishes between three forms of the EMH: weak, semi strong and strong.

The weak form only alleges that historical price info is fully incorporated in the current price. You can still make money by working hard and figuring things out from outside the price history.

The weak form applies to purely technical trading that extracts value from price history like momentum and the simple moving averages cross over studies you see.

</comment><comment><USER39> [https://en.wikipedia.org/wiki/Information_asymmetry](https://en.wikipedia.org/wiki/Information_asymmetry) is still rampant e.g [https://www.economist.com/books-and-arts/2018/06/02/the- rise...](https://www.economist.com/books-and-arts/2018/06/02/the-rise-and- fall-of-elizabeth-holmes-silicon-valleys-startup-queen)

</comment><comment><USER40> Interesting. It is well known in the high-frequency literature that at frequencies higher than 5-minute one obtains market microstructure noise. The observations you observe do not fully reflect the "true" price. I.e. you observe bid/ask quotes with a spread and the "true" price is somewhere in between. This is due to the bid-ask bounce and other latency factors. How can markets ever be efficient if we can not observe the true price of something?

<comment><USER41> There's a transaction cost in either direction.

If you buy a call option, the market-maker buys stock to hedge it. That moves the underlier, and raises the price of the call option he just sold. The reverse is true if you sell a call (or buy a put).

Not only that, but there is a cost for all the people and computers that your order touches as it gets executed.

Without price impact from transactions, markets can't be efficient, because new information has to get priced into the market somehow.

</comment></comment><comment><USER42> P = NP when you nail it.

From the paper: "if markets are weak-form efficient, meaning current prices fully reflect all information available in past prices, then P = NP, meaning every computational problem whose solution can be verified in polynomial time can also be solved in polynomial time. I also prove the converse by showing how we can "program" the market to solve NP-complete problems.

However, there has been no proof that there does not exist some algorithm that can determine satisfiability in polynomial time. If such an algorithm were found, then we would have that P = NP. If a proof is discovered that no such algorithm exists, then we would have that P ≠ NP. Just as most people in the field of finance believe markets are at least weak-form efficient, most computer scientists believe P ≠ NP. Gasarch (2002) reports that of 100 respondents to his poll of various theorists who are "people whose opinions can be taken seriously," the majority thought the ultimate resolution to the question would be that P ≠ NP; only 9 percent thought the ultimate resolution would be that P = NP. The majority of financial academics believe in weak form efficiency and the majority of computer scientists believe that P ≠ NP. The result of this paper is that they cannot both be right: either P = NP and the markets are weakly efficient, or P ≠ NP and the markets are not weakly efficient. "

<comment><USER43> That actually sounds like a refreshingly fun paper to read.

<comment><USER42> Only if you can nerd out about EMH "Efficient Market Hypothesis" for 33 pages

</comment></comment></comment><comment><USER44> What kind of markets get created when the input to the NP problem is 2^10000, I think our idea of markets are based on small scale transactions and extrapolations can't take into account intelligent agents. Also Arrow's theorem hints how small formals systems can't achieve agents desires. Anyway, I have only read the title not the arxig paper.

</comment><comment><USER45> Can't markets just assume that it is and move on. It's not like markets never do speculation /s

<comment><USER46> This is bad news for the technology business when those markets only 'efficiently' allocate capital to companies that attempt to exploit P=NP.

</comment></comment><comment><USER47> Somehow this seems to be a confusion of categories: markets are real-world mechanisms, while P and NP are mathematical abstractions. Does not compute. To the extent that it does, it's typical mathematical macroeconomic BS.

<comment><USER37> Since when do mathematical limitations not apply to the real world? Have you ever tried to square the circle?

<comment><USER48> Let's start with the fact that circles do not exist in the real world.

<comment><USER37> Well, that's a quite insubstantial point, to say the least. Mathematical theorems place upper and lower bounds on what is possible in the real world within almost every domain. Of course, there may often be _other reasons_ why something is impossible, too.

</comment></comment></comment></comment><comment><USER49> Does this also mean if we can prove that markets are efficient then P = NP?

<comment><USER50> Yes.

</comment></comment><comment><USER51> Even if P ist not equal NP, hardness of efficient markets could be in APX2 i.e. computing a solution that is at most twice as bad as the optimal solution is in P.

</comment><comment><USER52> Er, markets are massively parallel, yes?

Um, am I wrong in thinking that P and NP refer to non-parallel algorithms?

(Apologies in advance if I'm having a brain fart.)

</comment><comment><USER53> Profit is the measure of inefficiency in a market.

</comment><comment><USER54> free market efficiency is an evolutionary concept not accounting one. there's no intelligent design.

</comment><comment><USER55> First of all this paper leaves a lot to be desired in terms of rigor and it is for good reason not how mathematics is written by most mathematicians. It is very conversational and assumptions and derivations are jumbled together, while you sometimes find these in breakthrough papers from visionary mathematicians it often makes it harder to verify.

My understanding of the central argument in the paper is the following:

Definition: Let N be a positive integer denoting the length of the history, M be a positive integer denoting the number of assets. A market realization is an element of {-1, 1}^(NxM), i.e. M vectors of length n where all entries are either +1 or -1.

Definition: We call a function f: {-1, 1}^(TxM) -> {0, 1}^M satisfying f \circ s = s \circ f for s any element in the symmetric group S_M a technical strategy of lookback T. The symmetric group condition just states that permuting the vectors of length T among the M assets is the same as permuting the output the strategy. I.e. that the strategy has no inherent preferences among the assets.

The payoff of a technical strategy s on a market realization h is given by payoff(s, h) = \sum_{i=T}^N s(h_{i-T, ..., i-1}) \cdot h_i where the indexation is in the time dimension i.e. h_i denotes a length M vector. The budget of a technical strategy is budget(s) = max_{v \in {-1, 1}^TxM} s(v) \cdot (1, ..., 1). That is the maximal number of assets it wants to hold in any given state of the world.

Given a market realization h, positive integers B and K we say that h is (B, K) EMH-inconsistent if there exists a technical strategy s such that budget(s) <= B and payoff(s, h) >= K. If a market realization h is not (B, K) EMH- inconsistent we call it (B, K) EMH-consistent.

Claim (presented as a theorem in the paper): The problem of determining whether a market realization is (B, K) EMH-consistent is in P if and only if the knapsack problem is in P.

Claim: The weak efficient market hypothesis is true if and only if EMH- consistency is in P.

In the second part of the paper he indicates a model of an order book where he wants to encode 3-SAT as combinations of market orders. I do not understand how this is intended to work, i.e. if all information is available and incorporated into the market and the information generating process is stopped, and I have bid-offer spreads because of transaction costs, and I irrationally (remember I am not interested in the buying or selling the security, I am just interested in solving a 3-SAT problem, thus my actions should not influence the price generation process of an efficient market) enter an OCO-3 order to buy A, B or C at mid. Why should this result in a transaction? In the case (a or a or a) and (!a or !a or !a) I make one trade with myself in the case (a or a or a) and (b or b or b) and (!a or b or b) I make one trade with myself, but one of the problems is satisfiable the other is not. Now it seems obvious that by inventing new order types we can get order book rules that allow for complex computation to resolve clearing, however this is a problem with the proposed order types not the efficient market hypothesis? A (to me) equivalent avenue of investigation would be to imagine different order types such that to decide the clearing of an order book it would involve solving an undecidable problem - i.e. what are the most reasonable order types and order book rules such that we can encode the halting problem?

</comment><comment><USER56> Therefore it's false.

</comment><comment><USER57> That's why we need peer-review.

</comment><comment><USER58> The title of this post scores 10000 HN points.

</comment><comment><USER59> But markets are not efficient ...

<comment><USER60> Now this will degenerate into a fight between economists and computer scientists...

</comment></comment><comment><USER61> Efficient or not efficient, as long as it can make me rich, I'm OK with it.

</comment><comment><USER32> "For simplicity but without loss of generality, assume there are n past price changes, each of which is either UP (1) or DOWN (0)."

You know, this is the kind of thing that makes me wonder about how much quantum computation is going to change the game.

Where we aren't just calculating ups and downs but superpositions between the two.

<comment><USER62> Digital is a framework built on top of analog. Boolean logic is the foundation of all of our modern computing, and so we built all of our circuits around the ability to handle HIGH and LOW signals. What your describing seems to me like you're saying that leveraging an analog signal is the benefit of quantum computation. If so, I don't really agree. If not, then I misunderstood.

Either way, I suspect that the superposition between the change in value and the change in time, in relation to all of the other superpositions in value/time changes, is the true computational power of quantum technology.

</comment></comment><comment><USER63> Have another account here but don't want to take the karma hit for being a crank. I published this 2-page proof that the EMH is false:

[https://arxiv.org/abs/1011.0423](https://arxiv.org/abs/1011.0423)

(didn't set the date so in the document it's wrong, this was published 2010.)

It doesn't depend on P = NP, it's simply a rigorous proof that EMH is false.

Let's switch gears a second. Here's a famous elementary proof[1] that there are infinite primes. Suppose there are just finite primes, up to some largest. Multiply them together and add one. No prime divides the new number (because "every" prime leaves a remainder 1), so you've just produced a new prime. This new prime is larger than the largest prime in your finite set because you multiplied that by the rest of them and added one to get it. So this is a contradiction, you couldn't have had finite primes up to some largest.

Anyway if you think there might be a largest prime after what you just read, it just means you don't understand the proof. If you believe EMH might be true it just means you don't understand the proof that it is false.

Of course, nobody ever even hypothesized that academia was efficient :)

[1] [https://en.wikipedia.org/wiki/Euclid%27s_theorem#Euclid's_pr...](https://en.wikipedia.org/wiki/Euclid%27s_theorem#Euclid's_proof)

\--

EDIT: no mistake in my comment

<comment><USER64> Maybe I'm being super pedantic and possibly confrontational (I apologise in advance) but it jumped out on me here. I think you've misunderstood the 'famous elementary proof' that there are infinite primes. You do not create a new prime as you have suggested (quoted below).

 _" Multiply them together and add one. No prime divides the new number (because "every" prime leaves a remainder 1), so you've just produced a new prime. This new prime is larger than the largest prime in your finite set because you multiplied that by the rest of them and added one to get it."_

Instead you have created a number that may or may not be prime but definitely requires a new prime number (not in your set) to factorise it. Counter example: Take your set of prime numbers to be {2,3,5,7,11,13} then

(220.127.116.11.11.13)+1 = 30031

30031 factorises into 59.509 so you have found two prime numbers that are not in your original set.

EDIT: Responding to the edit above. The problem is that you claim that you make a new prime number by multiplying them all together and adding one. You didn't multiply all the numbers and added one to get the prime number, you multiplied all the numbers and added one to get a number (POSSIBLY NOT PRIME) whose FACTORS are prime numbers not in your original 'supposed' finite set. Your proof essentially lacks the step: IF new_number is prime: proof finished ELSE: factor new_number and show that at least one of the factors is not in your finite set.

EDIT 2: Counterexample number 2. Suppose your finite set of primes is {2,7} (2.7)+1 = 15 So you have found 3 and 5 as primes that are not in your original set and are SMALLER than the largest prime in your original set. This is now a second mistake in your proof. Whether you are trolling or just too arrogant to see the mistake/error I do not know.

<comment><USER65> You're entirely correct. A very ironic mistake/misunderstanding for the parent post to make.

Edit: I've thought about this a bit more, and you can save the parent post by prepending a result like "Every number larger than one is either prime, or divisible by a prime smaller than itself". In this case you can then assert that your constructed number is prime. However, this result requires its own proof and was not mentioned by the parent post.</comment></comment></comment>


Ask HN: Review Our Club's Site - <AUTHOR>

All summer our small team of 3 people has been working on the website for a small student organization at Pennsylvania State University. Our club hosts battles with Nerf guns, scavenger hunts, and other outdoor games. After 3 months of hard work we've finally finished our site and we're all curious what the experienced hackers here at HN think of it!
Our site is: http://urbangaming.org
Some tech specs: Everything on the site was done by our team of students. We use the CodeIgniter framework and phpBB to power the backend of our site. Our server is provided by Linode (seriously, the rock for donating the server!) and runs nginx.
Our goal for the site was for it to be professional, expandable, and stable. We believe we've reached those goals, how about you guys? <comment><USER2> This is a fantastic site from what I can see right away. I hope you guys can open-source this effort or package it into a ready to use cms for other clubs/organizations to use. Even if you charge for it I would be your first customer. Bravo.

Suggestions

 _The drop down menu is not necessary. The main item on the horizontal bar links to a page full of text. Your goal should be to maximize the percentage of content per page that is consumed. Your visitors will be happier.

Suggestion is to discard most of the text and replace with a clean graphical interface that contains the items in the drop down of the menu item linking to the page. Example, The games page would be a grid of boxes with each game listed and a picture above the name.

_Video and pictures need to be more front and centre instead of in their own category hidden under About Us. The entire menu is very logically laid out. But this should not be your aim. Show the user what they want first. Show the best content first.

 _The calendar doesn't need to be it's own menu item. In fact it should always be shown - maybe on the side bar to the right like on the front page - but do it on every page.

_ The Welcome text on the front page in the blue bar is really all the about us that people need.

 _You don't need a Home menu item.

_ I like the colors.

 _I like that it is not full of dynamic content or javascript.

Here is what I would change: _Front page: Banner and dynamic picture take tons of screen real-estate.

 _Make the title smaller. Add a caption to it to decribe the site. Delete the Welcome text. Replace the welcome text with a grid of 4 videos - the most recent or dynamic ones. The news posts should be trimmed. 2-3 short paragraphs max and only if you have to. Your front page is your one chance to convince new visitors to come out to an event. Service your existing users with news in other ways - email, or on the bottom of page.

_ Upcoming events and Keep in touch are perfect. Add your emails to the keep in touch and get rid of any other sections in the site where you list emails. Get rid of About us. Replace Register, Login, and About us with a login box and a Get Involved.

 _Remove Support. Have one easy to find line of contact for all Help requests. No FAQ. Nothing else. Either it's easy enough to figure out on my own or I should ask you. Otherwise I'll think I'm an idiot or being treated like one.

_ No Overview pages of any sort.

Keep removing text and pages until you absolutely can't anymore. Less is more. You're done when you can't get rid of anything else. That's when you know. Check out how youtube.com front page does it. It's good.

Hope this helps and good luck!

<comment><AUTHOR> Wow thanks for the feedback. We do have a little content bloat right now due to some over-eager Liberal Arts majors writing for us. We'll see what pages can be eliminated over time. The original idea for the page when you click on a section heading was to have a list of pages underneath but somehow that changed during the course of development.

The reason for the drop-downs isn't quite obvious right now but we run some big games through the site and we want to make all the functions available with minimal clicking from every page.

The reason the image cycle and welcome text on the front page is so big is because we really want to emphasize "This is what we do" and "This is where to join" on the front page. The news and upcoming events and everything is below the fold because it's not as important for prospective members.

Support section is kind of redundant, I agree.

We'll keep working and refining though, thanks!

</comment></comment><comment><USER3> I did the backend for this site, it was a great experience. I hope you guys like it!

</comment><comment><USER4> Your warning about IE6 is undismissable. Why go to the extra effort of deliberately blocking IE6 users?

An IE6 user is probably quite happy to view your site with a few layout problems. Please don't be a hater.

For what it's worth the site layout looked roughly OK through the opacity.

<comment><AUTHOR> We're worried about all of our features working on IE6 and it's just easier on us if we don't support it at all. I'll try to go ahead and make the warning dismissible though.

Also, Penn State won't let you connect to their network if you have IE6 (in their ToS) and overall our percentage of IE users is around 15%, IE6 users is exactly 0.

</comment></comment><comment><USER5> wow - mad respect; for taking a 'outside the box, crazy ' - 'never to old to grow up' idea - and not only make it happen; but in college, and then to build a website .. and spread it..

\- honestly; I feel old, and jealous - in the clubs I joined chicks weren't diggin it :/

</comment><comment><USER6> I am on the head of the team that developed this. Hope you guys enjoy checking it out.

</comment><comment><USER7> I'm in this club! This is a cool!</comment>


Race, IQ and Wealth - <AUTHOR> http://www.theamericanconservative.com/articles/race-iq-and-wealth/

<comment><USER2> Well, that wasn't what I expected from the URL and opening paragraphs. (Just re-read this comment, and it sounded sarcastic, to be clear: the article _really_ takes a different turn from what I expected)</comment>


Preserving italics in pastes from webpages - <AUTHOR> http://ludios.org/ivank/2011/04/preserving-italics-in-pastes-from-webpages/

<comment><USER2> Isn't the browser supposed to get this right automatically? Chrome does this correctly, no?

<comment><AUTHOR> If you're pasting italicized text into a plain-text editor, it's not preserved automatically. (Edit: updated my post to make the purpose clear.) You have to mutate the page yourself. But you're right, most browsers do handle this when pasting into RTEs like Word.

On a completely unrelated note, Word completely fails to preserve blockquote indentation. Plain-text editors do the same, of course. Maybe that's another thing to mutate?

<comment><USER3> Notational Velocity preserves bold, italic, and strikethrough specifically in its otherwise plain-text editor. All other attributes characteristic of "rich- text" editors are normalized to the current style. The result is a _styled_ editor without the annoyance of getting random unwanted paragraph/line spacing, colors, sizes, and kerning mixed in with your note.

<comment><USER4> Indeed. That's a common annoyance when trying to paste something from a site into gmail. Especially if you manage to copy part of a table, it's almost impossible to get rid of it again. Or you have to resort to first copying it somewhere else, then back, to "filter" it.

Things like that cause me to hate rich text editors without "underwater" view.</comment></comment></comment></comment>