Nassim Nicholas Taleb Profile picture
Flaneur: probability (philosophy), probability (mathematics), probability (real life), Phoenician wine, deadlifts & dead languages. Uber rating ~4.9
Matt Pfefferle Profile picture zensky Profile picture Chris Huser Profile picture Combative Scholar Profile picture Greg Kalus Profile picture 294 added to My Authors
30 Jun 20
COVID-19
Just a reminder that something that keeps growing at 1% a day gets multiplied by 38 in one year.
Here is my code
No, it is not (1.01)^365 since I used Log[deaths date t]-Log[deaths date t-1] so my growth rate is the exponential one. Hece Exp[365/100]. Look at code above.
Read 3 tweets
20 Jun 20
HAYEK vs PSEUDOLIBERTARIANS

For those invoking "libertarianism" in front of natural calamities, some news for you: Hayek explicitly gives a role to the "state": protection against violence, epidemics, and natural disasters. Namely; TAIL RISKS.

He understood uncertainty/tails.
2/n
I am not saying 1) here is the authority of Hayek, or 2) Hayek was a "true" libertarian.
I am just fed up with sociopaths with reduced brain functions citing Hayek to justify their crackpot theories about the pandemic.
Period.
3/n
Pea-brained pseudo-libertarians (PBPL) attribute the loss of economic activity to the "lockdown" brought by "government", not to the virus
Few who are neither brain-dead nor PBPL wd voluntarily go expose themselves to viruses. Risk aversion is responsible for economic effects
Read 4 tweets
5 Jun 20
PHILOLOGY SYMPOSIUM AR THIS
The genius of Maestro Al-Jallad @Safaitic: he gets that if Future pple want to know how today's people speak, shd not look at academic books but FB conversations & foreign script

MY Q.
1-Discovering "Rab" is lunar not solar (ελ ραβ) not ερραβ. True?
2- Either, in 8th C Levantine Greek (and possibly Romaic "Rum" Greek), β was pronounced "b" or Arabic ب was pronounced "v". Unless it was a convention that switched "v" to "ف".
3- He got it. Bottom up linguistics vs top down.

Read 6 tweets
2 Jun 20
LOGICAL INCONSISTENCY DU JOUR
Someone said "if an old person dies of COVID, it's not a big deal because they could have died of someone else".
To be consistent, you must accept:
"If a someone kills an old person, it's not a big deal because they could have died of someone else".
2) Societies types: one for which a life is a life, another where life is some actuarial number.

Watch the ravages economics has done to modern societies: comes with scientism, pseudoutilitarianism, pseudocost-benefit analysis & ... moral decay.

As in Dostoyevski's Crocodile.
3)Do not disrupt the Silver rule: don't treat the older generation the way you don't want the next generation to treat you.
Civilization and group moral rectitude started with the Silver and Golden rules.
Geronticide is morally repulsive; only accepted in nouveau-riche societies.
Read 4 tweets
31 May 20
How you did in this pandemic, as a country, a village, a business, a group, or an individual, whether emotionally, economically, or morally, is an indication of how robust you are and how fit you will be for the next decades.
2/ Things that went intellectually bankrupt over the pandemics & will hardly recover:
Epidemiology
Fortune cookie (positive) "evidence" base science
Bureaucratic topdown structures: WHO, CDC, UK Group

Rent seeking academia can no longer be financed. Universities will crumble.
Read 2 tweets
30 May 20
The BS Vendors in probability.
For those who don't get my logic, here is a rank of knowledge in probability with level 0 Phil the rat🐁 @PTetlock and level 5 "Russian" probabilists.

Unless one is Level 4, errors in probability can be harmful.
The point is that Fat Tonys and grandmothers don't make the mistakes of those levels 0-3.
Corrected
Read 3 tweets
28 May 20
@EHSANI22 @wael_atallah @dan_azzi @tania_kallab @Decafquest @WaelChehab1 Because the Syrian state is not a state but a special interest group interested in owning the whole thing.
@EHSANI22 @wael_atallah @dan_azzi @tania_kallab @Decafquest @WaelChehab1 But you are right that things happen often with wars or shocks.
@EHSANI22 @wael_atallah @dan_azzi @tania_kallab @Decafquest @WaelChehab1 Or, as in the case of Lebanon, bankruptcy.
Read 3 tweets
27 May 20
Comment on the Cirillo and Taleb (2020) "Tail Risk of Contagious Diseases": the rate of growth of fatalities may be predictable but, by what seems to be a paradox (it's not), the quantity of fatalities is NOT.
It seems to be a paradox because r has a finite mean but X has an infinite mean.

cc: @spyrosmakrid @fotpetr
Clearer
Read 4 tweets
27 May 20
@Marcellenassif @joshua_landis @Rim_Turkmani @KarlreMarks Syria is an ill defined exoname.

What people orig. called "Syria" was the Hellenistic dominion around Antioch/Emesa, which didn't always include Damascus.
Expanded to West Aram
Syrion in the Ancient Testament = Anti-Lebanon (Srion ve Lvanon)
Syria doesn't mean Aram nor Srion.
@Marcellenassif @joshua_landis @Rim_Turkmani @KarlreMarks Nor does "Syria" mean "bilad sh sham" Sham being an exoname for Northern country.
@Marcellenassif @joshua_landis @Rim_Turkmani @KarlreMarks There is this disease by idiots with university position but no deep erudition to flow backward in time modern nation-state concepts.
Read 3 tweets
26 May 20
SYMPOSIUM ON RISK PARITY

Friends, in the wake of the road-rage by the lunatic of #AQR, @CliffordAsness, I will post short tutorial videos explaining the BS in theories of diversification.

I will answer Qs here.
Thread is v. technical. Nonscientific commentators will be blocked
The points presented by @CliffordAsness are far from technical. (BTW I am not blocking him so he can rebut as he wishes).

SYMPOSIUM on ELLIPTICALITY and how it cancels diversification

Read 6 tweets
24 May 20
Friends, we will be doing #RWRI 14 online.
To accommodate people overseas it will be 2 weeks (10 days) 8-12 am EST (2-6 PM in Agrigento, Sicily).
We still need to work out details and learn to use Zoom.
Meanwhile women scholarships are open. Please check realworldrisk.com
The date: most likely August
What are online fees for executive programs as % of the physical?
Read 4 tweets
23 May 20
Friends,
1st printing is pre-sold out so I can correct mistakes in MS for a quick 2nd printing that shd hit 10 d later. Comments welcome!
researchers.one/article/2020-0…

The discussion w/the lunatic of #AQR is my point that their entire analytic apparatus is incompatible with fat tails.
Forgot to reference the lunatic of #AQR, @CliffordAsness
Adding to book:
Foundation of Risk Parity is, officially: 1) finite and KNOWN variance 2) ellipticality.

Problem: variance is not projectable since kurtosis is patently infinite.
No ellipticallity since infinite higher order moments.
Also problem of preasymptotic behavior.
Read 3 tweets
22 May 20
This may take 5 min or part of the weekend.
(please no comments by non-math amateurs).
CHEATING: By simulation the base is ½ and converges quickly. We cannot use traditional methods because the "generator" function f has a second argument in it, here p.
Same for exponent. Seems impossible to solve the composition analytically.
Read 4 tweets
22 May 20
1/n
The great Mandelbrot despised Fama whom he found both clueless & dishonorable.

Fama was a French major & M supervised his thesis; they applied the Levy-Stable Distribution for markets (mistake since it's a limit not met preasymtotically).

Then Fama turned on M to use MPT.
2/n
Fama's reasons was that Fat Tails were "incompatible with the tools in social science".
It's like using the map of Tokyo in Mexico because "here is a map".
I actually wrote to Fama & got same HORRENDOUS answer.

Mandelbrot saw Fama never understood the CONSEQUENCES of tails.
3/n
Mandelbrot's contempt for Fama prompted to ignore story in book but it is revived by the connection to the *AQR lunatic* the disgusting @CliffordAsness

Fat tails invalidate the tools of finance and Fama is indeed by his own admission unscientific.

amazon.com/gp/product/154…
Read 5 tweets
22 May 20
@DrMichaelBonner Interesting: دمغهما as verb ( دماغ is brain in fus7a, head in Egyptian )
@DrMichaelBonner I always learn something when Michael Bonner is in the room.
THere is a verb دمغ for killing someone by hitting someone's brain tissue... Image
@DrMichaelBonner And I am very confused. The only Semitic root I know is דמע (tears from the eyes).
Read 3 tweets
21 May 20
Amici italiani,
Sto cercando un romanzo facile da leggere in italiano.
Sono stato sorpreso di scoprire che la Moravia è molto più ricca e difficile da leggere rispetto, per esempio, a Machiavelli.
Qual è il più semplice? Che ne dite di?
Barico?
Di Lampedusa?
Schiaschia?
Altri?
Com'e Eco in italiano? Facile?
Grazie amici!
L'autore piu suggerito qui e Calvino; e il piu facile da leggere?
Leggere la letteratura in una lingua straniera e molto difficile; qual e il libro piu semplice di Calvino?
Read 3 tweets
20 May 20
1/n
AQR issued 2 flawed reports saying tail risk hedging doesn't work (in theory), options are "expensive"

Yet they did not reveal that
1) Their OWN risk premia strategies lost money.
2) Their other public crap underperforms the MKT.

Insult to clients & the REAL WORLD.
2/n (#AQR)
Meanwhile Universa hedged portf outperformed SP while AQR crap and RISK PARITY junk underperformed. I cannot believe that AQR will issue claims from hypotheticals.

Further they are mired in the probability distributions & metrics that have been amply debunked.
3/n
Antti Ilmanen claims tails must be expensive from lottery tickets (but excludes 1987 crash); doesn't get basics: Stat 102 does't cover when assumptions are violated (Gauss-Markov, etc.)
Fails to get Bayes' rule.

Note: while RISK PARITY is ~unique, tail hedges vary hugely.
Read 13 tweets
19 May 20
1/ EDUCATION RESET
Model: university provides tutoring & examinations w/o teaching.
Tutors supervise student groups meeting periodically like a book club.
It makes no sense for a prof to lecture if you can get a better ones on web.
ht/@Confusezeus
cc:@PZalloua @polemitis
2/ #RWRI proved that experienced people are uniquely capable of teaching a real world subject: doctor trains doctor, nurse trains nurse (& doctor), risk takers train young risk takers (not some nerd), accountant train budding accountants, thief trains thief, prostitute trains...
3a/ You can learn yuuuuugely from Twitter while playing.
I learned
Inequalities frm Maestro Bogomolny (RIP) & the FB Romanians
Semitic philology frm @Safaitic & @PhDniX
Latin frm @ArmandDAngour
Computational math frm @WolframResearch
History frm @holland_tom @DrMichaelBonner
Read 3 tweets
17 May 20
We use negative probabilities in quant finance since probability is just a KERNEL inside an integral, rarely a "real thing" outside of binary payoffs.
So long as *no arbitrage* is satisfied.
Only thing that matters is (by scaling) ∫densities=1.
Similar to negative prices in oil.
2) To visualize the intricacy, see my comments #RWRI on negative prices via arbitrage/squeezes.

@johncarlosbaez
Here is the axiomatic framework for extended probability.
Read 3 tweets
13 May 20
ERRORS 101
Never produce a point estimate for risk management, esp. in a fat tailed domain, rather show statistical properties.
Never judge a risk management stance from point forecasts.

These errors are promoted by the Idiot of Pennsylvania, Phil the rat 🐁 Tetlock @PTetlock.
Paper with @DrCirillo forthcoming in Nature Physics later this week explaining the point, @mattwridley. Tail exponent <1, even possibly <½ means NEVER issue a single point forecast and NEVER present an average.
For pandemics if the average exists, about ~95-99.9% of observations would fall BELOW the average. Aside from the slow workings of the law of large numbers.

Should I explain this in a short video?
Read 4 tweets