Re: [asa] Trees don't lie

From: Glenn Morton <glennmorton@entouch.net>
Date: Sun Mar 22 2009 - 20:12:32 EDT

Hi George, you wrote:

> If it isn't too presumptuous (because you know far more about this than I
> do), let me call attention to Hubbert's prediction in 1956 that oil
> production in the lower 48 would peak around 1969. It did in 1970. Of
> course that wasn't a precise prediction of the sort we can sometimes make
> in physics but it was more than just some average guy on the street saying
> "I think oil's going to start getting scarcer pretty soon." If you wish
> you can fill in some details on how Hubbert made that prediction but I'm
> guessing that it was with informed & intelligent extrapolation from data
> about known reserves, likely finds of new fields, oil consumption, &c. It
> wasn't by trying to solve some complicated set of equations.

If you look back at my qualifications on my statement, I specifically stated
that it was nonlinear equations which were unpredictable. Of course a
physicist will do a better job of predicting when a ball hits the floor than
a guy off the street. In the case of Hubbert's equations, they are linear
>
> & that prediction isn't unique. Political pollsters predict results of
> elections & often are quite accurate. Las Vegas oddsmakers make (in
> effect) statistical predictions about the likelihood of various teams
> winning the NCAA tournament, the world series, Super Bowl, &c. Sometimes
> they're wrong - not much of anyone expected Tampa Bay to be in the World
> Series or the Cardinal in the Super Bowl - but if they give 100-1 odds
> against some team winning, you're probably throwing your money away if you
> bet against them.

I think this is going way off the mark of where Tetlock's conclusions apply.
Every system he examines is a highly nonlinear system. So, it simply doesn't
prove him wrong by citing lots of linear equations or sampling theory.

> 2d, & less important for the basic question, don't overemphasize the role
> of nonlinearity in all this. Yes, many nonlinear systems display
> sensitivity to initial conditions but not all do. As the most obvious
> counterexample, a damped nonlinear oscillator will come to rest
> asymptotically, regardless of initial conditions. & while some of the
> systems you list, & especially those involving human beings, are very
> complex & it's in practice impossible to predict their precise state at
> all future times, we in fact have no differential equations, linear or
> not, that describe the dynamics of such systems. (What are the equations
> of motion of a US presidential election?) So while speaking of these
> systems as "nonlinear" may be a helpful metaphor it's no more than that &
> risks giving a more reductionistic picture than is appropriate.

I think non-linearity and systems with numerous feedback loops are precisely
what Tetlock is talking about, so, I don't think you can simply claim to
have disproven him by citing a lot of stuff that he doesn't talk about.

As to the presidential election, one has a whole lot of 'equations'. If our
enemies kidnap Americans 6 weeks before the election, the incumbent party
gets more votes. If candidate A gaffes and comedians laugh about it,
candidate A loses votes, If the market falls apart 6 weeks before the
election the party in power loses votes. If the pecadillos of the candidate
(his taste for sleeping with goats) comes out before the election, he loses
votes. If Al Qaeda beheads some movie star, Hollywood switches parties.
All these affect the election and they are conditional clauses with an
equation at the heart of the conditional. If candidate B disagrees
publicallywith the core values of their supporters, subtract X votes because
some of the supporters are going to stay home.
There are lots of relational equations that go into any election: if this
then add or subtract votes.

----- Original Message -----
From: "George Murphy" <GMURPHY10@neo.rr.com>
To: "Glenn Morton" <glennmorton@entouch.net>
Cc: "asa" <asa@calvin.edu>
Sent: Sunday, March 22, 2009 12:15 PM
Subject: Re: [asa] Trees don't lie

> Glenn -
>

>
> Shalom
> George
> http://home.roadrunner.com/~scitheologyglm
>
>
> ----- Original Message -----
> From: "Glenn Morton" <glennmorton@entouch.net>
> To: "George Murphy" <GMURPHY10@neo.rr.com>
> Cc: "asa" <asa@calvin.edu>
> Sent: Saturday, March 21, 2009 10:42 PM
> Subject: Re: [asa] Trees don't lie
>
>
>>I would say that the climate, the weather, political systems,, economics,
>>the oil markets etc, are all highly nonlinear. Tell me if it is going to
>>be raining where you are 33 days from now. Tell me what the price of the
>>stock market will close at on Monday. Tell me what the price of oil will
>>be April 23. Tell me what country will be our biggest problem in 2010.
>>All of these things involve nonlinearities.
>>
>> And I disagree that if one cant predict from them they won't be studied.
>> They will be studied because they are the real equations that govern this
>> universe and curiousity and hope that we can predict something will
>> ensure their study
>>
>> ----- Original Message -----
>> From: "George Murphy" <GMURPHY10@neo.rr.com>
>> To: "Glenn Morton" <glennmorton@entouch.net>; "William Hamilton"
>> <willeugenehamilton@gmail.com>; <mrb22667@kansas.net>
>> Cc: "asa" <asa@calvin.edu>
>> Sent: Saturday, March 21, 2009 7:34 PM
>> Subject: Re: [asa] Trees don't lie
>>
>>
>>> For a chaotic system one can't predict the future state of the system in
>>> detail for any length of time. But you can often make (a) statistical
>>> predictions & (b) thermodynamic predictions about the overall state of
>>> the system. Of course these are related. If all nonlinear dynamics
>>> could do was to say that we can't predict anything then people wouldn't
>>> publish books &c on nonlinear dynamics.
>>>
>>> Shalom
>>> George
>>> http://home.roadrunner.com/~scitheologyglm
>>>
>>>
>>> ----- Original Message -----
>>> From: "Glenn Morton" <glennmorton@entouch.net>
>>> To: "George Murphy" <GMURPHY10@neo.rr.com>; "William Hamilton"
>>> <willeugenehamilton@gmail.com>; <mrb22667@kansas.net>
>>> Cc: "asa" <asa@calvin.edu>
>>> Sent: Saturday, March 21, 2009 3:05 PM
>>> Subject: Re: [asa] Trees don't lie
>>>
>>>
>>>> George wrote Saturday, March 21, 2009 10:11 AM
>>>>
>>>>> I agree that in some fields "expertise" is overrated. It's pretty
>>>>> funny, in a gallow humors way, to hear the argument that financial
>>>>> firms have to pay big bonuses in order to hold on to the people whose
>>>>> "expertise" has driven the company, & maybe the country, into the
>>>>> ground. OTOH there's a populist temptation to debunk the idea of
>>>>> expertise because then "we're just as good as they are." & it's not
>>>>> clear that being able to predict the future is always the best
>>>>> criterion.
>>>>
>>>>
>>>> There is no doubt that a physicist knows the equations and where it
>>>> comes to deterministic systems, the physicist will do way better than
>>>> anyone else. But, most systems we humans deal with are decidedly NOT
>>>> linear or deterministic. They are non-linear. And one thing that
>>>> should have been learned, but apparently hasn't been by many in the
>>>> field of science, NO ONE can predict the state of a nonlinear system
>>>> after a certain period of time. The physicist is as helpless as the
>>>> plumber or homeless person and thus, all guesses will have the
>>>> equivalent chance of success.
>>>>
>>>> that is why experts differ on what the stock market will do, what the
>>>> weather will be like next week etc. And when it comes to global
>>>> warming, everyone is absolutely sure that they know what this grand
>>>> nonlinear system we call climate will do. They are acting as if it is a
>>>> linear system when it is decidedly nonlinear.
>>>>
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>

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Received on Sun Mar 22 20:13:30 2009

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