From: George Murphy <GMURPHY10@neo.rr.com>

Date: Mon Mar 23 2009 - 22:02:49 EDT

Date: Mon Mar 23 2009 - 22:02:49 EDT

Yes, & that's why I said "pretty good statistically."

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: Monday, March 23, 2009 8:57 PM

Subject: Re: [asa] Trees don't lie

*>I think one of the things that makes expert guesses, even with physics so
*

*>ineffectual is the observation (of someone whose quotation I can't find
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*>right now), that one can't predict the trajectory of a ball in a
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*>gravitational field unless you can predict what life will do. A batter
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*>hits the ball, and you can predict the trajectory up until the point at
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*>which a hand in a glove attached to a living being catches it and changes
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*>the trajectory.
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*>
*

*> Any system which has life in it, is hugely unpredictable.
*

*> ----- Original Message -----
*

*> From: "George Murphy" <GMURPHY10@neo.rr.com>
*

*> To: "Glenn Morton" <glennmorton@entouch.net>
*

*> Cc: "asa" <asa@calvin.edu>
*

*> Sent: Monday, March 23, 2009 8:51 AM
*

*> Subject: Re: [asa] Trees don't lie
*

*>
*

*>
*

*>> Glenn -
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*>>
*

*>> Very quickly, & as far as I have anything to contribute winding this up
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*>> for now -
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*>>
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*>> It's necessary distinguish between two things. (a) The basic dynamics
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*>> of a complex system which, to the extent we can model it mathematically,
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*>> require nonlinear equations, and (b) the analysis of some important data
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*>> about the system which may use various math approximations. Think of the
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*>> difference between Newton's laws and Kepler's. Many (though not all)
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*>> nonlinear systems display sensitivity to initial conditions so that we
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*>> can't predict the future state (i.e. the precise values of positions &
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*>> velocities for mechanical systems) far into the future. But we can
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*>> analyze data using various approximations and assumptions in order to
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*>> estimate certain important facts about the future bahavior of the system.
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*>> The latter seems to me to be what Hubbert did quite successfully.
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*>>
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*>> (BTW, it's easy from the math at the site I gave to see why the peak
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*>> occurs at the point where half the initial reserve has been exhausted -
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*>> in this approximation of course.)
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*>>
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*>> About the other systems (elections, MLB) I didn't say I "wanted"
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*>> equations. I said earlier that I don't think we can have a complete math
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*>> description of such things. But to the extent we do, or can use a math
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*>> metaphor, they're nonlinear. & there are knowledgeable people who can
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*>> make predictions that are not perfect but are pretty good statistically.
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*>> They don't do that by solving equations though. I agree with Plato that
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*>> God is a mathematician but he has other interests as well!
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*>>
*

*>> 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: Sunday, March 22, 2009 10:56 PM
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*>> Subject: Re: [asa] Trees don't lie
*

*>>
*

*>>
*

*>>> Hi George,
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*>>>
*

*>>>> Again you of course know a lot more about oil production than I. But
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*>>>> when I take a quick look at a discussion of Hubbert's math at
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*>>>> http://wolf.readinglitho.co.uk/subpages/hubbertmaths/hubbertmaths.html
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*>>>> I see a slightly wavy curve of P/Q vs Q and the phrase "Let us fit a
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*>>>> straight line to this set of dots from 1958 on ..." . Now I understand
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*>>>> that Hubbert's original analysis was more complex but what's being done
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*>>>> here looks like making the simplest - linear - mathematical description
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*>>>> of what is really a pretty complex phenomenon in order to predict, not
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*>>>> the precise future state of the system but one crucial feature of
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*>>>> particular interest. I would be very surprised if the real dynamics of
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*>>>> oil production - if we could have a precise mathematical description -
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*>>>> is really describable with strictly linear equations. If it is, please
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*>>>> enlighten my ignorance by showing me that it is or referring me to an
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*>>>> appropriate source.
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*>>> .
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*>>> I will absolutely grant that you know more math than I. But, Hubbert's
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*>>> equation works and it is linear. The situation in oil production is
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*>>> complex only because of political decisions made by country leaders to
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*>>> restrict production or open the taps. Hubbert predicted a world peak
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*>>> oil in 1995. The only reason that that prediction didn't happen was
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*>>> because in the late 1970s and early 1980s, the world became incredibly
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*>>> more energy efficient due to the high prices of oil. But all that did
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*>>> was push the peak back about 10-15 years. I think we have peaked
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*>>> because of the current down turn. We will never catch up again with the
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*>>> decline because we are not drilling as much now. we were barely keeping
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*>>> up with production when we were drilling all out. Now that we aren't,
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*>>> world oil supply, defined as the amount of oil coming to market per day
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*>>> will decline rather quickly. Buckle your belts.
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*>>>
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*>>>>
*

*>>>> Similarly for the other systems I mentioned. What is the justification
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*>>>> for saying that the dynamics of a presidential election or a MLB season
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*>>>> are linear? To the extent that the term is meaningful, I suspect that
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*>>>> the dynamics of all complex systems involving human beings are
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*>>>> "nonlinear." A group of 50 Indians confronting 50 Pakistanis isn't
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*>>>> just 50 times a 1 on 1 meeting between an Indian and a Pakistani.
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*>>>
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*>>> I didn't say that the presidential election was linear.
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*>>>
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*>>>>
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*>>>> In discussing elections it's significant that you put "equation" in
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*>>>> quotes - and never actually write down any. That's because you don't
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*>>>> have any. You have relationships that to some extent are
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*>>>> semi-quantitative but you don't have A = B relationships. & unless you
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*>>>> do, the terms "linear" & "nonlinear" can be used only in the loose (but
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*>>>> I hope meaningful) way I did in the previous paragraph. & since you
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*>>>> don't have real equations, the concepts of chaos theory can also be
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*>>>> applied only in a loose way - which is not to say that they might not
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*>>>> be of some value if you're careful.
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*>>>>
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*>>>
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*>>> George, those are the kinds of systems that Tetlock studied--those
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*>>> lacking the kinds of equations you seem to want. That is why experts
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*>>> aren't any good.
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*>>
*

*>
*

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Received on Mon Mar 23 22:04:02 2009

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