From: Glenn Morton <glennmorton@entouch.net>

Date: Mon Mar 23 2009 - 20:57:01 EDT

Date: Mon Mar 23 2009 - 20:57:01 EDT

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

right now), that one can't predict the trajectory of a ball in a

gravitational field unless you can predict what life will do. A batter hits

the ball, and you can predict the trajectory up until the point at which a

hand in a glove attached to a living being catches it and changes the

trajectory.

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 -
*

*>
*

*> Very quickly, & as far as I have anything to contribute winding this up
*

*> for now -
*

*>
*

*> It's necessary distinguish between two things. (a) The basic dynamics of
*

*> a complex system which, to the extent we can model it mathematically,
*

*> require nonlinear equations, and (b) the analysis of some important data
*

*> about the system which may use various math approximations. Think of the
*

*> difference between Newton's laws and Kepler's. Many (though not all)
*

*> nonlinear systems display sensitivity to initial conditions so that we
*

*> can't predict the future state (i.e. the precise values of positions &
*

*> velocities for mechanical systems) far into the future. But we can
*

*> analyze data using various approximations and assumptions in order to
*

*> estimate certain important facts about the future bahavior of the system.
*

*> The latter seems to me to be what Hubbert did quite successfully.
*

*>
*

*> (BTW, it's easy from the math at the site I gave to see why the peak
*

*> occurs at the point where half the initial reserve has been exhausted - in
*

*> this approximation of course.)
*

*>
*

*> About the other systems (elections, MLB) I didn't say I "wanted"
*

*> equations. I said earlier that I don't think we can have a complete math
*

*> description of such things. But to the extent we do, or can use a math
*

*> metaphor, they're nonlinear. & there are knowledgeable people who can
*

*> make predictions that are not perfect but are pretty good statistically.
*

*> They don't do that by solving equations though. I agree with Plato that
*

*> God is a mathematician but he has other interests as well!
*

*>
*

*> 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
*

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

*>
*

*>
*

*>> Hi George,
*

*>>
*

*>>> Again you of course know a lot more about oil production than I. But
*

*>>> when I take a quick look at a discussion of Hubbert's math at
*

*>>> http://wolf.readinglitho.co.uk/subpages/hubbertmaths/hubbertmaths.html I
*

*>>> see a slightly wavy curve of P/Q vs Q and the phrase "Let us fit a
*

*>>> straight line to this set of dots from 1958 on ..." . Now I understand
*

*>>> that Hubbert's original analysis was more complex but what's being done
*

*>>> here looks like making the simplest - linear - mathematical description
*

*>>> of what is really a pretty complex phenomenon in order to predict, not
*

*>>> the precise future state of the system but one crucial feature of
*

*>>> particular interest. I would be very surprised if the real dynamics of
*

*>>> oil production - if we could have a precise mathematical description -
*

*>>> is really describable with strictly linear equations. If it is, please
*

*>>> enlighten my ignorance by showing me that it is or referring me to an
*

*>>> appropriate source.
*

*>> .
*

*>> I will absolutely grant that you know more math than I. But, Hubbert's
*

*>> equation works and it is linear. The situation in oil production is
*

*>> complex only because of political decisions made by country leaders to
*

*>> restrict production or open the taps. Hubbert predicted a world peak oil
*

*>> in 1995. The only reason that that prediction didn't happen was because
*

*>> in the late 1970s and early 1980s, the world became incredibly more
*

*>> energy efficient due to the high prices of oil. But all that did was
*

*>> push the peak back about 10-15 years. I think we have peaked because of
*

*>> the current down turn. We will never catch up again with the decline
*

*>> because we are not drilling as much now. we were barely keeping up with
*

*>> production when we were drilling all out. Now that we aren't, world oil
*

*>> supply, defined as the amount of oil coming to market per day will
*

*>> decline rather quickly. Buckle your belts.
*

*>>
*

*>>>
*

*>>> Similarly for the other systems I mentioned. What is the justification
*

*>>> for saying that the dynamics of a presidential election or a MLB season
*

*>>> are linear? To the extent that the term is meaningful, I suspect that
*

*>>> the dynamics of all complex systems involving human beings are
*

*>>> "nonlinear." A group of 50 Indians confronting 50 Pakistanis isn't just
*

*>>> 50 times a 1 on 1 meeting between an Indian and a Pakistani.
*

*>>
*

*>> I didn't say that the presidential election was linear.
*

*>>
*

*>>>
*

*>>> In discussing elections it's significant that you put "equation" in
*

*>>> quotes - and never actually write down any. That's because you don't
*

*>>> have any. You have relationships that to some extent are
*

*>>> semi-quantitative but you don't have A = B relationships. & unless you
*

*>>> do, the terms "linear" & "nonlinear" can be used only in the loose (but
*

*>>> I hope meaningful) way I did in the previous paragraph. & since you
*

*>>> don't have real equations, the concepts of chaos theory can also be
*

*>>> applied only in a loose way - which is not to say that they might not be
*

*>>> of some value if you're careful.
*

*>>>
*

*>>
*

*>> George, those are the kinds of systems that Tetlock studied--those
*

*>> lacking the kinds of equations you seem to want. That is why experts
*

*>> aren't any good.
*

*>
*

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Received on Mon Mar 23 20:57:01 2009

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