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Burton on Physics and Freedom (c. March 16)

Important posts from Burton.. Will try to neaten it later. I've snipped the first leadin (from Gene).
--- Mary

[Gene said:]

> Physical processes follow certain laws. Their outcome is predictable

> and unvariable, it is compelled by their action, volition is

> not compelled but the functioning of free unfettered choice.

> "Natural" processes do not produce (in the sense of producing

> volition) they compell. That is what cause and effect are all

> about. Given the proper input a given output must result. If we

> are to trust science this has to be a universal truth, limit your

> variables and the results will be predictable n'est pas?

Ce n'est vraiment pas, mon vieux. Quite a few words flew by on this

topic about eighteen months ago, in a lovely thread on Anscombe and

quantum mechanics which I don't intend to reprise. (I have the whole

thing archived here, if DejaLewis wants it; a bit of searching on the

public Usenet archives will also turn up most of it.) In that thread,

I was trying to be coy and Socratic, a mode to which I return by

professional habit when I see people reasoning about physics from

wrong premises. Today, for better or worse, I shall instead essay

the experiment of setting forth some of the things I actually believe.

I do this on a gamble that I can make my point more concisely this

way; if it backfires on me and I find myself called upon to defend

the experimental underpinnings of 20c physics, I'm afraid I can't

promise to do more than redirect the queries to the appropriate online

physics FAQs. I apologize in advance for this.

Anyway, the problem here is that a profound ontological distinction

is being glossed over. "Nature", as we today understand it, can be

fully modeled by what we call a wavefunction. A wavefunction is a

conceptual entity whose shape evolves _unitarily_ (that's a fancy

word that roughly means "deterministically and reversibly") with time

in accordance with the laws of physics. We observe this wavefunction

indirectly by measuring certain "observables", which you can envision

as projections of the wavefunction (Plato's shadows?). The value of

the wavefunction at a given place and time is "the whole show", in

the sense that it contains *all the information* the universe contains

about its own current state. BUT, and here is where I must speak

flatly from authority if I am to be permitted to make my point, the

value of the wavefunction does _not_ determine the value of all the

observables, but only a spectrum of (variously probable) outcomes

for observation. So "predictable and unvariable" is precisely what

the outcome of physical processes are not.

For example, the universe can be (and often is) in a state where an

electron is 50% likely to be observed at location A, and 50% at

location B. We then make an observation, and 50% of the time we

"find that the electron is over there at A". What we mean by this

is that the universe (that is, the wavefunction)

electron at A (50%); at B (50%)

us not yet having looked

has evolved, _deterministically_, into

electron at A, us having seen it at A (50%)

electron at B, us having seen it at B (50%).

>From the "omniscient" viewpoint, that of the wavefunction, the

question of where the electron "really" is has just evaporated, even

though _we_, with 100% certainty, have a definite opinion on the

subject! Now, with this preamble, let me give my personal view on

this leviathan red herring called the Problem of Free Will. Let

us imagine that I have a choice between two actions, A and B. If

the causal laws of nature (which, be it emphasized again, act on

the wavefunction, not on the observables) cause

Burton in a quandary between A and B

to evolve unitarily into

Burton has decided to do A; Burton then did A (50%)

Burton has decided to do B; Burton then did B (50%)

then the probability that I have done what I decided to do is 100%,

and I have complete free will. (All the usual evolutionary arguments

for how I came to be a pragmatically functional being, for whom

Burton has decided to do A; Burton's body rebels and does C (0%)

is a rare event, are still in force. And these arguments are all

that is needed to defend the proposition that our brains sloppily

approximate right reason, in a general way, and thus to explode

Mr. Lewis's Miracles, III attack on naturalism.) Because I _always_

(100% of the time, in this simplified case) do just what I decided

to do, my will is totally free, not just from my internal viewpoint

but from that of the hypothetical observer. Ask Him what I am

"predestined" by the deterministic equations to do, and He can say

"well, both", or "A^HB" (here you must visualize a still small voice

saying "A" and "B" in superposition), or "Mu!" if He's been reading

too many koans lately. Or, most tactfully and most accurately, He

can say, "why, do whatever you like". If He's feeling talkative, He

can say to me (or, for that matter, to the electron, though it will

perhaps respond less interestingly to the auctorial comment!)

"I call heaven and earth to record this day against you, that I

have set before you life and death, blessing and cursing:

therefore choose life, that both thou and thy seed may live...."

That my wavefunction is predestined to evolve into a linear quantum

superposition of A and B is knowable to anybody who has access to

the state of my wavefunction (or even to mortals who know a lot of

my observables, in some cases). Whether _I_ will choose life is,

from even the omniscient viewpoint, entirely up to me.

Wavefunctions are |=======================================================

the dreams stuff is | Joshua W. Burton (847)677-3902 jburton@nwu.edu

made of. |=======================================================

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From: jburton@nwu.edu (Joshua W. Burton)

Newsgroups: alt.books.cs-lewis

Subject: Re: The Problem of Evil

Date: 16 Mar 1998 09:28:27 GMT

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darylgene@aol.com (Daryl Gene) wrote:

> Now I have to plow through a lot of Scientific Jargon and

> semi-comprehensible New Physics to see if I can direct it toward

> some useful end.

Seventy-two years old, for heaven's sake! For how many more generations

do you hope to talk about "physical law" while ignoring the experimental

reality of what physical law is all about? I'm a patient teacher, but

I don't think you'll ever see an accurate exposition of QM with any less

jargon than what I just threw at you. Catch it before it passes you by.

> What is our motive for doing so? Why should we want to pick modeling

> when observable reality is all about us?

Every time you make the leap from "I see a brown line with a green blob

on top" to "I see a tree", you are modeling. The models that you have

been using all your life turn out to be wrong. Infinitesimally wrong,

in the case of most everyday observables. Subtly but crucially wrong,

in the case of things like lasers and computer chips and superconductors.

Totally wrong, in the case of single elementary particles. Wildly,

outrageously, meaninglessly wrong, in the case of your (and Lewis's)

grand speculations about the epistemology of consciousness.

Why you should care is beyond me to say. Eventually even schoolkids

will get bored with you if you don't, but with the state of our schools

that might take a few centuries....

> In Hinduism as I understand it observable reality is not considered

> to be real either. Yet we must each day act on the premise that

> it is. Why, if this is so should we not conclude that it is

> irrational to postulate a reality behind the reality. Again

> what is the point?

This one's real simple: because experiment forces it on us. Quantum

superpositions and wavefunction interference effects are part of the

world we live in: that computer in front of you depends on them. If

it makes you feel better, I don't think the Hindus like it any better

than the Christians, or have any special advantage when it comes to

accommodating the experimental facts into their worldview.

Here's a killer experiment for you to ponder. Three cups, each with

a coin under it. Whichever two you lift up first are always opposite,

a head and a tail. How many times do you have to try this before you

concede that the coins were neither heads nor tails before you looked?

(This would be hard---not impossible, at least in principle!---to

arrange with coins. With electrons, it happens daily in the lab.)

> I am familiar with the problems of predictibility in particle

> physics but I was not refering to perspective problems. Are you

> saying that any given physical reaction could occur as the result

> of any input? at random? Will water now flow upstream in our

> mountains? Will ice form at 200 degrees C (wow Vonnegut would

> love it)? If your waveform or whatever is not consistant and

> predictable than the physicists, chemists and biologists etc. in

> this world are fools on a fools errand. As they base their efforts

> on finding reproduceable results.

The wavefunction is utterly predictable, given a known starting value.

But the observables, which are what your argument about free will is

going to depend on in the end, are not. An electron, prepared in a

precisely known state (ZERO randomness of input, in the most exact

mathematical sense), goes up, or down, in a magnetic field exactly as

it likes. The equations promise this, and experiment delivers.

> I have no idea why you put so much effort into this nor what you

> are attempting to say.

I put effort into it because it really matters. I hope to reach a few

people who do have ideas.

> If you are trying to say that we only apparently make choices

> when seen from retrospect and in fact we do not, then sir, you

> are nothing but a determinist and your arguments fail long before

> you get to your waveform and I trust Pistol would agree.

Not even close. As I said, you are often free to do A or B, just

as you like. (So is a raindrop, or an electron.) And no one before

the fact, not even a totally omniscient observer who knows the entire

deterministic future (of your wavefunction, that is) can tell which

you will choose. Plenty of free will for everybody. Got it?

> Removing the argument to an Uberwelt (sp?) simply allows you to

> say anything you want about anything.

An odd gibe for a humanist to make to a scientist! _You_ may be able

to say anything you want; as for us, we have to get the sums right.

From a rise in the rolling |=============================================

Brooklyn pastureland, he could | Joshua W Burton 847/677-3902 jburton@nwu.edu

see Skyscraper National Park. |=============================================

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