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From: Christopher Maloney <dude.domain.name.hidden>

Date: Wed, 18 Aug 1999 22:37:38 -0400

Sorry it's taken me a while to reply to this post.

"Jacques M. Mallah" wrote:

*>
*

*> On Fri, 13 Aug 1999, Christopher Maloney wrote:
*

*> >
*

*> > I agree that the concept "that one's measure is somehow distributed
*

*> > among the so called computational continuations of one's brain activity"
*

*> > leads inevitably to the concept of near-zombies. The description of
*

*> > making a million copies of one person is a good illustration. Each of
*

*> > those copies has only a one millionth chance of "being" the original
*

*> > person, so we should not be as concerned when one of those dies as
*

*> > when someone else, who has never been copied, dies. But is this a
*

*> > refutation of the concept, by reductio-ad-absurdum? I don't think so.
*

*>
*

*> It is absurd to me and hopefully will be to the others. I think
*

*> you are not being objective since you usually find zombies absurd.
*

I should have qualified my zombie view in the post before, but I forgot.

If you re-read it, you'll notice that I always used the term "near-

zombies". I certainly do find the concept of zombies absurd. But "near-

zombies", as I was using the term, are physical SAS's that have a very

low measure of existence. That is, any random conscious entity would

have a low probability of finding itself to be that one relative to

others.

But "near-zombies" are not the same as zombies -- there is a qualitative

difference between low measure and not conscious (zero measure). I tend

to agree with Russell that it's difficult to see what measure has to do

with consciousness.

*>
*

*> > I want to clarify one thing, though, in Jacques' post:
*

*> >
*

*> > "Jacques M. Mallah" wrote:
*

*> > >
*

*> > > On Fri, 13 Aug 1999, Russell Standish wrote:
*

*> > > > > referring to
*

*> > > > > > t0 |
*

*> > > > > > |
*

*> > > > > > t1 T / \ H
*

*> > > > > > / \
*

*> > > > > > t2 / / \
*

*> > > > > > | | \
*

*> > > > > > t3 Y R B
*

*> > > > >
*

*> > > > > Assume that all three branches occur (two copying events).
*

*> >
*

*> > If there are two copying events, then there is no place for a coin
*

*> > toss to enter into the experiment, so the 'T' and 'H' should be
*

*> > erased from the diagram. The point is still made that, at time t0,
*

*> > Jane would figure:
*

*> > P(left branch, t1) = 1/2, P(right branch, t1) = 1/2
*

*> > P(Y, t3) = 1/2, P(R, t3) = 1/4, P(B, t3) = 1/4
*

*> >
*

*> > Which would imply that the two copies of her that saw red and blue
*

*> > would be less likely to be the same Jane at t0, so in some sense,
*

*> > they would be less human, you might say.
*

*>
*

*> In the QS claim, that is. T and H can still label the branches.
*

Okay as long as T and H are just labels, and there is no coin toss,

right?

*> The two experiments are actually rather different and I should
*

*> have made the distiction clearer in my post. I assume you refer below to
*

*> the case with two copying events.
*

No, I thought I was very clear. All of my six "options" are alternative

ways of interpreting the original experiment, with a coin toss, and one

copying event if the toss lands heads. There may be a problem with

terminology here, because if you assume the MWI, then the coin toss is

a copy event. I do usually assume MWI, so I may have confused things.

*> > 3. Subjective probabilities can be computed, but the assumption
*

*> > that consciousness can "flow" to a continuation independent of
*

*> > time or space is flawed.
*

*> >
*

*> > This, I think, is Jacques' point of
*

*> > view. Though he didn't state it, I would guess that he would
*

*> > say that
*

*> > P(H, t1) = P(H, t2) = P(H, t3) = 1/2,
*

*> > and that the original Jane would necessarily feel herself to
*

*> > continue along with her original body. That is, if, in the
*

*> > above diagram, at the copying event after Jane sees Heads, we
*

*> > assume that the original Jane is the one who is shown the Red
*

*> > card, then Jane at t1 would say
*

*> > P(R) = 1, P(B) = 0
*

*> > The copy of Jane who sees the blue card is a new person, who
*

*> > was just "born" at the instant the copy was made, even though
*

*> > she has all the same memories as the original.
*

*>
*

*> That is NOT my position, though of course I think 'consciousness
*

*> flowing to and being distributed among continuations' is nonsense. I make
*

*> no distinction between a copy and the original; 'identity' is not a
*

*> fundamental concept. Each has the same amount of measure. For practical
*

*> purposes the distinction is useful, however. It's just a matter of
*

*> terminology in the practical use.
*

Then I wish you would describe what you do believe. I am stymied in my

attempts to make sense of it, and I have tried.

Consciousness "flowing" is perhaps a bad image. I mean nothing more than

that certain observer moments are related by some sort of identity function

to other observer moments.

*> > 4. Subjective probabilities can be computed on the basis of the
*

*> > Strong SSA, and we get
*

*> > P(H, t1) = 1/2
*

*> > P(H, t2) = P(H, t3) = 2/3
*

*> > If this is the case, then I think we have to throw Tegmark's
*

*> > scheme using Bayesian statistics out the window. This option
*

*> > has severe metaphysical problems, though, in my opinion.
*

*>
*

*> I don't know what you mean by the above paragraph, but the
*

*> effective probabilities are correct if there are two copying events. The
*

*> SSA is the right way to do Bayesian calculations.
*

*> If the T-H split represented a non-MWI coin toss and was a one
*

*> time event, then P(H,t3) = 1/2. In practice those conditions would be
*

*> impossible to achieve even without the MWI of QM (e.g. in an infinite
*

*> universe) and P(H,t3) = 2/3.
*

It's very simple, although I guess I haven't written it out in gory

detail before. Tegmark's formula "for any mutually exclusive and

collectively exhaustive set of possibilities Bi, the probability of

an event A is given by

P(A) = Sum over i [ P(A|Bi) P(Bi) ]

I want to computer P(H, t3). Let B1 be (H, t1) and B2 be (T, t1), then

P(H, t3) = P(H,t3 | H,t1) P(H,t1) + P(H,t3 | T,t1) P(T,t1)

We assume in this option (4) that P(H,t1) = P(T,t1) = 1/2. Now, I

maintain, and I really don't see how it could be otherwise, that

P(H,t3 | H,t1) = 1 and

P(H,t3 | T,t1) = 0.

Some people have claimed that these relations do not hold, but I don't

see what they could possibly be talking about. These statements say

nothing more than that my memories are consistent -- that I can expect

them to remain constant. If we abandon that, then all hope is lost!

I wish those who claim this (Hal?, Wei?) would explain themselves better.

So, anyway, we get P(H,t3) = 1/2 by Tegmark's formula.

*>
*

*> > 6. Subjective probabilities can be computed, and we should expect
*

*> > the nonsensical results
*

*> > P(H, t1) = 2/3
*

*> > P(H, t2) = P(H, t3) = 2/3
*

*> >
*

*> > This is what I believe is probably true. I think that there
*

*> > must be a sort of "reverse causality" at work, which would
*

*> > increase the measure of the right branch of Jane at time t1
*

*> > (the branch that sees heads, but before the copy is made).
*

*>
*

*> Nonsense.
*

Whatever.

*>
*

*> > This still has Jacques' problem of allowing pseudo-zombies.
*

*> > If we switch to Jacques' example and assume two copying events,
*

*> > then the Jane on the left branch, at time t1, would have less
*

*> > measure than the Jane on the right (note the contrast between
*

*> > this result and the previous, where the Janes that were the
*

*> > product of the second copying operation were accorded less
*

*> > measure).
*

*> >
*

*> > But I don't see this as a problem. What I'm suggesting is that
*

*> > each human alive today has a varying amount of "measure". It's
*

*> > incorrect to assume that each person, when they are born, is
*

*> > given a single "measure unit". By my scheme, a person with a
*

*> > terminal illness with only a few days to live would have a
*

*> > very small measure of existence, relative to others.
*

*>
*

*> Huh? This seems inconsistent with QS and the specifics aren't
*

*> there.
*

This is my "near-zombie". We should not expect to find ourselves in the

body of someone about to die. We should not expect to land in the

hospital any time soon with a brain tumor and only a few days to live.

Now, note that this is consistent with QS. Just because the person

doesn't have a strong likelihood of survival, he or she does have a

non-vanishing likelihood, and will, therefore, necessarily find him

or herself surviving, by some extremely unlikely means. That's why

there's no such thing as a true zombie -- which would equate to

a conscious entity with a zero chance of continuing.

*>
*

*> > I can't help wondering, often, why I find myself to be the
*

*> > particular human I am. Do you others wonder this?
*

*>
*

*> You are arrogant. I am not a typical human but see no reason to
*

*> suspect I could not be a randomly selected human.
*

Tut tut tut. Why is it arrogant to wonder? The whole concept of the

SSA is about wondering why we are who we are.

*> > One thought
*

*> > I've had (please don't laugh at me too badly) is that the fact
*

*> > that I have a pretty poor memory might be significant. If I
*

*> > had a better memory, then my measure would be less, because
*

*> > fewer universes could have given rise to me. Of course, this
*

*> > reasoning probably won't work for you, but that doesn't make it
*

*> > any less valid from my perspective, which is the only one I
*

*> > have.
*

*>
*

*> Well I hate (giggle?) to say it but that sounds stupid. If you
*

*> remember something non-random, that shouldn't cut your measure. If you
*

*> remember a random bit, it cuts the total measure of each type of you in
*

*> half but now there are twice as many types. By total measure I mean, as
*

*> always, the number, so this is consistent with the SSA and leads to no
*

*> zombies.
*

But you said it yourself, if I remember a random bit, "it cuts the total

measure of each type of [me] in half." I don't know what you mean by

"type". I'd say it cuts the measure of me in half. That's exactly my

point.

*>
*

*> > I came to believe in this "reverse causality" while pondering
*

*> > the QS project I wrote about before. I started to expect that
*

*> > things would crop up in my way to prevent my being able to
*

*> > complete the project, before it came to fruition. It didn't
*

*> > (and it still doesn't) make sense to me that the measure of all
*

*> > my branches should be unaffected until the very instant that I
*

*> > carry out the experiment. Because if the assumption that I'll
*

*> > be alive after the experiment date is correct, then I can expect
*

*> > to have memories at that time of somehow having escaped. And
*

*> > I should, in general, expect to have a memory of "the most
*

*> > likely" escape route, or of one of the most likely ones, if there
*

*> > are several that are near-equally likely.
*

*> >
*

*> > But how can one reconcile that with the concept of continuity of
*

*> > consciousness from moment to moment? Only if there is a reverse
*

*> > causality at work.
*

*> >
*

*> > This theory has significant and testable implications. Viz: we
*

*> > should expect to find ourselves in a universe that will allow us
*

*> > to live forever. I.e. this leads directly to the requirement
*

*> > that the FAP is true. Just consider if time t1 and t2 are
*

*> > separated by a larger and larger time span. Consider also that
*

*> > those branches in which we cease to exist also tend to decrease
*

*> > the measure of all the observer-moments in previous subjective
*

*> > time.
*

*> >
*

*> > Basically, the measure of our observer-moments at the next
*

*> > instant in subjective time are weighted as the number of continous
*

*> > paths from that observer-moment to the "Omega-point". This is
*

*> > my crackpot theory. Though it's certainly hard to justify on the
*

*> > basis of the SSA on a moment-by-moment basis (the Strong SSA), I
*

*> > haven't yet found anything that contradicts it. I know that's
*

*> > not good enough, but anyway I find it the most satisfying
*

*> > result of the above thought experiment. All the other possibilities
*

*> > are problematic.
*

*>
*

*> The Omega Point CRAP is disproven because the universe is open.
*

*> (CRAP=causally retroactive anthropic principle)
*

Cute! But I thing the jury is still out. I probably shouldn't use the

term "Omega-Point", since that refers to a specific theory of the infinite

future evolution of the universe. I sometimes use it to refer in general

to the infinite future in which life continues.

*> - - - - - - -
*

*> Jacques Mallah (jqm1584.domain.name.hidden)
*

*> Graduate Student / Many Worlder / Devil's Advocate
*

*> "I know what no one else knows" - 'Runaway Train', Soul Asylum
*

*> My URL: http://pages.nyu.edu/~jqm1584/
*

Date: Wed, 18 Aug 1999 22:37:38 -0400

Sorry it's taken me a while to reply to this post.

"Jacques M. Mallah" wrote:

I should have qualified my zombie view in the post before, but I forgot.

If you re-read it, you'll notice that I always used the term "near-

zombies". I certainly do find the concept of zombies absurd. But "near-

zombies", as I was using the term, are physical SAS's that have a very

low measure of existence. That is, any random conscious entity would

have a low probability of finding itself to be that one relative to

others.

But "near-zombies" are not the same as zombies -- there is a qualitative

difference between low measure and not conscious (zero measure). I tend

to agree with Russell that it's difficult to see what measure has to do

with consciousness.

Okay as long as T and H are just labels, and there is no coin toss,

right?

No, I thought I was very clear. All of my six "options" are alternative

ways of interpreting the original experiment, with a coin toss, and one

copying event if the toss lands heads. There may be a problem with

terminology here, because if you assume the MWI, then the coin toss is

a copy event. I do usually assume MWI, so I may have confused things.

Then I wish you would describe what you do believe. I am stymied in my

attempts to make sense of it, and I have tried.

Consciousness "flowing" is perhaps a bad image. I mean nothing more than

that certain observer moments are related by some sort of identity function

to other observer moments.

It's very simple, although I guess I haven't written it out in gory

detail before. Tegmark's formula "for any mutually exclusive and

collectively exhaustive set of possibilities Bi, the probability of

an event A is given by

P(A) = Sum over i [ P(A|Bi) P(Bi) ]

I want to computer P(H, t3). Let B1 be (H, t1) and B2 be (T, t1), then

P(H, t3) = P(H,t3 | H,t1) P(H,t1) + P(H,t3 | T,t1) P(T,t1)

We assume in this option (4) that P(H,t1) = P(T,t1) = 1/2. Now, I

maintain, and I really don't see how it could be otherwise, that

P(H,t3 | H,t1) = 1 and

P(H,t3 | T,t1) = 0.

Some people have claimed that these relations do not hold, but I don't

see what they could possibly be talking about. These statements say

nothing more than that my memories are consistent -- that I can expect

them to remain constant. If we abandon that, then all hope is lost!

I wish those who claim this (Hal?, Wei?) would explain themselves better.

So, anyway, we get P(H,t3) = 1/2 by Tegmark's formula.

Whatever.

This is my "near-zombie". We should not expect to find ourselves in the

body of someone about to die. We should not expect to land in the

hospital any time soon with a brain tumor and only a few days to live.

Now, note that this is consistent with QS. Just because the person

doesn't have a strong likelihood of survival, he or she does have a

non-vanishing likelihood, and will, therefore, necessarily find him

or herself surviving, by some extremely unlikely means. That's why

there's no such thing as a true zombie -- which would equate to

a conscious entity with a zero chance of continuing.

Tut tut tut. Why is it arrogant to wonder? The whole concept of the

SSA is about wondering why we are who we are.

But you said it yourself, if I remember a random bit, "it cuts the total

measure of each type of [me] in half." I don't know what you mean by

"type". I'd say it cuts the measure of me in half. That's exactly my

point.

Cute! But I thing the jury is still out. I probably shouldn't use the

term "Omega-Point", since that refers to a specific theory of the infinite

future evolution of the universe. I sometimes use it to refer in general

to the infinite future in which life continues.

-- Chris Maloney http://www.chrismaloney.com "Donuts are so sweet and tasty." -- Homer SimpsonReceived on Wed Aug 18 1999 - 19:58:01 PDT

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