# AdeleneDawner comments on The Dilemma: Science or Bayes? - Less Wrong

18 13 May 2008 08:16AM

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Comment author: 22 September 2010 09:16:24AM *  9 points [-]

Why does my consciousness follow only one world?

It doesn't. It splits when the worlds split.

Why am I not conscious of the many-worlds but only of one world?

Because there's no communication between consciouses in different worlds, even if both of the consciouses are derived from the same T-x individual.

Comment author: 22 September 2010 09:57:07AM 0 points [-]

"T-x"?

Comment author: 22 September 2010 10:02:21AM *  0 points [-]

' T ' means the current, or relevant, specific time. I expected ' T-x ' to be understood as 'at some point in the past, compared to the specific moment in which the consciousnesses you're contemplating exist' - x seconds in the past, to be specific.

Comment author: 22 September 2010 11:35:56AM 0 points [-]

That does make sense. I had interpreted the "-" as a minus sign, and the only thing Google gave me was http://en.wikipedia.org/wiki/T-X

Comment author: 23 September 2010 10:58:31AM -1 points [-]

My consciousness does not split, it follows only one world. That is my experience and what I have to account for.

Comment author: 23 September 2010 12:15:35PM 1 point [-]

Let me be more precise.

The many-world interpretation is based on a wonderful mathematical description of all possible past and futures, an infinite set of all possibilities.

I am fine with that as long as one consider this as a description of the many possibilities of the world, useful for predictions. But this interpretation is more than that : it's claiming that this mathematical description is reality and that all these possibilities actually exist. This is not a scientific claim but a metaphysical claim.

In a sense, it claims that everything exists : the future, the past, other futures, other pasts, and so on. My question here is : at this point, what does "exist" exactly mean ?

That's why I talked about consciousness in my first comment - not to confuse everyone, but because in my opinion, the definition of existence is empirical and must involve consciousness at some point.

I feel that this model lacks a kind of "instantiation" to describe not every possibilities but what actually exists... And thus it should not be considered as a reality, but rather as a potentiality of which existence is the instantiation.

Comment author: 23 September 2010 01:11:40PM 3 points [-]

Starting with the assumption that this world-branch exists and has conscious people in it, there doesn't seem to be reason to believe that the different split-off branches would have less-conscious people in them, assuming they exist. For the other branches not to exist, there would need to be something special that privileges this one. I'm not sure what this would be like. The fact that we have ended up in the world-branch we have ended up doesn't seem very special, if the starting assumption is that all world-branches with people in them exist and have conscious people.

I'm pretty much basing my own intuition in algorithmic information theory. It's more complicated to define physics with the weird quantum stuff in them and then specify a single "real" world as the result of every quantum interaction, rather than to just define the physics with the weirdness, and not give any single world-branch a privileged status. Simple things are more likely than complex things.

Comment author: 23 September 2010 02:59:53PM 1 point [-]

One branch is priviledged : mine. It is an empirical fact.

I will repeat your argument with time, what seems wrong to me may appear more clearly :

"Starting with the assumption that the present instant exists and has conscious people in it, there doesn't seem to be reason to believe that different instants would have less conscious people in them, assuming they exist. For the other instants not to exist, there would need to be something special that privileges this one. I am not sure what this would be like".

That is a good argument indeed, but here is an empirical fact : only the present exists, other instants (past or future) do not exist.

That is exactly the same problem to me. The many-world just goes one step further by claiming than not only past and future events "exist" the same way that present exist, but also every alternative past/present/future. It does not account for existence.

Comment author: 23 September 2010 03:46:24PM *  0 points [-]

Given this line of reasoning, should I still believe that people other than me in this world-line are conscious beings instead of p-zombies, given that I have the privileged conscious viewpoint?

Also, I wonder if the "only the present exists" notion could be made to get into relativistic trouble in a similar way as the "only this world-line exists" seems to end up in quantum mechanical trouble.

Comment author: 23 September 2010 05:31:17PM 0 points [-]

I can communicate with other people, therefore I assume they are conscious. It's an empirical evidence, which leads to an inter-subjective viewpoint.

From this inter-subjective viewpoint, we can all agree that only the present exists, and only this world.

The troubles we can get with scientific models are always of the same kind: it is an instantiation problem. Scientific models do not say anything about existence, they are only good at predictions.

Comment author: 23 September 2010 06:24:08PM 1 point [-]

From this inter-subjective viewpoint, we can all agree that only the present exists, and only this world.

Sorry for the flip reply, but shouldn't that rather be "only that"?

I think I get your idea about the difficulty of assuming the reality of unreachable states, but you seem to keep making ungrounded jumps from intuitions to assertions of certainty.

Comment author: 23 September 2010 08:36:06PM -1 points [-]

You're right, there is no certainty, but my jumps are not totally ungrounded. We all experience a flow of time in a single world, and the many-worlds interpretion does not really explains it.

Comment author: 23 September 2010 08:50:10PM 1 point [-]

You're right, there is no certainty, but my jumps are not totally ungrounded. We all experience a flow of time in a single world, and the many-worlds interpretion does not really explains it.

It really does. At the level of everyday life branching explains our experiences exactly as well as a non-quantum explanation. When we happen to be using scientific apparatus our experience is better explained by MW.

Comment author: 23 September 2010 03:57:29PM 1 point [-]

here is an empirical fact : only the present exists, other instants (past or future) do not exist.

Is this really an empirical fact? How do you define the word "exists"?

Comment author: 23 September 2010 05:12:40PM -1 points [-]

Maybe it's not really an empirical fact, but then do you really think that past still "exist" and future already "exist" as well as present does ?

How to define existence ? That is the big question. What is reality ? Why has the past gone, and why isn't the future already there ? And why am I myself ?

I don't have answers, I only blame the many-world interpretation adepts to go straight to conclusions without addressing those deep questions, as if you could step into metaphysics starting only from a predictive mathematical model of reality.

Comment author: 23 September 2010 05:23:49PM 0 points [-]

I don't have answers, I only blame the many-world interpretation adepts to go straight to conclusions without addressing those deep questions, as if you could step into metaphysics starting only from a predictive mathematical model of reality.

Stepping into metaphysics from a predictive mathematical model of reality sounds like a step backwards to me!

Comment author: 23 September 2010 05:50:40PM 0 points [-]

I don't know if it is a step "backwards", as metaphysics encompass science. I would say it's a step outside. Anyway, that's what the many-world interpretation does in my opinion.

Comment author: 23 September 2010 08:47:54PM *  0 points [-]

Maybe it's not really an empirical fact, but then do you really think that past still "exist" and future already "exist" as well as present does ?

My position is very close to the position of Max Tegmark, Gary Drescher and other compatibilist B-theorists, so yes, I really really honestly believe that past and future exist as well as present does. At least in some sense of the word "exists", but this is not a cop-out, the sense I used it must be very similar to the sense you used it. There is another reasonable sense of the word "exists" (corresponding to Tegmark's frog's view), where only some of the past and present exists, and not too much of the future.

The point is, you have several choices about how to consistently formalize your vague statement, but whichever you choose, your "empirical fact" will be factually incorrect.

Comment author: 23 September 2010 09:27:21PM -2 points [-]

your "empirical fact" will be factually incorrect.

I really doubt it. how could you factually prove that the past or the future exist ?

Let's say my position is a very narrow version of Tegmark's view, and that I call "present" (with a certain thickness) the parts of the past and future that actually "exist".

Comment author: 23 September 2010 10:24:21PM 0 points [-]

First of all, I should have wrote "logically inconsistent", but "factually incorrect" sounded better. :) More importantly, it is possible that I misinterpreted what you wrote:

here is an empirical fact : only the present exists, other instants (past or future) do not exist.

I interpreted this as a positive statement that an observer-independent present does actually exist, hundred percent. This is in contradiction with special relativity, as someone else already noted. Reading other comments from you in this thread, it seems like this is not what you meant. It is more like you choose the second option of my dichotomy: the frog's view instead of the bird's view. I have no problem with that.

Comment author: 23 September 2010 05:55:40PM 5 points [-]

One often sees talk here of something called the "Mind Projection Fallacy". In essence, it is the error of taking something subjective and treating it as objective. A canonical example would be saying "X is mysterious", rather than "I don't understand X". That is, what ought to be handled as a two-place predicate IsMysteriousTo(X,N) (topic X is mysterious to person N) is erroneously handled as a one-place predicate IsMysterious(X) (topic X is mysterious, full stop).

One criticism that might be made of the position you are taking here is that you are falling into a form of the Mind Projection Fallacy. Try imagining Exists(X) as a fallacious one-place predicate and replace it with ExistsFor(X,N), i.e. X has existence from the viewpoint of observer N.

Similarly, you should say "X was instantiated at a point in time in my past, hence X currently exists from my viewpoint, and I expect X to cease to exist at some point in my future. Any other supposed X, existing on some other branch of reality, is not the X to which I refer."

This, as I understand it, is the way Kripke says that issues of identity and existence must be handled in modal logics.

If you can accept this viewpoint, then it is just a small step to realizing that the people you are disagreeing with, those who consider past, future, and all branches of reality as equally "real" are actually talking about the model theory for your modal logic.

Comment author: 23 September 2010 08:48:29PM -1 points [-]

My point is that this model theory is incomplete, because it does not fully explain my experience. The model lacks a kind of instantiation.

As a "model theory of my modal logic", it may have an heuristic interest, not an ontological one. In other words, it's fine as long as you consider it only as a descriptive/predictive model. It's not if you think it is reality.

Comment author: 23 September 2010 08:57:05PM 2 points [-]

But what is it that makes you think that your experience has privileged ontological significance? Is it that you think that instantiation from your viewpoint is isomorphic to instantiation from everyone else's viewpoint? Why would you believe that with any confidence?

Comment author: 23 September 2010 09:14:51PM -2 points [-]

my experience is the only thing I can assume as real. Everything else is derived from my experience. It is thus the only thing that needs to be explained.

Indeed I find it reasonable to assume that everyone else can claim the same for him/herself.

Comment author: 23 September 2010 09:29:56PM 0 points [-]

Indeed I find it reasonable to assume that everyone else can claim the same for him/herself.

Ah! "Reasonable to assume". One of my favorite phrases. There are many things which it might be reasonable to assume. Unfortunately for you, the particular thing you have chosen to assume is not one of them. Because you will probably agree that I am a member of the set of people you mean by "everyone else". But I assert that I do not and can not claim that my experience has a subjectively privileged ontological status.

Comment author: 23 September 2010 09:40:38PM -1 points [-]

I did not claim that my experience has a subjectively priviledged ontological status. This is your interpretation. I meant it has a subjectively priviledged epistemological status.

Comment author: 23 September 2010 10:44:42PM *  0 points [-]

In the great grandparent, you wrote

my experience is the only thing I can assume as real

Perhaps you use the word "real" differently than I do, but it sounded to me as though an ontological assumption was being made. And that you were then extending that private ontology-of-experience to everyone else by a further assumption.

I'm happy to let you be an empiricist who is epistemologically cautious about what you can know beyond personal experience. I'm less happy to allow you to limit what can exist to that which you can know. As Eliezer argues out in the posting, Occam's razor, properly understood, does not provide you a justification for this.

Comment author: 23 September 2010 10:00:40PM 0 points [-]

I do not believe your assertion contradicts quen_tin's specific claim either as intended or as worded..

Comment author: 23 September 2010 09:13:37PM 0 points [-]

This is a preaching to the choir kind of argument. I am very very impressed with it, but you should not be surprised that quen_tin is unimpressed.