At 05:04 AM 5/23/2005, you wrote:

On Sun, 22 May 2005, rmiller wrote:

I'm approaching this as a sociologist with some physics background so I'm focusing on what the behavior system perceives ("measures"). If all possible worlds exist in a superpositional state, then the behavior system should likewise exist in a superpositional state.

First, it looks like you are confusing the multiverse of QM with the plenitude of "all theories" or all UTM programs (Level 3 with Level 4 multiverse in Tegmark's terminology). Different level 4 worlds do not superpose, they don't relate to each other in any way, by definition.

"Behaviour systems" are complicated enough that it is a mathematical certainty that they fall in the second class.
That depends on how one characterizes them. I'm describing a behavior system that is described as a "snapshot" of interactions between elements. It's an abstraction, of course, but not all that far removed from, say, a snapshot of a neural net.

In which case there is no way to detect that the superposition is happening; for all practical purposes each world goes its own sweet way.

No. Probabilities differ by a small degree across z space, but there are not necessarily discrete differences. It would be "infinite" in the sense that a continuum is infinite, or that a line contains an infinite number of infinitesimals.

If there are say, 10 possible "worlds" available to the behavioral state (percipient) but each world differs from the other by elements that are not observed by the percipient, then the behavior system is under the assumption that interaction is taking place with a single, unified environment.

Recalling the Copenhagen interpretation: does Chicago exist if you happen to be by yourself in a hotel room in Des Plaines, IL? The answer is irrelevant until the behavior system begins to experience some aspect of Chicago.

The superposition properties depend on the information available in the whole system (e.g. your hotel room), not just the mind of the observer.
That's a very basic assumption, of course---one that cannot be proven without measurement. Obviously the source material (whatever that is) is available for the behavior system to define as discrete bits of information, but the hard fact is, we're assuming we know the mathematical characteristics of this "source material" when we really don't.

The world is constantly in close touch with itself.

Yes it is. But we have characterized this "matrix of information" based upon interesting experiments that study the mortar between the bricks (as it were). Inferring much more gets us into great discussions of whether the universe is really a big computer and leads to films like, well, The Matrix. As Abraham Kaplan (1964) said, "when we don't know something, we don't know it." And we really don't know much about the character of the information that constitutes "the world". Let's take a look at the assumptions about Chicago, for example:

For instance, if Chicago vanished in a large quantum fluctuation photons which would otherwise have been reflected from its streets to the clouds would be different.

We're assuming that photons (rather than probabilities) exist independently of our observations and measurements of them. While obviously something is "out there" that when measured will fit the profile of a photon, it's a stretch to suggest that it can exist *as we know it* independently of our observation. We don't know the properties of "out there" very well, so perhaps we shouldn't assume that "reflection" and even "distance" are relevant. Our observations that lead us to the concept of entanglement lead us to assume the entangled objects are separated by "distance" when distance is, let's face it, an abstraction. (There was only one article that has ever called "distance" into question, and it appeared in Omni magazine a few months before it's demise. I'll say it before you: Maybe that was the reason it finally failed---it was heading in the direction of Hume with no Descartes to rescue it.)

Hence photons leaving (assumption: separation) the clouds that land (assumption: separation) in fields 40 miles away (assumption: distance) would be different and so on. Very soon (within microseconds) the photons coming through your hotel window are affected, and you become 100% correlated with the state of Chicago (assumption: we know the phase state of Chicago---that it is commensurate with collapsed probabilities associated with a quantum fluctuation resulting in photons becoming separated with an object and impinging on another object, etc. Lots of collapsed probabilities here with no measurement in sight--and no proof that Chicago exists independent of individual measurement. It's not just a limitation, it's an assumption--and maybe an improper one. Broadly (I'm not talking about Copenhagen, here) we generally assume that because the object has been measured once, it exists thereafter. Does it? We assume that if everyone measures the object it exists for those who have not measured it. There's no proof for that. None. Zip. It's just a convenient assumption we make. In fact, one interpretation of the beryllium "watched pot" experiment shows that the percipient interacting with the "object"--in this case, the Be atoms being exposed to RF--is the principal observer. What of the rest of us? What mechanism links our world view to that of that particular principal observer? Obviously, there is one, otherwise, nothing would get done and the scientific method wouldn't work very well. But what is the nature of that mechanism? We really don't know. The only experiments to find out are usually performed by psychologists or physicists with an interest in consciousness--and we end up with vague terms like mathematics-free terms like "qualia."

  From your point of view, Chicago is either there or not.

From the isolated percipient's point of view, that which is unobserved may not necessarily *have* to exist. Two isolated percipients (behavorial scientists might call them a "dyad") observing Chicago from, say, the Hancock building may see different things, but what they see---and presumably what they share--are abstractions. They can't see into the buildings. However, they may be superimposed with situations in which they do observe, say, the deep-dish pizza in that little restaurant on Rush street. The sum of these collapsed probabilities across z space---and their interaction with the observations of others--- may constitute consciousness. Put another way, this connected fibre bundle of "measured probabilities" through z space---in conjunction with all others may constitute our shared reality. Viewing behavior systems topologically, I believe, can help answer questions about decoherence. In this view a behavior system exists across a continuum through "layers" of varied probabilistic environments. One set of layers (one lane of the highway) may be chosen based upon its utility. I suggest that the "hidden observer" phenomenon--the "executive" function found only under deep hypnosis may be a evolutionary structure that has developed over time to sample probabilities.

What if Deutsch is incorrect about contact between the various worlds?

i.e., what if quantum theory is wrong and a different theory applies?

That's not what I'm asking---no more than Godel proved all math is a waste of time. I'm suggesting that by viewing a behavior system topologically--we can better understand some of the results we are seeing--including those on the speculative side. Sheldrake's dogs who trot to the front door ten minutes before their master arrives may simply be sampling un-collapsed probabilities on either side of the one they inhabit. The remote-viewing folks may be tapping in to probabilities in which they visit the site or otherwise have an opportunity to view it. Not the same thing as a closed time-like loop, but, last I heard those things haven't exactly been ruled out, either.

But the only reason we have to believe this stuff is the evidence in favour of QM (which is pretty overwhelming).

QM is extraordinarily predictable, but it is not particularly good at explaining what is going on "out there." Quantum entanglement is a huge mystery. Do we have a good explanation of delayed choice? (As for "sci-fi" mentioned later) Cramer's transactional interpretation suggests communication between particles from future to past---he might be right, but I wonder if, as a kid he read Isaac Azimov's *End of Eternity*? In that novel, they weren't called "particles"--they were called "kettles." QM is *predictable*, but that doesn't mean we shouldn't seriously examine the model to see how it's quirkier aspects fit with observations in other fields. Psychologists and sociologists rarely take on QM (though some do); it's usually the physicist who tackles consciousness. As a result we have consciousness books out there that discuss "qualia" and quantum processes taking place inside microtubles, but nothing that directly addresses measurement. Check the indices in some of these books. Hilgard is never mentioned, and neither is Jung (who happened to be a friend of Dirac and was himself interested in QM.)

More to the point, if you happen to know why the mere act of measurement--even at a distance-- "induces" a probability collapse, I'd love to hear it.

Suppose the behavior system normally exists across a manifold of closely-linked probabilities, with the similarities forming a central tendency and the differences existing at each edge of the distribution?

Again, QM makes definitive (but difficult-to-understand) predictions about this.
I know.  That's why I brought this up.

Yes there is a manifold of possibilities, in fact an infinite number of them, for instance "configuration space" which is the manifold of all particle positions (3N dimensional for N particles), or "momentum space", the manifold of all particle momenta (also 3N dim).

Yes. Manifolds are part and parcel of the canon. We're talking about the same thing.

According to QM, the probability distributions in these manifolds are not independent, e.g. config and momentum wave functions are related by a Fourier transform.

I'm not sure I follow you there. A Fourier transform is a mathematical tool used to deconstruct a complex wave form into its component parts. Wouldn't it be more accurate to say that configuration and momentum wave functions can be *described* using Fourier transform? Even if the config, momentum etc. share equivalent wave functions, does that necessarily imply relationships? I don't mean to chase any rabbits down that particular trail, I'm only saying we often assume more than we know.

Your "central tendency" is just the wave function, which is peaked around some configuration of particles in any given branch.

Same argument. A wave function describes, and the central tendency (in say, a normal distribution) can be described as a wave function, certainly. But I would argue that the wave function itself is not the configuration.

What people generally don't factor into this is just how *BIG* 3N dimensional spaces are, when N is macroscopic. Even apparently minor differences, such as the presence or absence of a speck of dust, correspond to enormously large separations in configuration space.

Well, yes---if everyone on the planet measured every speck of dust there would be an enormous amount of data involved--and somewhat less, perhaps if one person measured every speck of dust (had he the time and funding.) But if all the dust specks exist as probabilities then we really don't know how much 3N space it takes up. Of course, it may require thousands of pages of mathematical description to nail down properly, but that's a limitation of the tools, not a limitation of the thing we're describing. Just because an "object" requires a lot of paper to describe it doesn't necessarily mean it takes up a commensurate amount of space. Space implies distance--greater the distance, bigger the space---but then what are we to make of entanglement--which seems to suggest distance is irrelevant. If distance is irrelevant, then maybe we're assuming something we shouldn't. We're trying to describe a circle using the quadratic formula when it can just as easily be described in terms of radius.

Although technically there is some (usually infinitesimal) amplitude for all configurations, the only way you can get a useful amplitude for two macroscopically different "worlds" is to amplify some quantum behaviour, in which case the wave function splits into 2 or more branches, each of which behaves more or less according to classical physics.

That's when we *measure* them.  The measurement of an object is not the object.

The "width" of the distribution for a single branch corresponds to ordinary microscopic quantum fuzziness.

Again, if we assume the variable position of a dust particle--for example--is the criteria for a discrete branching. There are other ways to describe branching that do not imply a discrete and individual "direction." Each point in space may involve a unit probability; the branching occurs when the behavior system interacts with enough of them to form a unique field of probabilities--resulting in a unique outcome commensurate with the environment. Maybe worlds branch as a result of observation and interaction.

Hence the branches don't overlap in configuration space (or in the space of any other macroscopic variable), and so can't communicate.

By that model, no. But again, we're talking about the limitations of measurement, and those limitations should not be the occasion to decide that "communication" cannot exist between worlds. We investigate a house, and that house includes two different rooms. The rooms are different and they are at opposite sides of the house. Worse, the house has been in an earthquake and a two inch gap exists between room 1 and room 2. We declare that the rooms are different, and are not even connected to each other. To describe one room in terms of the other results in an unintelligible mess. So, we decide there is no communication between the rooms--and ignore the fact that we've strolled through the entire house.

If the behavior system can perceive only a small chunk of information at a time, then it may be possible that each percipient really does live in his or her own little world---a small island of similar probabilities made"real" from the larger cloud of probabilities.

We are all in our own little worlds, but in an objective sense; the same is true for "non-behavior" systems, e.g. rocks.

In a different sense. A rock doesn't interact in the same way a behavior system does, and it doesn't change very much throughout it's history. There's very little evidence to suggest that rocks talk to each other and modify their activity as a result. You could probably say the same thing for some people, but generally, we interact with one another and (generally) we think. Rocks don't do that very well, either. If our thinking involves sampling probabilities (lanes) on either side of our world line, then we have it over rocks big time. We now have access to information that the typical rock (or mountain lion) may not have. We can call it hunches, or our "guardian angel" whispering in our ear. We can produce works of art that mimic what will be seen in the news months later, or in the case of the first nuclear test---the very next day. I'm not one to believe in ESP or precognition (necessarily). But this sort of thing can be explained as the behavior system simply being a part of and taking information from the "lane" next to the one it's on. The effect might be described as having a very wide specious present.

If we quantify a behavior system in terms of elements and interactions between elements, we arrive at a complex, but definable state. If that behavior system exists across multiple worlds that differ in minute details (i.e. a unobserved kitchen saucer moved an inch to the side) then the behavior systems would exist as identical entities (or, as my friend Giu P. would say, *shadows*) across the similar "sections." Employing a little math, the behavior system could exist as an object in Z space--not too different than a fibre bundle in topology. Differences among the realized probabilities among these "shadow worlds" might show up at each end of the normal distribution, but may be still be perceived by the behavior system as guesses or hunches, depending upon where the primary centre of the behavioral bundle is at the time. Psychology experiments in the 1980s suggest (to me anyway) that a psychological mechanism has evolved that helps the behavioral system "negotiate" this territory.

If this has anything to do with the basic laws of physics we have to replace QM.

Well, of course I would never suggest we "break" any of Newton's laws; and I don't recall either Bohr or Everett ever drafting any. QM is predictive; the math fits the results, so the results naturally fit the math. No one knows why it works that way, but it does. So, there is no need to replace anything. I'm not suggesting anything as outlandish as a particle traveling forward in time, then reversing itself and traveling backward (that's been done), or a light photon communicating with itself in the past. I'm only suggesting that we take a closer look at the measurement issue--and how the behavior system interacts with the world. A model of the behavior system as a topological object may explain things a bit.

Personally it sounds to me like great SF and very duff science.

Great SF requires the author of the novel to explain how the weird things happen. By those standards, QM is not even great SF. Just because we can predict something to a ten-digit accuracy shouldn't imply we know what is going on--any more than the Tribriand Islanders know why the sun comes up every morning. Worse, we seem to have largely given up on trying to understand QM--almost to the point where we're treating it like we treated Newtonian physics. Things happen that way because they happen that way. QM has become the new Classical Physics.

Coming soon to a theatre near you: "The Laws of Quantum Physics." Break them at your peril.

R. Miller

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