Multiple Realities

the concept of "multiple realities" can be profitably and realistically applied to perspectivist notions of the multiple interpretations of "the world" as occurring in different individuals and different cultures.
Otherwise it must be confined to the mathematical adventures of quantum/string theorists.

Occam's razor strongly suggests there's only one reality

Trust me, I'm not saying I believe in multiple realities. It is a fascinating notion though, just as all science and philosophy is. What if's are more exciting than I know's. But we still can't count any belief or idea out no matter how logical or illogical it may be.

Just ordinary dreams and imaginations. Your brain in this "universe" would be isolated after a divergence; confined to the memories and sensory input of its specific body embedded in this particular world. Even though you or your consciousness might arguably be distributed across the multiverse as these various versions, there is no information exchanged among the latter. Max Tegmark (below) is one the most ardent advocates of the Everett progeny. David Deutsch (views discussed in bottom section) is another.

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In his 1957 Ph.D. thesis, Princeton student Hugh Everett III showed that this controversial collapse postulate was unnecessary. Quantum theory predicted that one classical reality would gradually split into superpositions of many (Figure 5). He showed that observers would subjectively experience this splitting merely as a slight randomness, and indeed with probabilities in exact agreement with those from the old collapse postulate (de Witt 2003). This superposition of classical worlds is the Level III multiverse.

Everett’s work had left two crucial questions unanswered: first of all, if the world actually contains bizarre macrosuperpositions, then why don’t we perceive them? The answer came in 1970, when Dieter Zeh showed that the Schroedinger equation itself gives rise to a type of censorship effect (Zeh 1970). This effect became known as decoherence, and was worked out in great detail by Wojciech Zurek, Zeh and others over the following decades. Coherent quantum superpositions were found to persist only as long as they were kept secret from the rest of the world. A single collision with a snooping photon or air molecule is sufficient to ensure that our friends in Figure 5 can never be aware of their counterparts in the parallel storyline.

Parallel Universes: http://space.mit.edu/home/tegmark/multiverse.pdf

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Q: When describing "Level III Multiverses", you state that on a quantum scale, all of the possible outcomes of a specific event actually happen, though each possibility occurs in a different parallel universe. We perceive that only one of the possibilities really occurred, as we are observers in only one universe. In this way, there is no randomness to the outcome of an event, as all possible outcomes happen. But is it randomness that determines in which multiverse-I, as a conscious observer, will perceive the event in?

Tegmark: That's a good question with a good answer: no, a different "you" will perceive (different outcomes of) the event in each of the parallel universes. Suppose a quantum measurement can produce outcomes 0 or 1. Then after the measurement, there's two parallel universes, each with a "you" with all memories you had before the measurement, one with the added memory of measuring "0" and one with the added memory of measuring "1". There's nothing random about this. Don't ask "how do I know which of the two guys is me?" - they both are.

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Q: Within the context of the multiverse, doesn't every conceivable physical possibility occur? If I'm driving my car and stop abruptly to keep from hitting a squirrel, don't I purposely run over that same squirrel in an alternate universe. And if so, isn't the number of universes that follow each outcome approximately the same?

Tegmark: No - and that's the crux. The laws of physics and your behavior evolved through natural selection create much regularity across the multiverse, so you'll try to spare that squirrel in the vast majority of all parallel universes where "you" are pretty similar to the copy reading this email (just as regards the above-mentioned gas station robbery). The fractions only split close to 50-50 for decisions that you perceive as a very close call.

FAQs: http://space.mit.edu/home/tegmark/toe.html

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. . . However, many worlds is not the only interpretation of quantum theory. Physicists can choose between half a dozen interpretations, all of which predict identical outcomes for all conceivable experiments.

Deutsch dismisses them all. “Some are gibberish, like the Copenhagen interpretation,” he says-and the rest are just variations on the many worlds theme.

For example, according to the Copenhagen interpretation, the act of observing is crucial. Observation forces an atom to make up its mind, and plump for being in only one place out of all the possible places it could be. But the Copenhagen interpretation is itself open to interpretation. What constitutes an observation? For some people, this only requires a large-scale object such as a particle detector. For others it means an interaction with some kind of conscious being.

Worse still, says Deutsch, is that in this type of interpretation you have to abandon the idea of reality. Before observation, the atom doesn’t have a real position. To Deutsch, the whole thing is mysticism-throwing up our hands and saying there are some things we are not allowed to ask.

Some interpretations do try to give the microscopic world reality, but they are all disguised versions of the many worlds idea, says Deutsch. “Their proponents have fallen over backward to talk about the many worlds in a way that makes it appear as if they are not.”

Taming The Multiverse: http://www.kurzweilai.net/taming-the-multiverse

Dale, I think the value of Occam's Razor applies more to the evaluation of competing explanatory propositions than to the ontological structure of the world.

Strange with MWI you thought of a possible baseball career and I thought of the girlfriends who got away in my life..........Here hoping that my wife does not read this post......

Doubtless JL you're right. My contention is more general, that the less evidence for a phenom the less likely it be

I'm sure there's a word for it

existant? (or maybe "actual")

No JL, more like "law of parsimony"

http://thesaurus.com/browse/occam's+razor?s=t

O.K.

Perhaps you are creating an alternate reality by imagining these things.. It is definitely interesting to think about

Occam's razor strongly suggests an infinite number of realities; it is the most economic way to explain the zoo of particular reality we face... the only alternative is to invite God what is a way too expensive option...

I agree with JL. We can say that there are as many realities as there are things to perceive a reality, but thinking that there are as many worlds as there are possible outcomes of all choices seems backwards to me. It makes more sense to think of these choices as what makes reality definite, instead of just being hypothetical potentials.

Still, I think I get where you are coming from. I sometimes get these impressions, for instance when I'm walking into a store, I might get a strong sense that someone is about to come out in a hurry, and we will crash into eachother. Was it a glimpse of an alternate reality? I don't know, and honestly, I don't think about it much.
But alternate realities happen all the time. We often do things one way, while thinking how we could have done it. If you picked your number and didn't win, and then someone picks the right number and wins, you know that if you had picked that number, you would be the winner. Alternate reality intruding. How **** you feel about it is a direct measure of how much weight you place in this alternate reality.

Yes, you are referring to alternative hypothetical realities, possibilities seen as acts of the imagination rather than logically or mathematically acquired probabilities. Both are independent of any empirical evidence.

It seems to me that reality is a matter of hypothetical possibilities most of the time. All choices you might make are possible realities until you make them. Everything beyond that moment, beyond the present, is hypothetical possibility.

Yes, I guess we can look at our notion of the future as a purely hypothetical ever-adapting worldview.

If you were seeing alternate you's, wouldn't it be depressing to think that some other 'you' did better? Hehe.
The way I think of it is there are many potential worlds. The present is the moment when all these potentials are realized.
When you make a choice, you eliminate all the choices you didn't make, so those potential realities never manifest.
When you see yourself differently based on a different path of choices, you could say that you are experiencing alternate realities. They can never manifest, but they can still exist as potential realities.

So instead of many worlds existing, you can perhaps think of many potential worlds which, when reflected in the mind of a sentient creature, are experienced as one reality.
We only enter this one reality physically. Our sentience remains aware of the many potential worlds.