Does gravity slap us into reality?

[phank]

In this context, we are discussing probabilities determined by that which is physically possible. If I have observed that the coin is heads-up, it is no longer physically possible that the coin could be tails-up. If no observation of the coin has been made, it is physically possible that the coin is heads-up and it is physically possible that the coin is tails-up.

No, it is not. The coin is what it is. Your ignorance has no effect on the coin, and peeking doesn't either.

This is getting boring.

[Boxing Pythagoras]

Not so. Probability is properly applied to potential FUTURE out comes. Not to ignorance of past outcomes.

I would rather disagree with this sentiment. Probability is useful for gauging quite a bit more than just the future. It's also quite useful in analyzing both past and present.

[Boxing Pythagoras]

No, it is not. The coin is what it is. Your ignorance has no effect on the coin, and peeking doesn't either.

This is getting boring.

I've just flipped a coin, behind me. I haven't looked at it yet. Is it physically possible that the coin is currently heads-up? Is it physically possible that the coin is currently tails-up?

[oxmixmudd]

Yes, after the coin is observed to be in a heads-up position, you are wrong to say that there is a 50% chance that the coin is heads-up. We agree on that much. I'm talking about before the coin is observed to be in a heads-up position. Is it wrong to claim, "There is a 50% chance that the coin is showing Heads" before it has been observed that the coin is showing heads?

I think this in a grey area that is a consequence of colloquial generalizations of a precise mathematical concept. The coin is what it is. It's a bit misleading (though common) to say there is a probability associated with that particular flip after it has happened. Again, probability will help us to understand the distribution of heads and tails over a large set of flips, or it can help us define the odds so that the house will win (in the long run) at games where people bet on what a given coin flip will be. But it doesn't tell us anything at all about what a specific flip was.

Jim

[Boxing Pythagoras]

I think this in a grey area that is a consequence of colloquial generalizations of a precise mathematical concept. The coin is what it is. It's a bit misleading (though common) to say there is a probability associated with that particular flip after it has happened. Again, probability will help us to understand the distribution of heads and tails over a large set of flips, or it can help us define the odds so that the house will win (in the long run) at games where people bet on what a given coin flip will be. But it doesn't tell us anything at all about what a specific flip was.

Where is that underlined portion coming from? I have never asserted that it "tells us anything at all about what a specific flip was." In fact, I have explicitly attempted to divorce the two concepts, several times.

I am only and specifically talking about the probability of the coin's position, not the actuality of the coin's position.

[phank]

I've just flipped a coin, behind me. I haven't looked at it yet. Is it physically possible that the coin is currently heads-up? Is it physically possible that the coin is currently tails-up?

It is physically certain that the coin is one way or the other. Your ignorance does not change the state of the coin. Yawn.

I suspect the problems here are (1) playing games with the language obscures rather than illuminates the issue; which is (2) Exactly what is a quantum superposition? Seems clear to me that coins are inappropriate illustrations.

[phank]

Where is that underlined portion coming from? I have never asserted that it "tells us anything at all about what a specific flip was." In fact, I have explicitly attempted to divorce the two concepts, several times.

I am only and specifically talking about the probability of the coin's position, not the actuality of the coin's position.

No, you are talking about the probability that you guess the coin's state correctly. The coin's position has nothing to do with the probability of a correct guess.

I think Jim is on the right track here. Where possible outcomes are properly constrained (head or tails, nothing else) and where observation enables us to construct a distribution of outcomes over a very large number of trials, we can refine the quality of our guesses about any future trial.

What looks like "randomness" in the outcomes of flipped coins, rolled dice, shuffled cards etc. is actually a constellation of contingent factors unknown to us. If we were able to pinpoint and quantify every relevant factor, we'd need no probability calculations. So in practice, probability calculations are a way of characterizing a system that's not fully understood.

[oxmixmudd]

Where is that underlined portion coming from? I have never asserted that it "tells us anything at all about what a specific flip was." In fact, I have explicitly attempted to divorce the two concepts, several times.

I am only and specifically talking about the probability of the coin's position, not the actuality of the coin's position.

Again, probability doesn't apply - technically - to a specific outcome. You are trying to say that 'observation changes the probability'. That is only even colloquially true if I know what the observation is. Otherwise there is no change in probability associated with observation.

That is, if I flip a coin, the probability of the flip being heads or tails is 1/2. But if I look at the coin and it is heads, then colloquially we could say the probability is now 1 that it is heads. But that doesn't mean anything statistically in that context. The grey area is if I don't look and I try to guess. Probability then only helps me in that if I flip and guess over and over again, I'll be right about half the time.

Perhaps more succinctly: the probability is always 1 that it is what it is. And it is always 1/2 that it will be what it will be. Observation itself doesn't change that.

Jim

[phank]

Perhaps more succinctly: the probability is always 1 that it is what it is. And it is always 1/2 that it will be what it will be. Observation itself doesn't change that.

Jim

And if you could precisely specify every factor involved, it wouldn't even be a probability. If you hold out a brick and drop it, what is the probability that it will fall? In this experiment, you have enough data about the relevant factors to eliminate any guesswork. The coin flip is just like the brick drop in principle, but in practice you lack sufficient knowledge (which in principle is there, just not easily accessible).

[Boxing Pythagoras]

Again, probability doesn't apply - technically - to a specific outcome. You are trying to say that 'observation changes the probability'. That is only even colloquially true if I know what the observation is. Otherwise there is no change in probability associated with observation.

I've been framing this thought experiment in a very particular way, in order to keep the analogy as applicable to QM as possible. As such, I've framed it under the assumption that the only true potential observers to the result are the two people in the thought experiment. In real life, this is not the case. If I flip the coin, and it lands on the floor, the floor observes the coin's position. If it lands on the table, it is the table which observes the coin's position. However, for this thought experiment, I am assuming that nothing besides the two people are observing the coin, in any way. In such cases, it becomes far less clear what "actual position" of the coin actually means, which far better approximates the Copenhagen interpretation of QM.

I'm also defining the probability by that which is physically possible. If it is physically possible that the coin is heads-up, we factor that into the probability. If it is physically possible that the coin is tails-up, we factor that into the probability. I am assuming, for the sake of the experiment, that it is not physically possible for the coin to be on edge.

Coins, obviously, are macro objects. As such, they make rather imperfect analogies for quantum objects. I am attempting to formulate this thought experiment in a manner which makes it reasonably accessible, while remaining somewhat true to the actual process under discussion. Unfortunately, the only way to very accurately represent the quantum process is with mathematics, which would end up being rather confusing to most people.

[Sparko]

I've been framing this thought experiment in a very particular way, in order to keep the analogy as applicable to QM as possible. As such, I've framed it under the assumption that the only true potential observers to the result are the two people in the thought experiment. In real life, this is not the case. If I flip the coin, and it lands on the floor, the floor observes the coin's position. If it lands on the table, it is the table which observes the coin's position. However, for this thought experiment, I am assuming that nothing besides the two people are observing the coin, in any way. In such cases, it becomes far less clear what "actual position" of the coin actually means, which far better approximates the Copenhagen interpretation of QM.

I'm also defining the probability by that which is physically possible. If it is physically possible that the coin is heads-up, we factor that into the probability. If it is physically possible that the coin is tails-up, we factor that into the probability. I am assuming, for the sake of the experiment, that it is not physically possible for the coin to be on edge.

Coins, obviously, are macro objects. As such, they make rather imperfect analogies for quantum objects. I am attempting to formulate this thought experiment in a manner which makes it reasonably accessible, while remaining somewhat true to the actual process under discussion. Unfortunately, the only way to very accurately represent the quantum process is with mathematics, which would end up being rather confusing to most people.

I think that is the main problem and the subject of this thread. Macro objects do not react the way quantum objects do. In the double-slit experiment, the photons actually were in all positions at once, until a detector was involved. If you were to repeat the experiment with ball bearings, it would not work that way.

So a coin can't be in an indeterminate state. But why? That is what this thread was started to discuss.

[Boxing Pythagoras]

I think that is the main problem and the subject of this thread. Macro objects do not react the way quantum objects do. In the double-slit experiment, the photons actually were in all positions at once, until a detector was involved. If you were to repeat the experiment with ball bearings, it would not work that way.

So a coin can't be in an indeterminate state. But why? That is what this thread was started to discuss.

Absolutely. The only reason dice and coins and cards were brought up, at all, was in an effort to create a somewhat understandable analogy by which to explain the Copenhagen interpretation of QM.

Honestly, Copenhagen is not my own preferred interpretation of QM. However, it is certainly more widely taught and more widely accepted than my preference, and (as difficult as the Copenhagen interpretation is) it is far easier a concept to explain than the interpretation I like, which is why I chose to focus on it when answering Seer's question. My favorite interpretation of QM is called Two-State Vector Formalism, and involves the concept of retrocausality. As crazy as the idea that 'simply observing a quantum can affect that quantum' sounds, the idea that 'events which have not yet even occurred can affect things in the past' is even harder for people to grasp.

[phank]

Absolutely. The only reason dice and coins and cards were brought up, at all, was in an effort to create a somewhat understandable analogy by which to explain the Copenhagen interpretation of QM.

Honestly, Copenhagen is not my own preferred interpretation of QM. However, it is certainly more widely taught and more widely accepted than my preference, and (as difficult as the Copenhagen interpretation is) it is far easier a concept to explain than the interpretation I like, which is why I chose to focus on it when answering Seer's question. My favorite interpretation of QM is called Two-State Vector Formalism, and involves the concept of retrocausality. As crazy as the idea that 'simply observing a quantum can affect that quantum' sounds, the idea that 'events which have not yet even occurred can affect things in the past' is even harder for people to grasp.

But wouldn't you say that the proposed explanations aren't intended to explain these observations, so much as they are intended to guide research in the direction of testable hypotheses? For example, what test could be performed that would differentiate between Two-state vector formalism and Copenhagen, so as to allow us to dismiss at least one of these?

[Boxing Pythagoras]

But wouldn't you say that the proposed explanations aren't intended to explain these observations, so much as they are intended to guide research in the direction of testable hypotheses? For example, what test could be performed that would differentiate between Two-state vector formalism and Copenhagen, so as to allow us to dismiss at least one of these?

That's actually one of the major obstacles for supporters of certain interpretations over others. Since these are interpretations of a theory-- and not new theories unto themselves-- they are generally mathematically equivalent, which means that Copenhagen makes the same predictions as TSVF, which in turn makes the same predictions as Many-Worlds, which makes the same predictions as the Transactional Interpretation.

It's basically the particle physics version of the Glass-half-full/Glass-half-empty dilemma.

There are some physicists and philosophers of science who are attempting to work out ways to create testable predictions which might differentiate these different interpretations, but it is an incredibly difficult task.

[Truthseeker]

QM treats the past and the future on the same footing. Another way to say that is that the future is just as real as the past. Or, the probability distribution for a given object is not just spatial, but spaco-chronologic (spacetime), including the future of every living human being and possibly other beings.

I think the QM probability distribution represents something real, not like say statistics generated by a particular kind of experiment. That is, the statistics does describe reality somewhat, but what the QM probability distribution represents is more particularly real.

The QM probability distribution for the simple 2-slit experiment differs from that with an detector added. That explains why we get radically different outcomes.