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How Can Probability Be Objective?

PeacefulChaos
Posts: 2,610
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4/23/2014 8:14:15 PM
Posted: 2 years ago
I've read that Heisenberg's Uncertainty Principle is not merely limited to our own perspectives but is actually part of reality. That is to say, electrons do not have a definite position before measurements are taken; however, I can't seem to find any other sources on this matter to help me better understand it. Could someone care to explain this? Because in my mind it doesn't make much sense.

If particles (more specifically, electrons) exist in reality, then they consequentially must exist somewhere in reality. In other words, they must have a place (and a speed) that goes with it. If one were to state that there is no definite position or speed of the electron before we observe it, then wouldn't this be akin to saying that object "X" did not exist until we observed it? Wouldn't this consequentially mean that reality is dictated by our own perspectives?

I cannot imagine how we could reach the conclusion that Heisenberg's Uncertainty Principle is an objective part of reality without studies of empirical evidence, which would be consequentially viewed through our own perspectives. Nevertheless, simply because I cannot imagine it does not mean it is not true, hence why I have made this thread.

If anyone could explain this phenomenon to me or point out if I've stated something that's incorrect, then I'd greatly appreciate it. Thanks.
PeacefulChaos
Posts: 2,610
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4/23/2014 8:15:39 PM
Posted: 2 years ago
At 4/23/2014 8:14:15 PM, PeacefulChaos wrote:
I've read that Heisenberg's Uncertainty Principle is not merely limited to our own perspectives but is actually part of reality. That is to say, electrons do not have a definite position before measurements are taken; however, I can't seem to find any other sources on this matter to help me better understand it. Could someone care to explain this? Because in my mind it doesn't make much sense.

If particles (more specifically, electrons) exist in reality, then they consequentially must exist somewhere in reality. In other words, they must have a place (and a speed) that goes with it. If one were to state that there is no definite position or speed of the electron before we observe it, then wouldn't this be akin to saying that object "X" did not exist until we observed it? Wouldn't this consequentially mean that reality is dictated by our own perspectives?

I cannot imagine how we could reach the conclusion that Heisenberg's Uncertainty Principle is an objective part of reality without studies of empirical evidence, which would be consequentially viewed through our own perspectives. Nevertheless, simply because I cannot imagine it does not mean it is not true, hence why I have made this thread.

If anyone could explain this phenomenon to me or point out if I've stated something that's incorrect, then I'd greatly appreciate it. Thanks.

When I stated, "Wouldn't this be akin to saying that object "X" did not exist until we observed it," I meant, "Wouldn't this be akin to saying that object "X" did not have a definite place or speed until we observed it?"
Sargon
Posts: 524
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4/23/2014 9:18:44 PM
Posted: 2 years ago
I myself have struggled with the idea that probability can be an objective feature of the universe. Heisenberg originally saw his uncertainty principle as an epistemological principle rather than an ontological principle. However, he later treated this probability as objective because Niels Bohr convinced him. When you read the letters that the two sent to each other, it is clear that Bohr was able to convince Heisenberg that the probability was objective based on logical positivism, which is a terribly flawed idea that is all but abandoned in philosophy. Physics is in a bad place conceptually because most physicists accept the objectivity of probability based on reasoning that philosophers gave up long ago. I find myself extremely skeptical of standard orthodox quantum mechanics, and I believe that a Bohmian interpretation is probably more justified. In this interpretation of quantum mechanics, probabilities are merely epistemic and not ontological (i.e. objective).
PeacefulChaos
Posts: 2,610
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4/23/2014 9:29:56 PM
Posted: 2 years ago
At 4/23/2014 9:18:44 PM, Sargon wrote:
I myself have struggled with the idea that probability can be an objective feature of the universe. Heisenberg originally saw his uncertainty principle as an epistemological principle rather than an ontological principle. However, he later treated this probability as objective because Niels Bohr convinced him. When you read the letters that the two sent to each other, it is clear that Bohr was able to convince Heisenberg that the probability was objective based on logical positivism, which is a terribly flawed idea that is all but abandoned in philosophy. Physics is in a bad place conceptually because most physicists accept the objectivity of probability based on reasoning that philosophers gave up long ago. I find myself extremely skeptical of standard orthodox quantum mechanics, and I believe that a Bohmian interpretation is probably more justified. In this interpretation of quantum mechanics, probabilities are merely epistemic and not ontological (i.e. objective).

I have to admit that I didn't know what logical positivism was and had to do a quick Google search (although, the name speaks for itself).

It would make sense, based off this idea, why Bohr would reach such an odd conclusion. Because we cannot empirically conclude where the electron is and how fast it is moving, the question consequentially becomes meaningless and probability is thus an objective part of reality.

Of course, this is fallacious reasoning, and I'm glad to know that this doesn't appear to be the case. Thanks for the answer.
Sargon
Posts: 524
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4/23/2014 9:32:23 PM
Posted: 2 years ago
At 4/23/2014 9:29:56 PM, PeacefulChaos wrote:
At 4/23/2014 9:18:44 PM, Sargon wrote:
I myself have struggled with the idea that probability can be an objective feature of the universe. Heisenberg originally saw his uncertainty principle as an epistemological principle rather than an ontological principle. However, he later treated this probability as objective because Niels Bohr convinced him. When you read the letters that the two sent to each other, it is clear that Bohr was able to convince Heisenberg that the probability was objective based on logical positivism, which is a terribly flawed idea that is all but abandoned in philosophy. Physics is in a bad place conceptually because most physicists accept the objectivity of probability based on reasoning that philosophers gave up long ago. I find myself extremely skeptical of standard orthodox quantum mechanics, and I believe that a Bohmian interpretation is probably more justified. In this interpretation of quantum mechanics, probabilities are merely epistemic and not ontological (i.e. objective).

I have to admit that I didn't know what logical positivism was and had to do a quick Google search (although, the name speaks for itself).

It would make sense, based off this idea, why Bohr would reach such an odd conclusion. Because we cannot empirically conclude where the electron is and how fast it is moving, the question consequentially becomes meaningless and probability is thus an objective part of reality.

Of course, this is fallacious reasoning, and I'm glad to know that this doesn't appear to be the case. Thanks for the answer.

The situation is that most philosophers of physics, as well as a minority of physicists believe that probability is epistemic and not objective. The problem in physics is that a majority of physicists still believe that it is objective and not epistemic.
PeacefulChaos
Posts: 2,610
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4/24/2014 9:23:34 PM
Posted: 2 years ago
To everyone who responded:

Thank you very much. I don't have the time to check all the sources you linked to me or respond quite yet, but I will when I get the time.

Once again, thanks.
slo1
Posts: 4,346
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4/25/2014 8:39:21 AM
Posted: 2 years ago
Try this:

Experiment:

* Shoot a small particle, say electron down a path. It reaches a mirror that it either reflects or goes through. 50-50 odds of reflecting or going through.
* If it goes through, it just goes straight in a box.
* If it reflects (say mirror reflects 90% angle to left. A little left of that mirror reflect it 90 degrees back so it is again parallel with the path when it goes straight through. Put a box at the end of that path.

Start the experiment:

*Shoot an electron:
* Go to one box and open it up to see which path the electron travelled. If I open the box at the straight path and see it in there, then I open the box on the reflected path and it will not be in that box. If I open the box at the straight path and the electron is not in there, when I open the box at the reflected path, it will be there.

Sounds good right? That is exactly what I would expect. Now lets stop looking in the boxes. Instead let's cut a slit in each box and put a wall behind the boxes to see where the electrons hit the wall. We would expect it goes down either path

* Shoot an electron.
* Instead of seeing a particle hit the back wall through one of the boxes we actually see a wave interference pattern, meaning the particle had to travel down both paths and through both boxes.

Wait.........how can that be? Before we demonstrated it was down one or the other paths not both. Now we show it went down both paths at the same time.

So the question then becomes where is the electron when I am not specifically observing for it? It is down both. If I were to look for it along the path before the box, it would be one path or the other, but not both.

That is an example of how principle of realism is in question. The particle goes down both paths until I observe it. Then it goes down one or the other. Thus before I measure it it has a probability of being in a particular position. When I measure it "chooses" a position to be in, but will no longer not be in all previously possible positions at the same time.