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Copenhagen interpretation
Aug. 13th, 2014 06:36 pm* The inability to observe electrons without disturbing them means that our knowledge of electron behavior has limits.
Popper: This is a subjectivist interpretation. Actually, the limit is on the homogeneity of our experiments. He says that while we cannot reduce the scatter of individual particles, we can make much more precise measurements in order to determine the scatter.
Predictions are limited because of scatter, but retrodictions are not limited, and retrodictions are important because they allow us to test theories.
* The wave-particle duality of light
The wave nature of the electron is an inherent property of individual electrons.
Popper: The wave function is a property of the experiment, predicting patterns. To say that the wave function is a property of individual electrons is as if to call him a "Gauss-man" because the distribution of people living in his neighborhood is Gaussian.
Each particle is accompanied by a wave function, but that wave function is its propensity to behave a certain way under specific experimental conditions. Change the conditions and you might change the propensity field (or not, if it's an irrelevant condition). But this is a feature of life, not quantum physics.
* If the electron source is turned down to a very low level, so that electrons come out only one at a time, the interference pattern remains.
The electron is interfering with itself
The two slit experiment: a beam of one electron at a time heading toward a barrier with two slits will show an interference pattern. If you shine a laser on the other side of the barrier, the electron only passes through one slit. But the interference pattern disappears.
* The observation of an event affects its outcome.
Popper: If two particles collide and we measure one, we know a lot about the other without measuring it.
* Classical mechanics is deterministic:if two baseballs are hit consecutively with the same velocity from the same position under identical conditions, they will land in exactly the same place. The same is not true of electrons [My note: objective statement]. We have just seen that we cannot simultaneously know [My note: subjective statement] the position and velocity of an electron.
* We can't understand quantum physics because we can't visualize it in terms of familiar Newtonian mechanics.
Popper: BS. We understand what problems quantum physics is trying to solve and how it solves them. That's what "understanding" a theory means. Visualizing it with ease is irrelevant.
* At a classical level, the movement of gas molecules is often presented as unpredictable because of our ignorance.
Popper: Put a gas in an open flask. It will escape even if no one is around to be ignorant about it. This is entropy. And the statistical tendencies of the molecules to do this or that is an objective feature of the real world.
Popper: This is a subjectivist interpretation. Actually, the limit is on the homogeneity of our experiments. He says that while we cannot reduce the scatter of individual particles, we can make much more precise measurements in order to determine the scatter.
Predictions are limited because of scatter, but retrodictions are not limited, and retrodictions are important because they allow us to test theories.
* The wave-particle duality of light
The wave nature of the electron is an inherent property of individual electrons.
Popper: The wave function is a property of the experiment, predicting patterns. To say that the wave function is a property of individual electrons is as if to call him a "Gauss-man" because the distribution of people living in his neighborhood is Gaussian.
Each particle is accompanied by a wave function, but that wave function is its propensity to behave a certain way under specific experimental conditions. Change the conditions and you might change the propensity field (or not, if it's an irrelevant condition). But this is a feature of life, not quantum physics.
* If the electron source is turned down to a very low level, so that electrons come out only one at a time, the interference pattern remains.
The electron is interfering with itself
The two slit experiment: a beam of one electron at a time heading toward a barrier with two slits will show an interference pattern. If you shine a laser on the other side of the barrier, the electron only passes through one slit. But the interference pattern disappears.
* The observation of an event affects its outcome.
Popper: If two particles collide and we measure one, we know a lot about the other without measuring it.
* Classical mechanics is deterministic:if two baseballs are hit consecutively with the same velocity from the same position under identical conditions, they will land in exactly the same place. The same is not true of electrons [My note: objective statement]. We have just seen that we cannot simultaneously know [My note: subjective statement] the position and velocity of an electron.
* We can't understand quantum physics because we can't visualize it in terms of familiar Newtonian mechanics.
Popper: BS. We understand what problems quantum physics is trying to solve and how it solves them. That's what "understanding" a theory means. Visualizing it with ease is irrelevant.
* At a classical level, the movement of gas molecules is often presented as unpredictable because of our ignorance.
Popper: Put a gas in an open flask. It will escape even if no one is around to be ignorant about it. This is entropy. And the statistical tendencies of the molecules to do this or that is an objective feature of the real world.
