David Z. Albert is one of the leading popularizers of quantum mechanics, and
is on
this podcast:
David Albert is the Frederick E. Woodbridge Professor of Philosophy at Columbia University, director of the Philosophical Foundations of Physics program at Columbia, and a faculty member of the John Bell Institute for the Foundations of Physics. This is David’s eighth appearance on Robinson’s Podcast.
I think he is mostly known for trying to give a philosophical defense of string theory, in the absense of any evidence.
He tries to explain what is weird about QM
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what's often considered striking and unsettling about quantum
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mechanics is that at the beginning of the 20th century people start doing all
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kinds of experiments where unlike in the Newtonian case where we're just taking
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it for granted that yeah there're you know you look at these little dust Moes
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or something like that how they're moving around they themselves presumably consist of billions upon billions of
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these Elementary Point particles which we can't actually see we're sort of taking it for granted that things are
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going to work out in the beginning of the 20th century people fooling around with cathode ray tubes and and stuff
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like that begin to be able to keep track
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of the Motions of individual Elementary particles
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and these particles um um are behaving in ways that are almost
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inconceivably bizarre okay in
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particular people manag to convince themselves by doing lots of experiments
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with these Elementary particles that things like electrons for
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example could be in you you know um it's possible for an electron to be located
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at this point in space and possible for an electron to be located at that point
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in space those are the familiar Newtonian possibilities here or here or
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here or here or here what these experiments at the beginning of the 20th century suggested
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to people and I'm condensing here 30 years or so of wrestling with
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the with the results of these experiments in the beginning of the 20th century there are certain sets of
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experiments so-called interference experiments um double slit experiments
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if you can read about this want to read about this in the literature Neutron interferometry experiments stuff like
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that there's a whole um family of of experiments which
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slowly persuades people that um
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um that apparently there are certain states that
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electrons can be in electrons and neutrons and all elementary particles
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can be in um once again there's a possible state where the electron is at
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Point a there's a possible state where the electron is at point B what people became convinced of is that in addition
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there are possible states of electrons such that the very question is it
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located at Point a or is it located at point B or is it located at neither of
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them fails to make sense okay that um that the question that there are certain
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situations in which the question is the electron in box a or in box b or in
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neither of the boxes is like um is is is is like a
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question of the form um um is the number five Married
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okay or or what is the weight in grams of Catholicism okay or something like
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that um questions that philosophers often refer to as category mistakes okay
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um that there can be situations of a material particle an electron okay where
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asking whether or not it's in box a is somehow like asking what the marital
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status of the number five is or what the weight and grams of Catholicism is okay
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um this strikes people is absolutely bizarre people felt forced to
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conclusions like this because if you tried to tell the story of these
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experiments in a way that used locutions like well at this this point in the story the electron I suppose must have
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been here or at this point in the story the electron must have been there or even if you just insist that at this
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point in the story there must be some place where the electron was because after all it got from here in the
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beginning of the experiment to there at the end of the experiment it must have gone by some particular route either
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through this route or through that route you try to insist on that you try to tell yourself a story about how these
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experiments went okay that's consistent with the results you got you find that
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every particular Claim about which route the electron might have taken somehow collapses into nonsense becomes
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inconsistent with certain of the results of these experiments that you actually did okay so an idea grows
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up um um that it appears to be a feature
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of the way these fundamental particles behave that for every pair of states
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that such a particle could be in that is the state of being located at a and the state of being located at B there's also
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another radically unfamiliar but physically possible state which is
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referred to as the superposition of being located at a and being located at b or the quantum
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mechanical superposition of being located at a or being being located at and being located at B which is which
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which we can we can argue from our experiments is not a case of being
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located at a and not a case of being located at B and not a case of being
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located at both A and B as you often find in the popular literature when they
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try to talk about superposition and that's very bad too and that would reduce the mysteriousness of this way
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below what it actually is what these experiments suggest is that it is wrong
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to say under those circumstances that the electron is located at a and that it's wrong to say that it's located at B
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and that it's wrong to say that it's both at A and B and that it's also wrong
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to say that it is neither at a nor is it at B okay if you think there must always be a
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fact of the matter about where the electron is that exhausts the line iCal
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possibilities okay um um and so people felt
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forced um to acknowledge that what these experiments seem to be screaming at us
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okay is that for any two states that an electron could be in A and B there are
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other physically possible States in in in you know which can't be rightly
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characterized by saying that they're at a can't be rightly characterized by saying it's a b can't be rightly
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characterized by saying it's a both and can't be rightly characterized by saying it's a neither okay and rather you seem
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to be confronted with a situation in which um asking whether the
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electron is at A or B is like asking about the marital status of the number five okay it's just a
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nonsensical question good um
No, this is not weird. The same thing happens in classical mechanics. If you put a ball in a box
and shake it up, you do not know where it is. When you open the box, you find it in one position, and not others.
Why is it surprising that electrons behave this way, when classical balls do also?
He goes on to strongly attack Bohr for saying that it does not make sense to talk about the exact
location of an election in a box, until you open the box and look at it.
Then he praises various alternatives, such as hidden variables and many-worlds.
Bohr was right, and Albert is wrong. The electron is not a particle. If you ask for the exact location
of the election, you are basing the question on the faulty premise that the electron is a particle,
and it has no answer because it is a meaningless question. As Albert complains, the Physics community
accepted Bohr's philosophy about a century ago.
Albert is one of many QM expositors who argue that the textbooks do not make sense so there must
be something better. They are just wrong. The textbooks present a perfectly good theory,
and all the alternatives have horrible defects.
Sabine Hossenfelder is another one. She just posted a podcast on
Can Quantum Physics Explain Consciousness After All?
Her answer is No, of course, as she ends up saying Bell's Theorem requires superdeterminism.
She is a free will denier, but see the new paper Decision theory presupposes free will. You have to reject a lot of good science, if you reject free will.
