Podcast 76: Godel, Escher, Bach and Bell's theorem

Home Forum Podcast and Blog Discussion Podcast 76: Godel, Escher, Bach and Bell's theorem

This topic contains 3 replies, has 3 voices, and was last updated by  Katfugue 1 month, 1 week ago.

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  • #2796

    Zampano
    Participant

    OMG guys, so much good stuff in the waning minutes of this episode (not that the rest was bad :))

    I laughed when you mentioned, in the span of a few minutes, Bell’s theorem, Godel Escher Bach, and PKD’s Exegesis. The former is a topic I had to write a paper on for a college course in quantum mechanics, and the latter two are absolutely two of my favorite books. GEB was actually given to me by a friend who is an actually PhD string theorist, and like a typical pseudointellectual, I have not finished it yet either, though I blame this largely on having misplaced the book for several years. I have a bit of an advantage though, having studied the kind of hardcore mathematical logic relevant to the stuff he’s frequently talking about. Btw, John, every other chapter of the book is actually a humorous little dialogue which totally could and should be acted out by someone… Oh and Hofstadter is a professor of computer science and cognitive science, definitely a smart guy, and he actually talks explicitly about Zen Buddhism a lot in the book, which I believe one of you mentioned.

    Anyway, on to the Bell’s theorem stuff. I’m not in the least a physicist, but a year ago I had the opportunity to take a class in quantum mechanics, and I wrote a paper on Bell’s Theorem. I’d be lying if I said I fully understood it, but the broad strokes are that entangled particles, typically electrons or protons in an experimental setting, must, as a single quantum mechanical system, must obey conservation of energy. So if, for example, you take two entangled electrons (“entangled”, btw, means they’ve interacted in such a way that the Hilbert spaces (basically infinite-dimensional vectors, I’m grossly simplifying all this) describing certain observable quantities cannot be separated from their composite Hilbert space) will have certain properties, e.g. spin (don’t worry about what spin is, just consider it an abstract concept (which it is)), that must be inversely related one another, so if electron A has spin up, electron B must have spin down (again, radical oversimplification). That all sounds fine so far. The catch is that this happens instantaneously, no matter the difference, which seems to violate locality, i.e. the universal speed limit set by light. This led people (Einstein, Podolsky, and Rosen, famously) to postulate that QM was an incomplete theory, that their must be additional information present in the electrons at the start of the experiment that predict what result will occur. What Bell showed in 1964 (all these papers are available for free on the internet, btw, have at it) is that you can be clever and test (not gonna get into that right now, but it involves setting detectors at different angles and performing hundreds or thousands of measurements) for the presence of these hidden variables. Since then, many people have verified Bell’s result in the lab, implying that their is a nonlocal (faster than light) interaction within quantum systems. However, in order to isolate this effect, the settings have to be chosen after the electrons (or photons) have been released from their source, to avoid possible local interference.

    So Bell test experiments show that the settings of the instrument doing the “observing” of the two electrons impact the results of one another, over arbitrary distance. One way to interpret this is “superdeterminism,” i.e. the sort of Calvinist idea that everything in the universe is determined ahead of time, hence the universe “knows” already which way the electrons will be spinning and which way the detectors will be set. But remember, these settings are made by computers, out of necessity for speed. So Hardy’s goal is to replace the computers with humans to test whether we still get this same effect. In essence, it is a test for free will. If the results were to remain the same it would, in my mind, imply that people’s behavior is completely determined from the beginning of history, which would of course have rather problematic implications for society.

    I hope that helps somewhat, it probably didn’t, but hey, I tried.

    -Zampano

    #2797

    John
    Participant

    Great stuff, Zampano.  The notion of freewill is a topic we’ve briefly touched on in a previous podcast. Proving it exists (or not) seems like the holy grail of science and philosophy.  Personally, the idea that we don’t have freewill really bugs me (for a whole host of obvious reasons), and it would have grave implications for society.

    Sam Harris gets into this and, although I’ve yet to read his book, I will (that is if it’s my choice) ;-).  Anyway, I wonder if he references this test.

    Definitely a topic for a full podcast.

    #2798

    John
    Participant

    BTW, just after I responded, this video by Stefan Molyneux popped up on my Youtube feed.  Short, but great stuff, and germane to the discussion I think. Molyneux has some great discussions on very controversial topics, political and philosophical.  What I like is that he’s willing to engage in these topics without fear of being perceived as politically incorrect.

    The important thing is the dialogue, and we’ve lost so much of that in today’s divisive culture.  I like that he’s attempting to bring that back.

    Now I’m wondering if I chose to watch this video or the Youtube algorithm and/or the “trickster gods” did it for me. 😉

    #3043

    Katfugue
    Participant

    <p style=”text-align: left;”>How did I miss this? GEB is one of my favorite books and maybe the top one. PKD’s Exegesis isn’t far behind either. Favorite Sci Fi writer for sure. I guess I need to re-listen to this podcast episode. All the stuff about Bell’s Theorem freaks me out as well. Or, more like all the things in life that can lead one to this theory freak me out. Unfortunately for my sanity, that doesn’t stop me from diving right in. Again and again.</p>
     

    Also…

    Curious what some of your other favorite books are Zampano. Do Hofstadter’s GEB and PKD’s Exegesis naturally go together? Feel free to reply or send me a PM. I could seriously use a new great book to get into.

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