Local Debates

I noticed that tomorrow (Tuesday, April 5) evening here in New York City there will be not one, but two debates involving theoretical physicists:

  • At 7 pm the American Museum of Natural History will host the 2016 Asimov Debate, with this year the topic Is the Universe a Simulation?. You can watch a livestream at that site.

    I confess that if this were a few days earlier, I would be convinced it was definitely a joke. But, it seems not, that instead this “has become a serious line of theoretical and experimental investigation among physicists, astrophysicists, and philosophers” and that it’s a “provocative and revolutionary idea”. One thing this is not is new. Nearly nine years ago it got a lot of media attention, and I wrote about it here (and here, where quite possibly my Message to Our Overlords kept them from turning us off). Sadly, the “blink” feature of html no longer seems to be supported, so the red text there won’t blink. Maybe it annoyed the overlords and they had it turned off.

  • Much further downtown, at the New York Academy of Sciences, at the same time there will be a panel discussion on a much more sensible and interesting topic What Does the Future Hold for Physics: Is There a Limit to Human Knowledge?. Also at 7 pm, livestream here.

    If I’d been asked (actually I was asked, and then unasked, a rather mystifying situation) for my views on this, I’d make the point that there’s no way to know what the limits will be to human understanding of physical laws. It has however become all too clear what the danger is of what will happen when we reach those limits. Instead of prominent theorists frankly admitting “we don’t know”, there will be an attempt to sell the story to the public that theorists have a wonderful, successful theory which describes everything, which sadly has the unfortunate feature of not making any falsifiable predictions. The string landscape/multiverse scenario now is being very aggressively sold as exactly this kind of endpoint to physics, to a large degree by people unwilling to admit the failure of string theory-based unification. There’s a very real danger that this will enter the textbooks, and that we will in our lifetimes see the end of fundamental physics as a human endeavor. The limit we will have hit will be due not to the nature of our minds, but instead the nature of our sociology.

    I suppose one other way of seeing if we’ve reached the end of physics would be if physicists started spending their time debating things like whether we live in a simulation. Oh, wait…

: At the NYAS evidently there was some discussion of the multiverse, with the audience told “The multiverse hypothesis is no more speculative than the universe hypothesis”.

Update: Clara Moskowitz at Scientific American has a report from the AMNH debate. At least there is one participant I agree with:

And the statistical argument that most minds in the future will turn out to be artificial rather than biological is also not a given, said Lisa Randall, a theoretical physicist at Harvard University. “It’s just not based on well-defined probabilities. The argument says you’d have lots of things that want to simulate us. I actually have a problem with that. We mostly are interested in ourselves. I don’t know why this higher species would want to simulate us.” Randall admitted she did not quite understand why other scientists were even entertaining the notion that the universe is a simulation. “I actually am very interested in why so many people think it’s an interesting question.” She rated the chances that this idea turns out to be true “effectively zero.”

One thing I’ve noticed about these kinds of things: they often feature physicists going on about mathematics, but mathematicians are never invited…

Update: The Asimov debate is available here, the NYAS one here.

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66 Responses to Local Debates

  1. Confused says:

    Sorry for the typos:
    I meant “….to go through the program…” not “….to go throw the program…”.
    There must be a virus in my simulation, or else that it should be upgraded. 🙂

  2. Zoviyer says:

    Peter, related to the last sentence in the second update. Kontsevich in the 2015 breakthrough prize Math Panel (you can watch this around minute 19 of the video that is publicly available in YouTube) said he believes we’re in a simulation but in this case because he doesn´t have a good explanation of why the mathematics of quantum mechanics work.

  3. Peter Woit says:

    Thanks. That may just be Kontsevich’s sense of humor. At least I hope that’s what it is…

  4. Jim says:

    It is kinda odd because saying we are living in a simulation is really identical to saying that God exists, but none of the participants wanted to go in that direction. It wasn’t even brought up. I guess some physicists are more comfortable with master computer programmer than they are with a God.

  5. zzz says:

    yeah, really, really strange, its like they think “The Matrix” is a plausible historical documentary

  6. Fred P says:

    The main problem I have with Universe as a simulation conjectures is that the hardware requirements would be enormous (i.e. ludicrous).

    Let us suppose 1 x 10^80 particles in the “simulated” universe. The memory requirements alone to track each particle would be at least the same number of particles in the “real” universe. Furthermore, these particles would have to be organized in a way that communication and processing can occur in finite times between many of these particles, and so that they are not dense enough to prevent organized motion. I guess I could do the math directly, but this is plainly infeasible; we are proposing creating a computer with more mass than the observable universe into a space far smaller than a galaxy. It would quickly collapse under its own gravity.

    One could argue that one has an algorithm that reduces these memory requirements by, say, 10 billion or so (which is highly infeasible). We are still talking about trying to create memory for a computer that far exceeds a galaxy in size, and needs to be compressed into a relatively tiny space (compared to a galaxy) to function, without having gravitational collapse.

    Even if the memory requirements were met by, say, having a constellations of close galaxies somehow communicating with each other, each having their own local processing of information, that just makes the problem even worse – since the cost of the Turing-like machine is then replicated in many different places, each of which requires significant mass, and additional communication problems.

    I don’t see this working without positing (for no reason other than to support this conjecture) wildly different physical laws, and deity-like powers on the simulators, in which case why would they be simulating our wildly different universe?

  7. Chris Oakley says:

    Re: “The Matrix” – how could the machines who created this simulated world for humans while simultaneously harvesting their body heat and brainwaves be sure that some other even more advanced race was not doing the same thing to them?

  8. Mitchell Porter says:

    Robert – you can tell him about testing a theory. Particles have masses and charges, and in string theory those properties come from the shape and size of the extra dimensions, etc. The crowning achievement of string theory would be to explain the specific mass, charge, etc. of the particles we actually see, but that hasn’t happened yet.

  9. G.S. says:

    Fred P.,

    From the 2012 paper by Beane, et. al (http://arxiv.org/pdf/1210.1847v2.pdf):

    “… the discovery of the string landscape, and the current inability of string theory to provide a useful predictive framework which would post-dict the fundamental parameters of the Standard Model, provides the simulators (future string theorists?) with a purpose: to systematically explore the landscape of vacua through numerical simulation. If it is indeed the case that the fundamental equations of nature allow on the order of 10^500 solutions, then perhaps the most profound quest that can be undertaken by a sentient being is the exploration of the landscape through universe simulation.”

    So, evidence that we are inside a simulation would be evidence in favor of string theory. However, lack of evidence that we are inside a simulation has no repercussions for string theory.

  10. vmarko says:

    Now I’m getting confused — is the multiverse inside a computer simulation, or is the computer simulation part of the multiverse? Or is it somehow both at the same time? Oh string theorists, please help me understand this deep physics!


  11. Low Math, Meekly Interacting says:

    That’s what so mind-blowingly awesome about about it: you can have a simulated multiverse embedded in a real multiverse, or another simulated one! I think infinity x infinity makes anthropics a googolplex times more plausible, don’t you?

    I don’t get all the hate for the simulation hypothesis, though. What if the simulators are advanced humans? They might be interested in us because they like to simulate alternate versions of their past. Maybe they can simulate a quantum mechanical universe and solve problems associated with the embedded lattice QCD or whatever because they’ve coupled the simulation to a “real” quantum mechanical experiment or quantum computer. Anyway, there are probably ways to deal with any of the sundry criticisms and perceived implausibilities. In my mind it puts the simulation hypothesis on firmer ground, scientifically. There must be a non-zero probability the simulators will eventually plaster “Oh, all right, you got us; yes, you’re a simulated brain in a fancy jar” across the heavens before rebooting. There’s zero probability we will observe other bubble universes beyond our causal horizon. Which is where they all must be, apparently.

    Not that either is more useful for solving current problems with physics, nor more or less ridiculous to debate professionally.

  12. Peter Woit says:

    I’m now deleting any more comments explaining why the simulation argument is stupid. Yes, it is. Comments about the panels are fine, what’s intriguing here I think is why very smart people are involved in such a dumb argument, not the argument itself.

  13. anon-e-mouse says:

    Having programmed for most of my life the temptation to see the world through the eyes of coding is irresistible (“What the heck is the state machine for this flower?”). I get that, it makes sense, it is my suspicion that all immersive disciplines experience their own unique filters on the world. However, every programmer takes shortcuts, and bugs are only bugs if users find them. So consider the downside. The universe may not have been QA approved for shipping yet…it may not even be a fully functional alpha release…

  14. BittenByBits says:

    Seriously, I think the only reason for this “the universe is a simulation” nonsense is because people who spent too much time coding instead of doing real math or physics (1) have experienced a self-induced delusion where they start thinking everything is really 0’s and 1’s
    (2) want to believe their time hasn’t been wasted learning arbitrary rules, and that they are really onto something much more profound, thus wasting everyone else’s time with “serious” speculations which are amusing only when turned into science fiction by a talented author, and which were always tongue-in-cheek in the first place, except possibly in the case of Philip K. Dick, who was not only an amazingly creative writer but battled very real paranoia and schizophrenia.

    Exhibit A: Wolfram.

  15. Another Anon says:

    ” why very smart people are involved in such a dumb argument”

    Physics has always been influenced by the technological advances of the day. As an example, steam power influencing the development of thermodynamics.

  16. Tammie Lee Haynes says:

    Dear Dr Woit

    In re “the Universe is a simulation”
    Have you ever heard of anything more creationist, in the literal sense?

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