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It's not an eternity because QC is a low-headroom tech which is already pushing its limits. What made computing-at-scale possible wasn't the transistor, it was

It's not an eternity because QC is a low-headroom tech which is already pushing its limits. What made computing-at-scale possible wasn't the transistor, it was the precursor technologies that made transistor manufacturing possible - precise control of semiconductor doping, and precision optical lithography. Without those the transistor would have remained a lab curiosity. QC has no hint of any equivalent breakthrough tech waiting to kick start a revolution. There are plenty of maybe-perhaps technologies like Diamond Defects and Photonics, but packing density and connectivity are always going to be huge problems, in addition to noise and error rate issues. Basically you need high densities to do anything truly useful, but error rates have to go down as packing densities go up - which is stretching optimism a little. Silicon is a very forgiving technology in comparison. As long as your logic levels have a decent headroom over the noise floor, and you allow for switching transients (...the hard part) your circuit will be deterministic and you can keep packing more and more circuitry into smaller and smaller spaces. (Subject to lithography precision.) Of course it's not that simple, but it is basically just extremely complex and sophisticated plumbing of electron flows. Current takes on QC are the opposite. There's a lot more noise than signal, and adding more complexity makes the problem worse in non-linear ways.

lisper 1y ago
I'm sympathetic to this argument, but nearly every technological breakthrough in history has been accompanied by plausible-sounding arguments as to why it should have been impossible. I myself left my career as an AI researcher about 20 years ago because I was convinced the field was moribund and there would be no major breakthroughs in my lifetime. That was about as well-informed a prediction as you could hope to find at the time and it was obviously very wrong. It is in the nature of breakthroughs that they are rare and unpredictable. Nothing you say is wrong. I would bet against QC is 5 years (and even then I would not stake my life savings) but not 75.
- lqstuart 1y ago
  In fairness, the biggest breakthrough in AI has been calling more and more things “AI.” Before LLMs it was content based collaborative filtering.
  - lisper 1y ago
    No, LLMs are a real breakthrough even if they are not by themselves reliable enough to produce a commercially viable application. Before LLMs, no one knew how to even convincingly fake a natural language interaction. I see LLMs as analogous to Rodney Brooks's subsumption architecture. Subsumption by itself was not enough, but it broke the logjam on the then-dominant planner-centric approach, which was doomed to fail. In that respect, subsumption was the precursor to Waymo, and that took less than 40 years. I was once a skeptic, but I now see a pretty clear path to AGI. It won't happen right away, but I'd be a little surprised if we didn't see it within 10 years.
    - seanmcdirmid 1y ago
      I thought Waymo was much more ML than logical rules based subsumption? I’m not sure it’s possible to do more than simple robotics without jumping into ML, I guess maybe if you had high level rules prioritized via subsumption but manipulating complex ML-trained sensors and actuators.
      - lisper 1y ago
        Yes, that's right. The ostensible idea behind subsumption is dead (because it was wrong). But what subsumption did was open up the possibility of putting the AI into the run-time feedback loop rather than the deliberative planning, and that is what all robotic control architectures do today.
    - kibwen 1y ago
      > It won't happen right away, but I'd be a little surprised if we didn't see it within 10 years. Meanwhile, even after the infamous LK-99 fiasco (which gripped this forum almost more than anywhere else) was exposed as an overblown nothingburger, I still had seemingly-intelligent people telling me with all seriousness that the superconductor breakthrough had a 50% chance of happening within the next year. People are absolutely, terminally terrible at estimating the odds of future events that are surrounded by hype.
    - Retric 1y ago
- kibwen 1y ago
  > nearly every technological breakthrough in history has been accompanied by plausible-sounding arguments as to why it should have been impossible Indeed, and at the same the breakthroughs are vastly outnumbered by ideas which had plausible sounding counterarguments which turned out to be correct. Which is to say, the burden of proof is on the people making claims that something implausible-sounding is plausible.
  - lisper 1y ago
    But QC is quite plausible. There is no theoretical constraint that makes it impossible. It really is just an engineering problem at this point.
    - kibwen 1y ago
      But the distinction that we're trying to make here is that people hear "plausible in theory" and think "plausible in practice within the timespan of human civilization", which does not follow. I'm not trying to say anything about whether or not a CRQC will ever be built. I'm also not trying to say that pursuing PQC in the short term is a bad idea. But what I am saying is that the burden of proof remains on the believers to show that the engineering challenges are more than theoretically surmountable.
      - lisper 1y ago
        Yes, of course that is true. When I said that QC is "just an engineering problem" I did not mean to imply that it was straightforward. It's not. It's a Really Really Hard engineering problem with a lot of unknowns. It might turn out to be like fusion, perpetually 10-20 years away. Or it might turn out to be like the blue LED, seemingly impossible until someone figured out how to do it. I think you'd be foolish to bet your life savings on it either way.

lisper 1y ago

I'm sympathetic to this argument, but nearly every technological breakthrough in history has been accompanied by plausible-sounding arguments as to why it should have been impossible. I myself left my career as an AI researcher about 20 years ago because I was convinced the field was moribund and there would be no major breakthroughs in my lifetime. That was about as well-informed a prediction as you could hope to find at the time and it was obviously very wrong. It is in the nature of breakthroughs that they are rare and unpredictable. Nothing you say is wrong. I would bet against QC is 5 years (and even then I would not stake my life savings) but not 75.

lqstuart 1y ago
In fairness, the biggest breakthrough in AI has been calling more and more things “AI.” Before LLMs it was content based collaborative filtering.
- lisper 1y ago
  No, LLMs are a real breakthrough even if they are not by themselves reliable enough to produce a commercially viable application. Before LLMs, no one knew how to even convincingly fake a natural language interaction. I see LLMs as analogous to Rodney Brooks's subsumption architecture. Subsumption by itself was not enough, but it broke the logjam on the then-dominant planner-centric approach, which was doomed to fail. In that respect, subsumption was the precursor to Waymo, and that took less than 40 years. I was once a skeptic, but I now see a pretty clear path to AGI. It won't happen right away, but I'd be a little surprised if we didn't see it within 10 years.
  - seanmcdirmid 1y ago
    I thought Waymo was much more ML than logical rules based subsumption? I’m not sure it’s possible to do more than simple robotics without jumping into ML, I guess maybe if you had high level rules prioritized via subsumption but manipulating complex ML-trained sensors and actuators.
    - lisper 1y ago
      Yes, that's right. The ostensible idea behind subsumption is dead (because it was wrong). But what subsumption did was open up the possibility of putting the AI into the run-time feedback loop rather than the deliberative planning, and that is what all robotic control architectures do today.
  - kibwen 1y ago
    > It won't happen right away, but I'd be a little surprised if we didn't see it within 10 years. Meanwhile, even after the infamous LK-99 fiasco (which gripped this forum almost more than anywhere else) was exposed as an overblown nothingburger, I still had seemingly-intelligent people telling me with all seriousness that the superconductor breakthrough had a 50% chance of happening within the next year. People are absolutely, terminally terrible at estimating the odds of future events that are surrounded by hype.
  - Retric 1y ago
kibwen 1y ago
> nearly every technological breakthrough in history has been accompanied by plausible-sounding arguments as to why it should have been impossible Indeed, and at the same the breakthroughs are vastly outnumbered by ideas which had plausible sounding counterarguments which turned out to be correct. Which is to say, the burden of proof is on the people making claims that something implausible-sounding is plausible.
- lisper 1y ago
  But QC is quite plausible. There is no theoretical constraint that makes it impossible. It really is just an engineering problem at this point.
  - kibwen 1y ago
    But the distinction that we're trying to make here is that people hear "plausible in theory" and think "plausible in practice within the timespan of human civilization", which does not follow. I'm not trying to say anything about whether or not a CRQC will ever be built. I'm also not trying to say that pursuing PQC in the short term is a bad idea. But what I am saying is that the burden of proof remains on the believers to show that the engineering challenges are more than theoretically surmountable.
    - lisper 1y ago
      Yes, of course that is true. When I said that QC is "just an engineering problem" I did not mean to imply that it was straightforward. It's not. It's a Really Really Hard engineering problem with a lot of unknowns. It might turn out to be like fusion, perpetually 10-20 years away. Or it might turn out to be like the blue LED, seemingly impossible until someone figured out how to do it. I think you'd be foolish to bet your life savings on it either way.