Michio Kaku: No Computer Can Simulate the Universe Except the Universe Itself | AI Podcast Clips
00:00:00.000 | - The strings kind of inspire a view,
00:00:05.000 | as did atoms and particles and quarks,
00:00:08.760 | but especially strings inspire a view of the universe
00:00:12.360 | as a kind of information processing system,
00:00:14.640 | as a computer of sorts.
00:00:17.200 | Do you see the universe in this way?
00:00:19.320 | - No.
00:00:20.600 | Some people think, in fact, the whole universe
00:00:23.080 | is a computer of some sort.
00:00:25.480 | And they believe that perhaps everything,
00:00:28.240 | therefore, is a simulation.
00:00:29.680 | - Yes.
00:00:30.680 | - I don't think so.
00:00:32.000 | I don't think that there is a super video game
00:00:34.960 | where we are nothing but puppets dancing on the screen
00:00:38.320 | and somebody hit the play button
00:00:40.120 | and here we are talking about simulations.
00:00:43.240 | No, even Newtonian mechanics says that the weather,
00:00:48.240 | the simple weather, is so complicated
00:00:50.480 | with trillions upon trillions of atoms
00:00:52.960 | that it cannot be simulated in a finite amount of time.
00:00:56.480 | In other words, the smallest object
00:00:59.520 | which can describe the weather and simulate the weather
00:01:04.280 | is the weather itself.
00:01:07.000 | The smallest object that can simulate a human
00:01:10.000 | is the human itself.
00:01:12.600 | And if you had quantum mechanics,
00:01:14.480 | it becomes almost impossible to simulate it
00:01:18.120 | with a conventional computer.
00:01:20.440 | This quantum mechanics deals with all possible universes,
00:01:24.200 | parallel universes, a multiverse of universes.
00:01:28.040 | And so the calculation just spirals out of control.
00:01:32.240 | Now, at so far, there's only one way
00:01:35.360 | where you might be able to argue
00:01:37.920 | that the universe is a simulation.
00:01:39.920 | And this is still being debated by quantum physicists.
00:01:43.040 | It turns out that if you throw the encyclopedia
00:01:46.120 | into a black hole, the information is not lost.
00:01:49.600 | Eventually, it winds up on the surface of the black hole.
00:01:53.200 | Now, the surface of the black hole is finite.
00:01:55.560 | In fact, you can calculate the maximum amount of information
00:01:59.120 | you can store in a black hole.
00:02:01.240 | It's a finite number.
00:02:02.760 | It's a calculable number, believe it or not.
00:02:05.320 | Now, if the universe were made out of black holes,
00:02:07.320 | which is the maximum universe you can conceive of,
00:02:10.600 | each universe, each black hole
00:02:12.760 | has a finite amount of information.
00:02:15.200 | Therefore, ergo, ta-da,
00:02:18.160 | ergo, the total amount of information
00:02:21.640 | in a universe is finite.
00:02:24.480 | This is mind-boggling.
00:02:26.080 | This, I consider mind-boggling,
00:02:28.560 | that all possible universes are countable,
00:02:32.200 | and all possible universes can be summarized in a number,
00:02:35.600 | a number you can write on a sheet of paper,
00:02:37.640 | all possible universes, and it's a finite number.
00:02:40.760 | Now, it's huge.
00:02:42.240 | It's a number beyond human imagination.
00:02:44.240 | It's a number based on what is called a Planck length,
00:02:47.560 | but it's a number.
00:02:49.280 | And so if a computer could ever simulate that number,
00:02:53.160 | then the universe would be a simulation.
00:02:55.680 | - So theoretically,
00:02:57.440 | because the amount of information is finite,
00:03:00.360 | there necessarily must be able to exist a computer.
00:03:05.360 | It's just, from an engineering perspective,
00:03:07.440 | maybe impossible to build.
00:03:09.680 | - Yes, no computer can build a universe
00:03:12.520 | capable of simulating the entire universe,
00:03:14.880 | except the universe itself.
00:03:16.600 | - So that's your intuition,
00:03:18.080 | that our universe is very efficient,
00:03:20.920 | and so there's no shortcuts.
00:03:23.560 | - Right, two reasons why I believe
00:03:25.240 | the universe is not a simulation.
00:03:26.920 | First, the calculational numbers are just incredible.
00:03:30.080 | No finite Turing machine can simulate the universe.
00:03:33.960 | And second, why would any super intelligent being
00:03:37.720 | simulate humans?
00:03:40.000 | If you think about it, most humans are kind of stupid.
00:03:43.600 | I mean, we do all sorts of crazy, stupid things, right?
00:03:46.680 | And we call it art, we call it humor,
00:03:49.520 | we call it human civilization.
00:03:51.920 | So why should an advanced civilization
00:03:54.440 | go through all that effort
00:03:55.960 | just to simulate a Saturday Night Live?
00:03:58.920 | - Well, that's a funny idea,
00:04:01.000 | but it's also, do you think it's possible
00:04:03.000 | that the act of creation cannot anticipate humans?
00:04:07.720 | You simply set the initial conditions
00:04:09.400 | and set a bunch of physical laws,
00:04:11.600 | and just for the fun of it, see what happens.
00:04:14.360 | You launch the thing,
00:04:15.520 | so you're not necessarily simulating everything.
00:04:17.320 | You're not simulating every little bit
00:04:19.640 | in the sense that you could predict what's going to happen,
00:04:23.320 | but you set the initial conditions, set the laws,
00:04:26.600 | and see what kind of fun stuff happens.
00:04:28.800 | - Well, in some sense, that's how life got started.
00:04:32.560 | In the 1950s, Stanley did what is called
00:04:35.760 | the Miller experiment.
00:04:37.400 | He put a bunch of hydrogen gas, methane, toxic gases
00:04:43.440 | with liquid and a spark in a small glass beaker,
00:04:47.960 | and then he just walked away for a few weeks,
00:04:50.720 | came back a few weeks later, and bingo,
00:04:54.080 | out of nothing and chaos came amino acids.
00:04:58.400 | If he had left it there for a few years,
00:05:00.600 | he might've gotten protein, protein molecules for free.
00:05:04.800 | That's probably how life got started, as a accident.
00:05:09.320 | And if he had left it there for perhaps a few million years,
00:05:12.520 | DNA might have formed in that beaker.
00:05:16.400 | And so we think that, yeah, DNA, life,
00:05:19.080 | all that could have been an accident
00:05:21.400 | if you wait long enough.
00:05:24.040 | And remember, our universe is roughly 13.8 billion years old.
00:05:28.160 | That's plenty of time for lots of random things to happen,
00:05:32.480 | including life itself.
00:05:34.680 | - Yeah, we could be just a beautiful little random moment
00:05:42.280 | and there could be an infinite number of those
00:05:46.040 | throughout the history of the universe,
00:05:47.960 | many creatures like us.
00:05:50.320 | We perhaps are not the epitome
00:05:51.840 | of what the universe was created for.
00:05:53.640 | - Thank God.
00:05:54.480 | (both laughing)
00:05:55.520 | Let's hope not.
00:05:56.360 | Just look around.
00:05:58.080 | - Yeah.
00:05:59.280 | - Look to your left, look to your right.
00:06:01.280 | (both laughing)
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