Here’s some video of me spouting about Deep Questions
In January 2014, I attended an FQXi conference on Vieques island in Puerto Rico. While there, Robert Lawrence Kuhn interviewed me for his TV program Closer to Truth, which deals with science and religion and philosophy and you get the idea. Alas, my interview was at the very end of the conference, and we lost track of the time—so unbeknownst to me, a plane full of theorists was literally sitting on the runway waiting for me to finish philosophizing! This was the second time Kuhn interviewed me for his show; the first time was on a cruise ship near Norway in 2011. (Thankless hero that I am, there’s nowhere I won’t travel for the sake of truth.)
Anyway, after a two-year wait, the videos from Puerto Rico are finally available online. While my vignettes cover what, for most readers of this blog, will be very basic stuff, I’m sort of happy with how they turned out: I still stutter and rock back and forth, but not as much as usual. For your viewing convenience, here are the new videos:
- The black hole information paradox, firewalls, and Harlow-Hayden argument (6 minutes)
- Physics and free will (8 minutes 24 seconds)
- Which entities are conscious? (6 minutes 3 seconds)
- Quantum mechanics, the predictability of nature, the Bell inequality, and Einstein-certified randomness (5 minutes 12 seconds)
- What’s the value of philosophy, and can it make progress? (3 minutes 42 seconds)
- Newcomb’s Paradox (4 minutes 13 seconds)
- Gödel’s Theorem and the definiteness of mathematical truth (8 minutes 20 seconds)
I had one other vignette, about why the universe exists, but they seem to have cut that one. Alas, if I knew why the universe existed in January 2014, I can’t remember any more.
One embarrassing goof: I referred to the inventor of Newcomb’s Paradox as “Simon Newcomb.” Actually it was William Newcomb: a distant relative of Simon Newcomb, the 19th-century astronomer who measured the speed of light.
At their website, you can also see my older 2011 videos, and videos from others who might be known to readers of this blog, like Marvin Minsky, Roger Penrose, Rebecca Newberger Goldstein, David Chalmers, Sean Carroll, Max Tegmark, David Deutsch, Raphael Bousso, Freeman Dyson, Nick Bostrom, Ray Kurzweil, Rodney Brooks, Stephen Wolfram, Greg Chaitin, Garrett Lisi, Seth Lloyd, Lenny Susskind, Lee Smolin, Steven Weinberg, Wojciech Zurek, Fotini Markopoulou, Juan Maldacena, Don Page, and David Albert. (No, I haven’t yet watched most of these, but now that I linked to them, maybe I will!)
Thanks very much to Robert Lawrence Kuhn and Closer to Truth (and my previous self, I guess?) for providing Shtetl-Optimized content so I don’t have to.
Update: Andrew Critch of CFAR asked me to post the following announcement.
We’re seeking a full time salesperson for the Center for Applied Rationality in Berkeley, California. We’ve streamlined operations to handle large volume in workshop admissions, and now we need that volume to pour in. Your role would be to fill our workshops, events, and alumni community with people. Last year we had 167 total new alumni. This year we want 120 per month. Click here to find out more.
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Comment #1 February 4th, 2016 at 9:08 pm
These are great!
Comment #2 February 4th, 2016 at 9:13 pm
John: After reading your comment, I can go to sleep happy.
Comment #3 February 5th, 2016 at 12:00 am
It is good to hear that there is a center for Applied Rationality; we can all use more of that. Somewhat of a surprise to find it in Berkeley, where being rational might be against city ordinance. That would be a tough place to teach logic — perhaps legislation has redefined OR to be XOR until the next council meeting.
Comment #4 February 5th, 2016 at 12:39 am
That’s just it: ‘spouting’. The trouble with ‘spouting’ is that it rarely prodcues any real insight 😉
Great philosophical ideas drive the world forward. Unfortunately, great philosophical ideas are exceedingly rare, and the vast majority of what passes for ‘philosophy’ is mere babble, which tends to obfusticate rather than illuminate.
I think people such as yourself (Scott) are worth listening to, because you’re an expert in the relevant areas! But the proverbial ‘man on the street’ is unlikely to be saying anything much of value.
The trouble with philosophy is that there’s no easy way of resolving disputes in a manner that a majority can agree on, so people can just go on spouting nonsense with no ‘reality checks’ or real feedback, meaning it all becomes more like word games or personal opinions.
The really great ideas in history are all very simple and clear to state. I think most people who try to philosophize tend to massively overcomplicate – people veer off into flowery language and really strange and complicated notions in order to sound clever and cover up their lack of understanding. It’s nearly always a big mistake to ignore the principle of Occam’s razor;The simplest explanation is almost always the best.
Would have liked to hear your views on the existence of the universe question. I think if the quantifier ‘existence’ is something binary and absolute (True/False) then the question is unanswerable. The only way there could be an answer to this one is if ‘existence’ is a matter of degree; bring in the notion of ‘possible worlds’ and introduce some sort of continuous measure about how ‘real’ the possible worlds are (the ‘reality fluid’ model).
Comment #5 February 5th, 2016 at 2:22 am
I’ll second John Preskill and say these talks are great, and then follow up with a question.
In the talk on the nature of consciousness, I am not quite sure what you mean when you say “consciousness ought to have something to do with irreversibility. ” What does it mean for an entity to be sensitive to “small fluctuations?” Can you give an example of any physical system that is sensitive to “small fluctuations” and perhaps explain the mechanism of this sensitivity?
Note that you are forgiven for not coming up with a irrefutable definition of consciousness in a 6 minute interview, but I suspect you would be able to elaborate on the things you said.
Comment #6 February 5th, 2016 at 5:53 am
We have met the Boltzmann brains and we are them.
I like your conscious entities answer – ultimately it just seems to give the right answer.
Comment #7 February 5th, 2016 at 7:05 am
Raoul #3: LOL! Having lived in Berkeley for four years, I can attest that the Center for Applied Rationality should be there for perhaps the same reasons why Doctors Without Borders should be in Sierra Leone. 🙂
Incidentally, there was a major recent New York Times Magazine piece about CFAR, featuring my good friend Julia Galef. That should give you a better idea of what they do (it gave me a better idea).
Comment #8 February 5th, 2016 at 7:12 am
Chris Blake #5: I developed those thoughts in more detail in my Could a Quantum Computer Have Subjective Experience? talk, and even more (though with a focus on predictability rather than consciousness) in my Ghost in the Quantum Turing Machine essay.
Comment #9 February 5th, 2016 at 10:50 am
On the subject of consciousness and QM interpretation.
If we assume that the many-worlds interpretation of QM is true, then isn’t it the case that a sort of individual anthropic principle would apply:
I.e. the subjective life I am experiencing is always gonna be the one that maximizes my longevity.
Among all the alternative copies of myself, by definition, the ones which avoid death are the ones that will carry on my consciousness.
So, people around me will seem to die according to the average life expectancy statistics, but I will probably end up living pretty old?
(I recently had some serious health issue and the doctors have been telling me that I’ve been incredibly lucky that the problem was caught early by chance… which got me thinking, haha)
Comment #10 February 5th, 2016 at 1:28 pm
mjgeddes #4:
Would have liked to hear your views on the existence of the universe question.
If I remember correctly, what I did in that vignette was to argue that, if we want to make mental peace with the “Why does the universe exist?” question, the key thing we need to do is forget about the universe for a while, and just focus on the meaning of the word “why.” I.e., when we ask a why-question, what kind of answer are we looking for, what kind of answer would make us happy? (Cf. my exchange with Lily.)
Notice, in particular, that there are hundreds of other why-questions, not nearly as prestigious as the universe one, yet that seem just as vertiginously unanswerable. E.g., why is 5 a prime number? Why does “cat” have 3 letters?
Now, the best account of “why”—and of explanation and causality—that I know about is the interventionist account, as developed for example in Judea Pearl’s work. In that account, to ask “Why is X true?” is simply to ask: “What could we have changed in order to make X false?” I.e., in the causal network of reality, what are the levers that turn X on or off?
This question can sometimes make sense even in pure math. For example: “Why is this theorem true?” “It’s true only because we’re working over the complex numbers. The analogous statement about real numbers is false.” A perfectly good interventionist answer.
On the other hand, in the case of “Why is 5 prime?,” all the levers you could pull to make 5 composite involve significantly more advanced machinery than is needed to pose the question in the first place. E.g., “5 is prime because we’re working over the ring of integers. Over other rings it admits nontrivial factorizations.” Not really an explanation that would satisfy a four-year-old (or me, for that matter). 🙂
And then we come to the question of why anything exists. For an interventionist, this translates into: what causal lever could have been pulled in order to make nothing exist? Well, whatever lever it was, presumably the lever itself was something, and so you see the problem right there. 🙂
Admittedly, suppose there were a giant red button, somewhere within the universe, that when pushed would cause the entire universe (including the button itself) to blink out of existence. In that case, we could say: the reason why the universe continues to exist is that no one has pushed the button yet. But even then, that still wouldn’t explain why the universe had existed.
Comment #11 February 5th, 2016 at 1:30 pm
Fred, the originator of Many Worlds (at the time called Relative State) formulation of quantum mechanics had the exact same belief.
Read about the suicide of Hugh Everett’s daughter Elizabeth.
Comment #12 February 5th, 2016 at 1:31 pm
https://en.wikipedia.org/wiki/Quantum_suicide_and_immortality
Comment #13 February 5th, 2016 at 3:54 pm
Bobby #11
Nice.
So this suggests that the destiny of all of us is to eventually be hailed as medical miracles of incredible longevity and luck.
We are also all bound to live in worlds where humanity somehow manages to dodge various destruction scenarios (asteroid impact, nuclear annihilation, rampant AI, Trump becoming president, etc).
Of course we will all experience this in our very own little private sample distribution of all the possible worlds…
Guys, remember this when you’ll be 120 years old!
Comment #14 February 5th, 2016 at 4:50 pm
If you’re at the end of your (very long) life, with a terminal disease, would you be willing to try the quantum suicide experiment?
You won’t be able to communicate the results, but at least you will know whether or not MW is true…
Comment #15 February 5th, 2016 at 5:32 pm
#fred #14
Actually won’t you never know if it is true or false?
The same situation we are in now without trying the experiment.
Comment #16 February 5th, 2016 at 6:14 pm
:-O Damn you’re good Scott! Insightful.
Well I think you’re right, without some causal mechanism you can point to that can fix something to be different, there’s no way to get a handle on the universe exists question.
So we need a ‘multiverse of possible worlds’ to exist, and then we need to point to some causal feature that could be different in the space of possible worlds that would prevent our particular region from existing? That still wouldn’t explain the existence of multiverse in the first though.
Excellent answer to the mathematical question in the video, I agree with that.
But I think we need to consider ‘existence’ not as an absolute Boolean value (Existence/Non-Existence), but more like a continuous shading (turning the brightness of a light up and down for example).
So while I agree with you that at least some mathematical truths ‘exist’ objectively (these seem like a plausible ‘ground-state’ for existence) I think that math has a ‘weaker’ sort of existence than physics. If you imagine mathematics as the basic ‘reality fluid’, then physics is the ‘ice’ – it’s existence is more ‘solid’ than math. But the most ‘solid’ form of existence, I think, resides in the coherent perceptions and explanations of a conscious mind.
So we can define 3 main ‘states’ of existence; in order of increasing ‘solidity’:
Mathematics >>>> Physics >>>> Minds
I think the correct measure of how strongly something exists is COHERENCE. Coherence seems to be the only measure I can think of that can be applied across all three layers of existence above. If we imagine ‘pulling out’ coherence, then ‘existence’ is lost for all three! So perhaps we can say that COHERENCE is the reason why the universe exists.
Comment #17 February 5th, 2016 at 7:24 pm
@fred #9 #14
Actually, you will never die, because there is always one more branch in the m.w.i. where you are kept alive.
A bit creepy, but good luck to you …
Comment #18 February 6th, 2016 at 4:40 am
Science can find an answer to materialistic nature of universe because this option can be explored & tested experimentally.
While philosophy explores an answer to conscious nature i.e. meaning & purpose of evolution of universe. This can not be detected by any method of science or physical laws of nature.
Real progress can take place only if science & philosophy works together keeping respect for each other and exploring the hidden truth of universe.
Philosophy drives the concept of independent existence of consciousness(responsible for behavioural traits & basic instincts of life) which should be acceptable to science.
Science drives the concept of physical laws of nature and existence of an eternal matter/energy stuff which should be acceptable to philosophy.
Thus, if acceptable to both, science & philosophy should believe in co-existence of two eternal realities in nature i.e. consciousness & matter/energy stuff.
Comment #19 February 6th, 2016 at 8:30 am
Ajay #18: OK, but the tricky part is that the two realms presumably need to interface with each other somehow—and it’s in speculations about the interface that philosophy has traditionally “stepped on science’s toes”! (Descartes, for example, thought that the soul influenced the body via the pineal gland, an idea already ridiculed by his student Princess Elisabeth.)
Comment #20 February 6th, 2016 at 6:04 pm
Fred, Bobby — a major worry with quantum immortality is that after 100 years or so the majority of the copies of you that are still alive might not want to be alive. They might be demented, frail, in horrible pain, or on the very verge of consciousness. You might find yourself to be eternally in a hospital bed, just wishing you could only ever die. Quantum immortality could in fact be a horrifying, hell-like possibility.
Comment #21 February 6th, 2016 at 6:19 pm
Wolfgang
Its more than a bit creepy, it ought to be truly terrifying because the future includes a multitude of arbitrarily bad, conscious-but-not-quite-dead-yet possibilities each of which will experienced by a future self in virtual solitude (everyone else you knew having long since died). And of course, there would no escape – suicide being no use (as in the movie Ground Hogs Day ;). Fortunately, I think the many world’s fate is either highly unlikely or that my path thus far has been extraordinarily lucky (much luckier than required by many world’s). If its the latter, my luck should be running out in a substantial subset of my futures 😉
Comment #22 February 6th, 2016 at 8:20 pm
I’m not sure that quantum suicide would extend to cases of “natural death”, compared to the usual thought experiment, where death is or isn’t caused by the outcome of a measurement of a quantum state. Reason being, when it comes to dying of old age, it may well be that *none* of the possible universes have a living me.
Comment #23 February 6th, 2016 at 10:34 pm
Well, there is some economy (and comfort!) in supposing that the universe only bothers to fork for quantum thought experiments.
Comment #24 February 7th, 2016 at 3:08 pm
That would be a lot like superdeterminism, wouldn’t it? My thought is (hopefully, but no promises) less silly, that if MWI is true, the only worlds that should exist are ones that could have evolved to their state with some non-zero probability. The thought experiment is designed to ensure this, since the result is based on the outcome of a single quantum measurement. On the other hand, if it turned out that human lifespan could be described a function similar to “every year, we die with a probability of n/130, where n is our age”, then we shouldn’t expect any worlds with people living to 135. (Or maybe worlds that split long ago, so early in their evolution that n/130 wasn’t yet set in stone, have different lifespan function, but we’re now committed to ours, and we shouldn’t expect any branches from our present state to admit something as strange as a 135 year old.)
Comment #25 February 8th, 2016 at 1:16 am
I watched the video with your thoughts on consciousness, interesting, but I don’t really agree with you there.
My belief that ‘coherence’ is correlated with the ‘existence’ measure, strongly supports the Tononi/Koch Integrated Information Theory of consciousness.
Remember, I hypothesized 3 main states of ‘existence’ built from a ground-state of mathematical information, analogous to the Gas/Liquid/Solid distinction, with ‘coherence’ playing the analogous role of ‘temperature’. Increasing information coherence causes ‘phase transitions’ in the mathematical information such that mathematical information can appear to us as matter and consciousness.
Math (Weak coherence information) >> Matter (Medium coherence information) >>> Mind (Strong coherence information)
Consciousness is just ‘highly crystallized’ (highly integrated, high coherence) information in my model. This matches the IIT.
Comment #26 February 11th, 2016 at 2:32 pm
I would kind of like you, Scott, to offer your insight on the QI debate that has been going on in this comment section. I believe you might have some interesting points to add.
Comment #27 February 11th, 2016 at 3:36 pm
khz #26: Sorry I’ve been absent. I have to confess that debates about quantum immortality sometimes give me the temptation to jump off a bridge, so that my consciousness could switch to a different branch of the wavefunction where such debates aren’t happening! 😉
More seriously: it seems to me like insanity to imagine you get to do life-threatening things and simply condition on surviving them, rather than worrying about the survival probability. (Not “insanity” in some figurative sense, just literally: someone who actually tried quantum suicide experiments and survived them would presumably get involuntary psychiatric care, like other attempted suicides.)
Furthermore, this strikes me as a point that we can take as given before we even bring MWI into the discussion. After all, to be taken seriously as an interpretation, the very least MWI needs to do is reproduce the predictions of textbook QM, in all situations where textbook QM applies. And textbook QM says the probability of observing a given outcome is |α|2, where α is the outcome’s amplitude. It doesn’t say the probability is 0 if you’re dead or |α|2/p if you’re alive, where p is your total probability of remaining alive. So if MWI predicted that modified rule, it wouldn’t be a problem for ordinary sanity or rationality; it would just be grounds to reject MWI.
But fortunately for MWI, I don’t see any good argument that MWI does predict the modified rule. Among all the branches of the wavefunction in your causal future, why on earth should probability mass be distributed only among the ones where you happen to exist? Isn’t imagining such a thing a return to solipsism—i.e., the very tendency that MWI was invented to try to fight, by removing yourself and your observations from the center of physics? If we want to be solipsists, then why not just go back to the Copenhagen interpretation?
In short, if you agree that “I should act as if I’m necessarily immortal” is a crazy thing to think pre-MWI, then I submit that MWI doesn’t make it any less crazy!
Finally, I recently read Peter Byrne’s interesting biography of Hugh Everett, where it’s written (page 342):
It is unlikely, however, that Everett subscribed to this [quantum immortality] view, as the only sure thing it guarantees is that the majority of your copies will die, hardly a rational goal.
To clarify, if Everett had indulged in this particular insanity, I’d have no hesitation in saying that Everett was wrong, that his theory is better than that. But contrary to Bobby #11, Everett’s biographer thinks he didn’t indulge in it.
Comment #28 February 11th, 2016 at 7:42 pm
Scott #27, sorry for following up on a bridge-jump-inducing topic, but ISTM you’re sweeping the distinctive feature of QI scenarios under the rug when you appeal to the usual notion of “observing a given outcome”. In this context we’re talking about an observer that only exists in a subset of branches, rather than one “outside” the system that can just assume they’ll be around regardless of which branch they land in.
Eg, the only branches where Schrodinger’s cat observes anything are the “lucky” ones where it survived. So if we assume MWI, right after we toss the coin don’t we *know* that there’s a live version of “the” cat somewhere in the wavefunction? Granted, from our single-branch perspective it only has a 50/50 chance of survival, but from (the necessarily surviving version of) the cat’s perspective it sure seems like the coin is always coming up heads.
It doesn’t look that different from non-QI scenarios involving probabilities of subjective experiences. Before flipping a quantum coin, an MWI’er knows “they” will observe heads *and* tails. So in a certain sense the “probabilities” add up to 2, and to talk about the actual probability of ending up in one branch or the other they’d need to normalize by the number of created/branched copies. (Or substitute with a Sleeping Beauty-type scenario to take MWI out of the mix entirely.) QI is just the case where the “probabilities” add up to something less than 1, and the event in question (having any continued experience whatsoever) has the same “probability” as the normalizing constant.
They’re kind of dual scenarios: Copying is weird because we shift from a perspective where both events are possible to one where they’re mutually exclusive. QI is weird because we shift from a perspective where the events (living/dying) are mutually exclusive to one where they both happen (eg, if Schrodinger’s cat subscribed to MWI, the surviving version would know that another version of it wasn’t so lucky).
Comment #29 February 12th, 2016 at 3:48 am
I didn’t mean to sound judgmental, I just wanted to point out that I would be interested in hearing your opinion 🙂
I don’t think a quantum suicide experiment is the interesting situation here: there are many more interesting and worrying ones. Consider this: let’s say that I contract a terminal illness, with a 90% chance of killing me each day, and a 9% chance of causing increasing pain.
Normally, I would say goodbye to my family members and expect to die after a few days. But with QI, the *subjective* probabilities change, even if the normal rules of QM are left untouched: now there’s a 100% chance of subjectively surviving each day, and a 90% chance of increasing pain. So what should I do? Ordinarily, in a similar kind of situation I would move to a country where euthanasia is legal: but QI seems to make sure that euthanasia will fail, too! Should I, then, sign up for cryonics and hope that the likelihood of dying and being resurrected by a friendly future civilization will ultimately outweigh the likelihood of surviving “normally” (or being resurrected by an unfriendly future civilization)? Actually, that may apply to euthanasia and friendly future superintelligences as well.
Arguably, this kind of immortality follows not just from MWI, but from any theory (be it inflation, string theory, cyclic universe or mathematical universe) that predicts an infinite world and an infinite number of observers. But the idea is so ludicrous that it seems there has to be something wrong with it! That’s why I think it’s important to talk about QI: it has, I think, the potential to be one of the most profound weird things that we’ve learned about life in this universe, and most people have not even heard of it.
It’s interesting to hear that Everett perhaps didn’t believe in it himself: I’ve thought he did. Although I wonder if that’s just speculation from his biographer, who perhaps doesn’t quite understand the idea.