Robin Hanson on Grabby Aliens, Emulated Humans, Great Filters, and the Elephant in the Brain

George Mason University economics professor Robin Hanson is one of the most original and prolific thinkers I know of. He is a pioneer in prediction markets, invented the concept of the Great Filter as an explanation of the observed rarity of intelligent life in the universe, and has demonstrated just how far you can get exploring matters such as a future dominated by computer emulations of human brains, hidden motivations of human behaviour, and alien civilisations that expand and prevent development of competitors within their territory by applying the principles of classical economics and rigorously following the data wherever they lead.

You’d expect a four hour conversation with Robin Hanson to be a treat, and this wide-ranging discussion with Lex Fridman does not disappoint. Here is a table of contents of topics and times in the video where they are discussed.

0:00:00 — Introduction
0:01:52 — Grabby aliens
0:39:36 — War and competition
0:45:10 — Global government
0:58:01 — Humanity’s future
1:08:02 — Hello aliens
1:35:06 — UFO sightings
1:59:43 — Conspiracy theories
2:08:01 — Elephant in the brain
2:21:32 — Medicine
2:34:01 — Institutions
3:00:54 — Physics
3:05:46 — Artificial intelligence
3:23:35 — Economics
3:26:56 — Political science
3:32:45 — Advice for young people
3:41:36 — Darkest moments
3:44:37 — Love and loss
3:53:59 — Immortality
3:57:56 — Simulation hypothesis
4:08:13 — Meaning of life


Thank you for sharing. Robin Hanson is a super smart individual with the ability to clearly formulate iconoclastic ideas

Had a chance to listen to him on aliens on the Future Strategist podcast about 10 months ago. That was my intro to “grabby” aliens but there is more on the site that John linked to in the OP.


There is an extensive discussion starting at 1:35:06 in this video about UFO sightings and the rather chilling possibility that they might be “panspermia siblings” from another star in the stellar nursery from which the Sun formed who developed a spacefaring technological civilisation millions of years ago, decided not to become grabby themselves, and consider part of their mission to ensure no other civilisation nearby becomes grabby and wrecks the neighbourhood.

Might their appearance just around the time humans obtained access to nuclear energy and space travel (the V2 flew above the Kármán line if launched on a steep trajectory) and the subsequent “false dawn” of space travel after the Moon landing be linked? Could their more apparent recent activity have something to do with the renaissance of space travel exemplified by SpaceX’s Starship ambitions?

Recall that in his book The Invisible College, Jacques Vallée suggested that UFOs are a “control system” by which “the means through which man’s concepts are being rearranged.”


Lex Fridman is not at his best in this interview. Heard him do a lot better with other guests and it’s such a shame because Hanson is very good and he just has to let him speak. But Fridman takes himself so seriously that he feels compelled to launch into too many tangents that often end up being very shallow. I didn’t finish the podcast yet because Lex really gets on my nerves with his endless adulation mixed with sophomoric “what if” interruptions.

The “panspermia” idea is very compelling in a mechanistic sense. In the universe of possibilities, biologically compatible aliens with a common heritage of sorts sounds a lot better than technologically advanced species with no biological overlap with ours.

It could make the difference between the care and outright affection we hold for e.g. bonobos, compared to the indifferent attitude bordering on intentionally genocidal we harbor towards insects.

I am not persuaded by the so-called UFO phenomena as a harbinger of advanced civilizations, etc. The notion that alien UFOs are here to “check on us” or “hold us back” or things like that seems extremely self centered and unlikely. One would have to believe that “they” are here to “hold us back” because if left unchecked “we might destroy the universe”?

And this is always around the corner in the way in which our civilization’s assumed preeminence is both imminent and terrible at scale. Sorry, I think we are projecting too much attention inwards. I am much more aligned to the simulation hypothesis which, for me, better fixes the apparent incongruities of us being all alone in the known universe.


Lex Fridman may not be the best interviewer, but he’s what we’ve got. Nobody else I know of is doing super-long-form, deep-dive interviews with such a wide variety of interesting guests, and he clearly spends a lot of time researching their work and writings and preparing topics to discuss. I’m glad he’s doing it.


I really enjoyed this interview. I was not familiar with Hanson or his “grabby aliens” theory, but he makes some very compelling, well-developed arguments. I look forward to reading his book, The Age of Em.


Got to agree with that. Something which is increasingly grabbing my attention is the emptiness of the universe. When we probe the atom, we find it is mostly empty space. When we probe the cosmos, we find it is mostly empty space. When we talk about the Expanding Universe, we mean that the amount of empty space is increasing. We are a long way from anything else in this galaxy, and impossibly long ways from any other galaxy. A guardian of the universe could feel quite comfortable about leaving us alone and forgetting about us. We are not going to destroy the universe!


I think there are several other options.

Joe Rogan comes to mind, especially given that Lex (I think) is an avowed disciple, from the BJJ to the long interview style. Rogan combines at least three type of topics: MMA, comedians (or “comics” as he insists they should be properly called) and an eclectic mix of thinkers, researchers, politicians, and otherwise interesting people who write or publicly express ideas. It’s the third category that appeals the most for me in his production and he is a really good interviewer. Always well prepared and approaching the subject with humility and the ability to create space for the guest to expand on his or her ideas.

Fridman has much stronger academic credentials, with credible claims to computer science and AI in particular as it relates to self-driving technology. I don’t dislike his style, it just feels in the early stages yet and I think he is still developing as an interviewer. He is in 300s, so when compared to the nearly 2000 shows Rogan has or 500+ for Tim Ferris, he will get a lot better.

Another pioneer of the long form with a very wide range of guests is Tim Ferriss. He is about the same age as Lex, and you can tell from their interviews they both share a sense of longing for starting a family. Ferriss has a well developed process as well as super interesting guests in his “catalog”.

I will offer two more suggestions, albeit their shows are in the 1-2 hour range: Russ Roberts EconTalk and Tyler Cowen. Personally, I prefer Russ Roberts, although his preference for certain repeat guests is somewhat limiting in the long run. He does have a big back catalog to pick from and most shows remain relevant over time. A recent guest you might find interesting is Marc Andreessen whom he interviewed mid-May. Like Ferriss, all his shows come with a full transcript and comment section. Roberts had Robin Hanson on 4 times in his show, between 2007 and 2011

As an interviewer, Conversations with Tyler, Cowen sometimes comes across to me as somewhat distant and unable to connect on a personal level with his guests. He has good guests and good questions. Piketty is a recent guest and one of my personal favorites is a show he did with Philip E. Tetlock on forecasting accuracy.

We live in an amazing time of abundance of extremely high quality information that is freely accessible and attracts excellent communities that amplify the value further. For me, Scanalyst has been serving this purpose as well and I am grateful to you John for generously making it available.


Thanks for these recommendations. Gee, how do you find the time?? I am retired and can’t come close.


Lol … long walks and no TV?

After the 2020 elections I went cold turkey on my NPR listening. I feel a lot happier and the net was freeing up time for other things. Can’t say I miss the pledge drives either… :wink:


NPR is quite good at biasing every bit of their reportage, particularly in what they report and what they don’t. E.g., lots of warm ‘human interest’ stories about the hardships of illegal immigrants accompanied by snark about those who object because they are hurt economically by their presence. They maintain a semi-plausible deniability - for those who are progressive and want to deny their blatant ‘wokeness’. I listen rarely, as I find it infuriating.

I do watch lots of the videos posted on Scanalyst on my exercise machine while I exercise one hour every afternoon, 7 days a week. I still don’t have enough time for long interviews… Lol from here, too.


This idea might warrant its own thread at some point, but for the moment I’ll submit something I learned recently, but which may already be familiar to you. Namely, the phenomenon of quantum fluctuation. My understanding of it is that particle-anti-particle pairs are perpetually flashing into existence at random points for a brief moment before immediately annihilating each other. This is occurring everywhere all the time. So according to quantum field theory, it would appear there is no such thing as truly “empty” space.


Yes, some people are trying to use that hypothesis (not sure if there is any experimental evidence for it) as an explanation for the formation of the Universe. Supposedly, the entire mass of the endless Universe just popped into existence. But wait! It gets worse!

We have a Universe of matter – not anti-matter. What happened? After all, matter & anti-matter are supposed to annihilate each other leaving nothing behnd. The extra hypothesis is that there is a slight imbalance (why?) and something like one in 30,000,000,000 particles of matter survives. So it was not just the entire mass of an uncountable number of galaxies which suddenly popped into existence – it was 30 Billion times the entire mass of the Universe.

This is the point at which my spidey sense starts to tingle, and I am deafened by the sound of angels in clogs dancing upon the head of a very small pin. Quantum theory is like Newtonian gravity – it makes some very good & useful predictions, but that does not mean it is right.


But neither mass nor energy are conserved, but their sum: mass-energy. Gravitational potential energy has a negative value (this is easy to understand if you think that lowering a rock under gravity allows you to extract positive energy from a generator attached to the rope, and since energy is conserved this is balanced by the reduction in the negative gravitational potential energy of the rock).

Well, it turns out that in a universe that is topologically flat (which our universe is, to the best precision we can measure it), the negative gravitational potential energy of all of its contents precisely balances the positive mass-energy of all of its contents, so its total energy content is—zero. Thus the creation of such a universe ex nihilo by a quantum fluctuation or some other mechanism does not violate conservation of energy since the total energy was zero both before and after the creation event.

However, unlike Newtonian gravity, which makes incorrect predictions for cases where objects move rapidly and/or in the vicinity of strong gravitational fields (for example, the orbit of Mercury or starlight passing near the Sun), quantum mechanics has, so far, agreed completely with every experimental test to which it has been subjected, including those for phenomena it predicted which had never before been observed. No theory is ever “right”—it is only as good to the extent its predictions agree with observation and experiment and, so far, no experiment has falsified quantum theory.


This is not just a curiosity of theory, but an aspect of the real world. The Lamb shift in the spectrum of the hydrogen atom is a direct consequence of electrons in different orbitals interacting with virtual particles due to vacuum energy fluctuation.

Vacuum energy fluctuations show one of the most stark conflicts between quantum mechanics and gravitation (general relativity). Although the creation and annihilation of virtual particles from the vacuum has an average net energy of zero, since gravitation is always attractive the particles should generate gravity and a straightforward calculation of their density indicates it should be at least 60 orders of magnitude greater than what is observed from the properties of the universe. This is called the cosmological constant problem and no persuasive solution to it is known.


Or, as they say in the trade – Observation contradicts the theory; back to the drawing board on the theory. The human race knows a lot, but we do not have all the answers.


To @Gavin’s point, is it not possible that a new theory might come along capable of explaining not only the Lamb shift but other phenomena while avoiding the cosmological constant problem you mention? We don’t know what such a theory might look like because it hasn’t been formulated yet, and it never will be formulated unless we keep an open mind to revising what we think we understand. Has not quantum mechanics undergone many changes in its history?

Some years ago we might have mocked Aristotle for not believing in a vacuum. Now it would appear Aristotle has been vindicated.

Anyway, quantum fluctuations seem to be the best explanation we have (at present) for some phenomena, and, apparently, the fluctuations have been directly observed. But to explain the origin of the universe with these fluctuations seems like a massive stretch.


The only effective part ∑Ω>0 â Ωâ Ω† of the operator that extracts the variance of the field in Eq. 4 indicates that vacuum fluctuations correspond to photons, which spontaneously arise and vanish in the ground state Φ0.

I am not a quantum physicist – but that sounds rather like 'We have made statistical observations on an imperfect vacuum and this is the theory with which we interpret the results". Maybe there are other theories that would equally explain those observations, rather in the way that Newtonian gravity and Einsteinian space-time warping can both explain the movements of the Moon quite satisfactorily? It is not direct observation.


What if 13.8Gyr is off by an order of magnitude?

The LambdaCDM model has been called into question by the JWST among other things (such as the Hubble Tension).


I downloaded the code from github and changed the hardcoded 13.787Gyr to be a command line parameter of Maybe someone more familiar with the paper can do a sanity check on the output.

Here’s the plot generated by the first README example when I set the current age of the universe to 100Gyr:
To generate figure 13: time python3 --D 3 --n 1.5,3,6,12 --N 1e8 --sc 1.0,0.75,0.5,0.25 --L 1 --s 1 --seed 0 --empty 100 au=100

Here’s the plot when I let it default to 13.787Gyr: