We may be alone in the universe

In the first episode of Bold Conjectures podcast, I talk to Dr Anders Sandberg who is a Senior Research Fellow at Future of Humanity Institute, Oxford University. His academic collaborators include nanotechnology pioneer Eric Dexler and the philosopher Nick Bostrom.

The audio quality isn’t perfect in this one as this is my first podcast. It should get better from here 🙂

What we talk about

  • 1:42 – How to predict the future using history and science-fiction
  • 13:00 – Why talking about probabilities is tricky
  • 17:45 – How to make people care about very distant future
  • 21:10 – Existential risks for humanity
  • 26:45 – Why we may be alone in the observable universe
  • 31:35 – Why the emergence of life is a rare phenomenon
  • 32:25 – What evolutionary transitions need to happen for intelligent life to emerge
  • 35:35 – Do observers evolve first or do the stars burn out first?
  • 40:00 – Humans arrived relatively late in Earth’s history
  • 41:10 – Prediction #1: There’s no life on red dwarf stars
  • 45:25 – Prediction #2: If we find life on Mars, it’ll share a common descendent with life on Earth
  • 47:20 – Why does the Future of Humanity Institute care about alien life?
  • 48:15 – How long does the intelligent life last?
  • 50:57 – Maybe we’re the first intelligent life in the universe?
  • 56:07 – What should we do if we’re the only ones in the universe?
  • 57:00 – Humans matter because we may be alone

Papers by Dr Anders Sandberg mentioned in the episode

Notes and key insights

1/ For my inaugural podcast episode, I interviewed @anderssandberg who is a senior research fellow at the Future of Humanity Institute at Oxford University.

I highly recommend listening to the entire episode. It’s full of gems and insights. But if you want key ideas, here are my notes.

How to model the future

2/ Both history and science fiction shows us how the world can be dramatically different than what it is today.

3/ But exponential curves (like Moore’s law) make it hard to predict the future because early on they look like linear curves.

4/ While you can still model laws like Moore’s laws, predicting when a world leader will launch a nuclear attack is impossible.

5/ Hence, predicting the long-term future of humanity is intractable and that is why you must resort to using probabilities for describing the likelihood of different types of futures that can unfold.

6/ Laws of physics are the most reliable factors in predictions (like nothing could go faster than light).

These laws place an upper bound on predictions like how fast can an intelligent species spread across the entire universe.

7/ When it comes to predicting the future, Hollywood movies distort our perception because they’re made for excitement, not for exploring the truth.

8/ What is the consensus among philosophers about the future of humanity? Existential risks are a top priority in the community.

Why we may be alone in the observable universe

9/ Fermi paradox: where are all the intelligent species in-universe? We don’t see them.

10/ Drake equation multiplies various factors together for estimating how many intelligent species should we find in our galaxy.

11/ For the Drake equation, we have a good idea about astrophysical factors (like planet formation) but for other factors like life formation, we have no idea about its probabilities.

12/ Traditional approaches of Drake equation input a number, but we should put in ranges of numbers.

Hence, the output of the Drake equation should be a probability distribution, not one number.

13/ When you put reasonable numbers for the Drake equation, you get a wide range of possibilities with a high chance that we may be the only intelligent species around.

14/ If you want to avoid the conclusion that we may be alone, you have to claim to know the probability of life formation and the probability of emergence of intelligence with rather high precision (which we don’t).

15/ Ultimately, the rareness of intelligent life comes from high uncertainty about how likely life is

Why the emergence of intelligent life is a rare phenomenon

16/ Life on Earth could indicate life is common OR that Earth was incredibly lucky.

However, even if life is common in the universe, it could be the case that most life doesn’t go beyond single celled organisms.

17/ Many evolutionary transitions need to happen before intelligent life could emerge.

This is what @anderssandberg and his colleagues explore in their latest paper.

18/ Evolutionary transitions that need to happen before we get intelligent life: abiogenesis, prokaryotes -> eukaryotes, sexual reproduction, multi-cellularity, and then culture/intelligence.

19/ Some steps are easy (e.g. multi-cellularity is not a difficult step in evolution because it evolved multiple times independently)

20/ However, some steps are hard. Eukaryotes evolved just once because have to go right for it to happen.

21/ Assuming these evolutionary transitions take time, what are the chances that observers emerge before a star burns out?

22/ To answer it, you have to take observer selection effects into consideration.

That is, even if this probability is low, on lucky planets like Earth, you will find observers who conclude life emerged early on.

23/ LINCHPIN OF THE PAPER -> Harder the steps, more evenly you find the steps to be distributed.

And we find multiple steps in our evolutionary history pretty evenly distributed, which suggests each of the steps is highly improbable.

24/ Because life took a billion years to emerge on Earth and intelligence took 4 billion years, while the life span of our Sun is 10 billion years, we should expect the probability of abiogenesis or transition to intelligence to be really hard, and when you combine multiple hard steps, chances of intelligence life emerging anywhere in the universe becomes minuscule.

25/ History of Earth is not good evidence of intelligent life being common in the universe but works as evidence as it being rare.

26/ If intelligent life was easy, we should expect it to emerge very early in Earth’s history

27/ If intelligent life showed up early in Universe’s history, we should imagine our galaxy to be full of such life

Prediction #1: There’s no life on red dwarf stars

28/ Given red dwarf stars are more in number and exist for much longer, why do we find ourselves around a star with a lifespan of 10 billion years and not around a red dwarf star that will keep on shining for trillions of years?

29/ The theory predicts that the fact we don’t find ourselves around red dwarf stars suggests that the conditions around them are not conducive hence we shouldn’t find any life on such stellar systems.

Prediction #2: If we find life on Mars, it’ll share a common descendent with life on Earth

30/ Solar system shared a lot of material in the early period, so it is not unlikely that we may find life on other planets.

So, discovering a different type of life on Mars will suggest the emergence of life is fairly easy but not finding it or finding it similar to Earth’s will suggest that it is pretty hard to kickstart abiogenesis.

Once it emerges, how long does an intelligent life last?

31/ Lower bound: in several decades of splitting the atom, civilizations destroy themselves.

However, if you spread in the space, your existence becomes robust. You’re harder to destroy.

32/ Even at a speed slower than the speed of light, we can spread in the galaxy within a few tens of millions of years.

This again suggests that an empty galaxy is very strong evidence of the rarity of intelligent life

Maybe we’re the first intelligent life in the universe?

33/ It could be a case where intelligent life has just begun in the universe and will spread out across the universe in trillions of years.

34/ Laws of physics allow intelligence to do rearrangement of enormous scales of matter (like galaxies)

We should look at such rearrangements of matter in the universe as evidence of life (technosignatures) but so far we haven’t found any (there are some unresolved mysteries though – see Tabby’s star)

35/ We could look for Dyson spheres too, which are structures that harness the energy of a sun

But we haven’t found any Dyson spheres so far. Maybe we’re early and maybe we get to build a Dyson sphere.

What should we do if we’re the only ones in the universe?

36/ We’re self-replicators capable of building technology, which can overshadow normal physical processes.

37/ So the most important thing is to -> take the future seriously as we’re unique, just arrived on the scene recently but may have a future that spans trillions of years.

38/ We can do several things to ensure we have a future:

  • We can start building tools and institutions that are better than what came before.
  • We can work on reducing (existential or progress-halting) risks that are foreseeable
  • We can work on uncovering risks that we don’t know much about yet

39/ Humans matter because we may be alone

If someone describes universe, they better include us in the description because otherwise description will be incomplete

Because of this, humans have intrinsic value.

Notes by listeners

Have an opinion on this essay? You can send your feedback on email to me.