
I Hope the Search for Extraterrestrial Life Finds Nothing (2008) [pdf] - jules-jules
https://www.nickbostrom.com/extraterrestrial.pdf
======
ohazi
God I can't stand Nick Bostrom.

I think the great filter is definitely ahead of us, but I'm not so terrified
by the implications of this (or so interested in being a pompous contrarian)
that I'm moved to bury my head in the sand and publicly hope for stupid
things.

I hope we find current or ancient life on Mars, Europa, etc. because that
would be interesting and exciting.

It would bring no more additional existential dread than looking outside at
your fellow idiot humans.

Life is hard, and we're probably all going to die. Get over it. We can still
hope to find interesting things while we're around to enjoy them.

~~~
codezero
I'm not even sure who Nick Bostrom is, but thanks for your comment, it stands
on its own :)

~~~
jules-jules
In case you were serious, Nick Bostrom is a philosopher with a background in
theoretical physics, computational neuroscience, logic, and artificial
intelligence. He is a Professor at Oxford University, where he leads the
Future of Humanity Institute as its founding director.

~~~
codezero
Yep I was, and thanks for doing emotional labor for me, I probably wouldn’t
have bothered googling him :)

------
dhosek
I'm afraid we're looking at a great filter event very soon. We're doing
nothing about global warming, we've demonstrated that the United States has a
significant fraction of its population which values short-term pleasure over
the most basic work to prevent the spread of a pandemic (and we're likely to
see these sorts of things happen more, not less frequently as we continue to
encroach on wildlife habitat). I'm increasingly skeptical of the ability for
civilization to make it into the 21st century.

~~~
jeffreyrogers
I really doubt global warming will lead to human extinction. Life might get
harder in lots of ways, but it seems extremely unlikely to be an existential
problem.

~~~
Emma_Goldman
Sure, but there's a small chance that it will bring about the end of modern
civilization. In that sense it will be civilization-ending. An interesting
question is whether humans would be able to rebuild civilization after events
like this.

I think the main extinction risk is the secular trend for technology to become
both more destructive and more decentralised. If that continues, it might only
be a matter of time before independent actors will be able to extinguish the
human race. And given the distribution of human motivations, if individuals
can do it, someone will sooner or later.

~~~
jeffreyrogers
I can see the civilization ending argument, although it seems like something
resembling modern civilization could be rebuilt, maybe with less access to
energy, but with less people you also need less energy, so I'm not sure how
big of a problem that will be. Maybe without global industries there won't be
the materials science necessary for space exploration.

I have a harder time believing independent actors can extinguish the human
race. Biowarfare/terrorism is unlikely to do so for a variety of reasons, and
nuclear warfare only has the potential to do in superpower level conflict, and
even then I don't think it's certain.

~~~
acqq
> human race

Being satisfied that some "naked apes" still living could mean a survival, as
a biological species, of the probable destruction of current civilization is
setting the bar really low.

~~~
jeffreyrogers
Okay, but do you really think civilization is going to collapse entirely? I
don't. Even if half of humanity died you would still have civilization of some
sort.

------
dougmwne
Does anyone have a detailed analysis of why we believe we have the technology
to detect distant alien civilizations? Given interstellar distances, travel
between stars seems unlikely without some new science we don't know yet. Also,
do we know we would be able to detect our own radio transmissions with our own
telescopes from lighyears away? I think the great filter hypothesis always
relied on the assumption that intelligent life would eventually develop Star
Trek level technology and be extremely detectable, but what if we're near the
end of what's physically possible with respect to energy production, speed,
radio astronomy, and communications? What if the aliens are out there, but
statistically so far away that we will never detect each other?

~~~
Emma_Goldman
One issue with the way Bostrom and others frame the Fermi paradox is that they
assume the teleological end of any intelligent civilization will be the
maximisation of its exploitation of natural resources through the creation of
self-replicating probes that will slowly populate the universe. _That 's_ why
they think the Fermi paradox is a paradox - if there is life, it should be
everywhere. That may well be a reflection of ourselves, however, rather than a
universal motivation of intelligent life.

~~~
philwelch
At the numbers we’re looking at, even if only 1% of civilizations (maybe even
1 in 1000) would be exponentially expansionary, they would still make
themselves fairly obvious and outcompete all the others. The Fermi paradox
doesn’t assume that _all_ extraterrestrial intelligence behaves this way, but
this rebuttal has to assume that _no_ ETI would behave this way.

And that seems improbable, if only because aggressive, exponential expansion
is a fairly valid Darwinian strategy.

~~~
acqq
> aggressive, exponential expansion is a fairly valid Darwinian strategy.

Earth exists for around 4.5 billion years, life on Earth for 3.5 billion
years, the whole known Universe just less than 14 billion years (and we can
send some small probes to the limits of our own Solar system only during the
last decades). So the Universe is not "old" and the distances between the
areas suitable for the life to "expand" are immense and real barriers.

Knowing the distances involved, I believe that had we discovered that we are
in much later age of the Universe, not seeing "others" would mean more than it
means now. For now, knowing the distances, whatever could be somewhere far
could simply be too far from us, nothing more.

Edit:

Re: "The galaxy is only 100,000 light years across" note that that are the
_light_ years -- the distance that the light has to travel that much. We know
that the whole islands on Earth were unreachable for many otherwise common
species for millions of years. But these distances are nothing compared with
problems of maintaining complex life over the cosmic distances and in the
cosmically hostile environment. Also "10-50 million years ahead of us" doesn't
have to mean what we think it could mean. For a context, the dinosaurs were,
historically, 60 million years "ahead of us". Nobody can "just assume" the we
will cross the limits that are ours limits now. Biologically, we did multiply
"exponentially" as soon as we were able to use the natural resources to do so
(1). But apart from that (the certainty of life using available resources for
biological growth), the growth in technical capability for interstellar travel
is not guaranteed. Not to mention that the resources are by definition
limited.

So nobody should ask "why aren't others here" when we can't even claim that we
reached somewhere else. What we surely can ask is "why don't we get some
signals" because, for example, we are able to send a radio message, but I
personally wouldn't assume that the other civilizations make such kind of
intentional signalling that we must necessarily be able to detect, being where
we are now. It's not "just connect the headset to the wire and a crystal and
listen." It's something that has to concentrate immense amounts of energy to
reach exactly us. At the moment it's not "is there anybody anywhere" but "is
there anybody in the conveniently close neighborhood who's capable to send
exactly what we expect to receive, and, most probably, to target exactly in
this direction." It's immensely hard to even "see" the planets by the closest
stars, that how far everything is. I think that probability for that "targeted
messaging" is too low, not to mention that I don't think that the
"intelligence" in our sense is inevitably happening on every planet -- we know
that from the 3.5 billion years of life on Earth, not even plants existed for
3 billion years. Life can indeed be relatively common but the development that
the Earth up to now had could still simply be uncommon enough.

1) [https://ourworldindata.org/grapher/world-population-
since-10...](https://ourworldindata.org/grapher/world-population-
since-10000-bce-ourworldindata-series)

~~~
philwelch
If you’re going to reply to me, please reply to me instead of editing.

~~~
acqq
> please reply to me instead of editing.

Unfortunately, my account has some very, very low limits on the number of
replies I can make per day, which I can't influence. Not all users have
necessarily the same possibilities, and the privileges one may have aren't
universal.

My belief is, the limits are there to prevent the discussion progressing too
fast and if somebody misses some edit and that even helps the thread remaining
slower, maybe the measure still achieved a goal. But I admit it can be
confusing.

Of course, I'd personally prefer to have at least a bit higher "quota."

------
PlotCitizen
This article reads alarmingly similar to the Kurzgesagt video about the great
filter
([https://www.youtube.com/watch?v=UjtOGPJ0URM](https://www.youtube.com/watch?v=UjtOGPJ0URM)).

Of course, the Great Filter isn't a new concept, but provided that this is an
argument made by somebody other than the person who coined the term (that was
Robin Hanson I believe), combined with the fact that I read almost the entire
article before then going on to find the video, I find the two too similar to
write it off to simple chance.

There have been criticisms of Kurzgesagt in the past, one I can recall being
the following, in video form ([https://www.youtube.com/watch?v=q2dAGU-
VJcE](https://www.youtube.com/watch?v=q2dAGU-VJcE)). I've now found out that
the original video was retracted and the creator issued a public apology
([https://www.youtube.com/watch?v=WcgHGslVdrg](https://www.youtube.com/watch?v=WcgHGslVdrg)),
in addition to Kurzgesagt committing to performing more scrutiny over their
videos and citing their sources wherever possible.

I do applaud this last step on their part, and I understand that you have to
admit that the Great Filter video was published back in 2018 before this
commitment was made, but something about the lack of attribution throughout
the video doesn't sit right with me, still.

~~~
TeMPOraL
FWIW, Great Filter is a really simple idea, and it's very well known in
certain circles (e.g. LessWrong community, to formation of which Robin Hanson
contributed). I personally had no idea Robin coined it, or that Bostrom wrote
about it, despite reading some text of both - and yet I could still give the
same explanation way before Kurzgesagt's video aired.

Which is to say, I didn't find the lack of attribution worrisome in this
video, because the idea is pretty much "public domain" in the circles
interested about the future. It was (as you note) before the time when
Kurzgesagt decided to get super-thorough about citing their sources, and I
charitably assume that the authors of the video were just aware of the concept
of the Great Filter, and not necessarily where they learned about it from.
It's a simple idea, easy to explain, and easy to make inferences from - so it
may not have occurred to them it's worth tracking down who originally coined
the term.

------
ravitation
Honestly, I find the argument that some specifically destructive event (or
even a collection of events) would be pervasive enough among all intelligent
species to serve as a "Great Filter" to be completely absurd. The chances that
any of the examples he listed actually resulting in full extinction (or even
an endless spacefaring handicap) are only moderate at best, not assured, even
if they did occur. In fact, I think it's quite reasonable to expect that a
species, having undergone such a destructive event and been left not extinct,
would actually be pushed into space far more efficiently. With that in mind,
it's certainly completely absurd to actively hope that monumental (possibly
species altering) discoveries are not made.

------
jonshariat
I always thought the notion of the "von Neumann probe" was odd. What is the
motivation for a civilization to do this? It would be highly destructive,
extremely destructive, and impossible to reverse. No one would set this in
motion, right?

~~~
gamegoblin
Consider that, to a very alien intelligence, humanity could look a _lot_ like
von Neumann probes.

If we stay on our current technological trajectory without destroying
ourselves, we will spread out into the galaxy, consuming more and more
resources in order to produce more copies of ourselves.

From a totally alien point of view, we might be as intelligent, conscious, or
sapient to them as trees are to us. That is, we might as well be bio-robots.
Von Neumann probes.

------
jeffreyrogers
I've always found these Fermi paradox arguments silly. Just by posing the
problem in this way you are making lots of implicit assumptions which you
pretend aren't there by dressing up the rest of your argument in faux rigor.

~~~
jules-jules
What are some of the implicit assumptions in your view?

------
voodoomagicman
This is newly interesting in light of the recent pentagon UFO revelations
([https://www.nytimes.com/2020/07/23/us/politics/pentagon-
ufo-...](https://www.nytimes.com/2020/07/23/us/politics/pentagon-ufo-harry-
reid-navy.html?action=click&module=RelatedLinks&pgtype=Article)). While these
have low credibility, and even if true are likely not extraterrestrial,
finding life on mars would change this calculation.

~~~
acqq
> these have low credibility

Lower then low, to the point that whenever somebody mentions them, I believe
there was just a "wish to be true" and then stop.

When checked, it was just a "rerelase" of the old already published material
(one can also think about to whose benefit that distraction was) which was
already carefully debunked by Mick West:

[https://www.youtube.com/watch?v=Q7jcBGLIpus](https://www.youtube.com/watch?v=Q7jcBGLIpus)

Mick West's full playlist with explanations:

[https://www.youtube.com/playlist?list=PL-4ZqTjKmhn5Qr0tCHkCV...](https://www.youtube.com/playlist?list=PL-4ZqTjKmhn5Qr0tCHkCVnqTx_c0P3O2t)

An article mentioning Mick West:

[https://petapixel.com/2020/04/28/that-navy-ufo-footage-
has-a...](https://petapixel.com/2020/04/28/that-navy-ufo-footage-has-an-
optical-explanation/)

Also, one day after NYT published their article "No Longer in Shadows,
Pentagon’s U.F.O. Unit Will Make Some Findings Public" they published a
correction too:

"Correction: July 24, 2020 _An earlier version of this article inaccurately
rendered remarks attributed to Harry Reid_ , the retired Senate majority
leader from Nevada. Mr. Reid said he believed that crashes of objects of
unknown origin _may have occurred_ and that retrieved materials should be
studied; _he did not say that crashes had occurred and that retrieved
materials had been studied secretly for decades._ An earlier version also
misstated the frequency with which the director of national intelligence is
supposed to report on unidentified aerial phenomena. It is 180 days after
enactment of the intelligence authorization act, not every six months."

Emphasis mine, now imagine how many articles in how many media were written
before the above correction, and it will explain what most of the consumers
got as the message (namely, the first, utterly fake version with fake
"crashes").

------
piptastic
Not sure I buy this argument... here are some random thoughts on why:

1) Someone has to be first. Let's say that there is no filter, and every
species that doesn't destroy itself or get destroyed will eventually become
technologically advanced to travel around meaningfully in space. There is a
certain amount of time it will take for this to happen. Supposedly the
universe is ~14B years old, and Earth is ~5B years old. It takes a certain
amount of time for abiogenesis, a certain amount of time for life to evolve,
and a species to emerge "victorious" long enough to start conquering the
universe before the next extinction event. So we could be the "first", or the
top 20% anyway, and it'll still take us a while for those top 20% to get
anywhere where they can start detecting/traveling anywhere.

2) What is the maximum distance any extraterrestrial life could observe our
technology/planet currently? Space is huge, like uncomprehendingly huge...
even if we could go anywhere ourselves right now, would we go visit every
single planet everywhere without a reason to? And how long would that take?
Maybe there hasn't been enough time for a civilization to a) detect us from
100s of light years away and b) travel to us. Maybe detection of life from far
away is impossible past a certain point, but traveling there isn't (since it
just takes time).

So I guess my thought is, yeah, we might not find life in our solar system,
but we might. But even if we do, I don't necessarily think we'll get filtered
out either.

~~~
gaukes
I'm not so confident we're in the top 20%. Our galaxy is middle-aged. Our star
is only 4.6 billion years old in a galaxy that is 13.51 billion years.

There were several stars that blew up before we got the sun which means
several systems and planets right in our neighborhood and that's just 1 star
in the entire milky way.

Even at 1% the speed of light, it would take 2 million years to travel across
the milky way which, relative to the age of the galaxy, is nothing.

~~~
piptastic
Sure, but let's say you're on the other side of the milky way. You can travel
at 1% the speed of light. Why would you come to Earth or anywhere near it? It
takes 2 million years to get here, so unless you know something is there, that
would be an insane trip to make.

~~~
gaukes
Well, they wouldn't be looking for Earth specifically, they'd be looking for
more resources which are everywhere. An intelligent and energy-hungry enough
species would want to harness the power of every sun it can reach.

That growth would be exponential because acquiring resources provides more
energy which allows them to acquire more resources even faster.

If an intelligent species doubled the number of stars they control every 2
million years, they'd have every star in the milky way in around 50 million
years.

That's still like 0.2% the lifetime of the galaxy.

------
valgor
The thought that if the Great Filter is behind us and we kill ourselves is
more depressing than the Great Filter is ahead of us and we kill ourselves.
I'm not very concerned with which type of intelligent life expanses into the
universe so long as at least one type does it successfully. Being human, AGI,
or alien does not matter. So finding ETs or creating super power AGI would be
a win in my book because it increases the changes that someone will make it.

------
pmdulaney
The finding of extraterrestrial life wouldn't destroy my Christian worldview,
but it would make things much less tidy. In his Mere Christianity, as I
recall, C. S. Lewis opined that there probably was other intelligent life in
the universe (i.e., other than God and the angels) and it left a bad taste in
my mouth.

------
jackfoxy
I don't agree with the assumption of a single great filter. Why not many
sufficient enough filters. Maybe one occurrence of any is sufficient to
locally halt forever evolution to space-faring civilization, or successive
occurrence of arbitrary filters at arbitrary intervals suffices.

~~~
dyro
The author states the great filter could be composed of multiple filters
towards the end of the paper.

> Nothing in the above reasoning precludes the Great Filter from being located
> both behind us and ahead of us. It might both be extremely improbable that
> intelligent life should arise on any given planet, and very improbable that
> intelligent life, once evolved, should succeed in becoming advanced enough
> to colonize space.

~~~
jackfoxy
Thanks, got bored and stopped reading before I got to that.

------
methodin
If it was discovered that the laws of nature prevent a species from expanding
into the universe through whatever mechanisms plausible, what would that do
the idea of free will? Does free will require unbounded possibilities or would
an upper bound rethink our idea of the universe?

~~~
russholmes
There is no such thing as free will, is there? Decisions are a consequence of
physical brain state.

------
reeealloc
The big assumption here that really bothers me is that any civilization that
developed the technology to expand into the galaxy would've found us by now.
That's so bogus. We can probably expand to Mars, but we're still bound by the
speed of light.

------
motohagiography
What do we typically believe now that we would no longer believe if there were
an advanced species benevolently not hunting us for sport?

I am trying to sort out what are the moral and ethical implications of humans
not being the most intelligent or advanced species it is aware of.

