Tuesday, August 15, 2023

Positions I Don't Hold: Alien Life Exists

The first in a series of posts of ideological turing tests.

Ideological Turing Test:

Extraterrestrial life certainly exists somewhere else in the universe.  It isn't a matter of if, but when we find it.  By extraterrestrial life, I mean complex, intelligent life capable of civilizations and technology.

We haven't found any yet, but that doesn't mean they aren't out there.  There are solid scientific reasons to think that other intelligent lifeforms exist, even if we have not encountered them yet.

Firstly, it's hardly surprising we haven't found other lifeforms.  We've only really been in any position to detect aliens in the universe for a few slim decades.  It's been about one century and a half that humans have been detectable to aliens, even less time that we've been able to observe beyond our own solar system.  Denying the existence of aliens on the basis of our current knowledge, is akin to going into a dark room, shining a flashlight for a few seconds in one corner, and concluding there are no spiders in the room.  

Given the enormous scales of the universe, both in space and in time, it would be stupid to assume that if aliens exist anywhere in the gigantic, unexplored universe that we should have found evidence of them already.

Astronomers are looking.  But in the meantime, we have good reasons to think intelligent life exists out there.

When we look at our own tiny piece of the universe, Earth, we see an immense diversity of life.  Everywhere possible that life can exist, it does.  It finds new forms, adapts in new ways, develops new abilities, in order to survive wherever it has not already reached.  From the depths of the ocean to the heights of the sky, the earth is full of living things.

The earth is full of living things because life is anti-fragile.  When presented with hardships, living beings actively improve themselves in order to survive and continue to flourish.  Think of how hard it is to get rid of pestilent insects like flies and moths; because no matter what we do to eliminate them, they adapt and return in the same numbers.  It is a general feature of life that it does this, so we should expect the pattern to hold across time and space.  Life should be everywhere it can be, and even some places it can't.

When we extend our observations on the earth to the heavens, we should expect to find life in every possible place it can be.  While there might not be many planets that could support life, we should expect every place that can support life to already have life on it.

Being home to lifeforms does not have to mean "earth-like"; even on the earth, there are biomes that are decidedly not "earth-like" yet still support living beings.  So how many planets out there could be home to lifeforms?

The universe is enormous.  It is so unfathomably enormous we can't even conceive of the number of galaxies in it.  Each galaxy is made up of an unfathomable number of stars.  And each star might have several planets in orbit around it.

To express the numbers, scientists usually have to resort to just counting the zeroes at the end.  Within the known universe, there are trillions of galaxies (10^9).  Within each galaxy, there are trillions of stars (10^9).  And each of those stars has several planets orbiting around it (say 10).

An important principal in astronomy and cosmology is the Copernican principle.  It is the principle that we should assume the same laws and principles where we cannot observe, as we observe where we can.  In our solar system, we can observe several planets, and it is conceivable that several of the planet-like bodies (including moons of super giants) in our own solar system might be habitable.  So it is reasonable to assume other solar systems are similar.

Doing some simple math, not trying to be exact about numbers but just trying to get a ball-park estimate, we expect something on the order of 

(number of habitable planets) = (number of galaxies) x (number of stars in galaxy) x (number of habitable planets per star) = 10^9 x 10^9 x 3 = 3 x 10^18 = 3,000,000,000,000,000,000

planets that could give rise to life out there in the observable universe.  That number is 3 trillion-trillions.

Given this enormous number of possibly habitable planets, given what we observe on our own planet about the tendency of life to spread everywhere it can, it is inconceivable that absolutely all of these planets are barren and lifeless.  Even if we have no direct observational evidence of it yet, the burden of proof should lie on those trying to claim that every single one of these trillion-trillion worlds is barren.

Even if the odds of life are small, there are so many planets that it is bound to happen.  Thus, there almost certainly exist extraterrestrial lifeforms.  It isn't a matter of if, but when we find them.


This is what I consider the strongest form of the belief in alien life.  It might not be the position that most adherents hold, but it is the position I find least reason to object to.

Life exists outside of the earth.  However, the life that exists is not in a form we would immediately recognize, nor be able to meaningfully interact with.

This is somewhat of a let-down.  When we speak of extraterrestrial life, we are really talking about finding Vulcans and Klingons.  That is, humans with rubber foreheads or ears.

“Man doth usurp all space,
Stares thee, in rock, bush, river, in the face.
Never thine eyes behold a tree;
'Tis no sea thou seest in the sea,
'Tis but a disguised humanity.
To avoid thy fellow, vain thy plan;
All that interests man, is man.”
― Henry Sutton

In terms of bipedal, intelligent, communicative, civilization-forming, possibly interspecies-breeding life out in the universe, almost certainly not.  But in terms of anything that could meet the basic definition of life, almost certainly so.  We just need to reimagine what we're looking for.

Life is, basically, self-propagating information.  The information exists in an environment, but in a contained form separate from its environment.  The information is able to use its container to interact with the environment in ways that allow it to continue existing in its form.  It is also able to cause replicas of itself to exist within its environment.

This could describe bacteria.  But it could also describe automata in Conway's Game of Life.  It could describe Wang's carpets.  It could describe life made of organic chemicals such as ourselves, or it could describe life that exists within a fourier transform of normal space made of frequency bundles.  

This is the kind of life that might be out there.

It isn't what we might hope for, but it is still a very exciting prospect all the same.  This kind of life, thus broadly defined, almost certainly has come to exist somewhere out there.  We might be looking right at it and not see it, but it exists.

Why I Don't Hold This Position:

It's true, just because we haven't found alien lifeforms, doesn't mean they don't exist.

The argument from anti-fragility is (mostly) valid in terms of life propagating.  But the problem isn't life surviving on different planets, but beginning there.  We're not arguing about evolution, but abiogenesis.  Technically, all the diversity of species of life on earth all still amount to a single datapoint, as all of it is traceable to a single origin.  That is to say, while we could drop a beaker of all the world's bacteria onto Mars and soon have life propagating on Mars... there are no bacteria on Mars unless we do.  

Life in, life out.  But if there's no life to start with, how do you get it?

That's the real question.  How likely is it for life to start on a given planet?  The answer is we don't know.

We know that we exist, but have no framework for even beginning to estimate the probability.

Supposing there to be N planets, where N is some astronomically large number representing the number of planets that exist in the entire universe, then our best guess for the likelihood of a planet developing life is 1/N.  And I mean statistically, this is the maximum likelihood estimator for the probability of a given planet having life, given our current data.

Since N is an astronomically large number, then 1/N is going to be very, very tiny.  Earlier, I estimated N = 3,000,000,000,000,000,000.  That means 1/N = 0.0000000000000000003.  In fact, in the limit of infinitely many planets in the universe, the probability goes to 0.

What is our best guess for the number of planets with life on them?  Following the simple math of something like the Drake equation, it is 

(number of planets with life) = (number of planets) x (fraction of planets with life) = (N) x (1/N) = 1.

One planet.  Ours.  That's how many we expect, given the data we have.

But this is a naive estimate.  We can do better than this.

I have done a more sophisticated look at the math of extraterrestrial probability in an earlier blog post.  We can also get a better idea of the probability of life by looking at the biochemical processes that go into it.

Life arising is a matter of protein formation and folding.  Eventually, proteins in the right shape are able to propagate, change, become more complex, and eventually begin complex behavior leading to life.  So looking at protein folding can actually give us a much more detailed estimate.

When we talk about proteins, there is so much that is important to their functionality.  The exact molecules and subpolymers are critical, the exact ordering of molecules and subpolymers, the exact shape, the precise angles between elements.  All of this impacts whether the protein will serve its purpose or be completely useless.  In practical terms, small differences in protein angle are the difference between normal health or debilitating medical conditions.

We defined N, the total number of planets in the universe.  Let's define M, the total number of possible and meaningfully distinct arrangements of proteins.  However large you think N is, M is larger.  Many times larger.  Take that number N, and tag on at least 6 zeros.

How many of those M can lead to self-replicating proteins?  Not very many,  The majority of proteins are just useless goop.

So the fraction of planets with life isn't merely 1/N, but more on the order of 1/M, which is even massively smaller.  Our simple Drake equation ends up at N/M, which is going to be very close to zero.  Using my rough estimates, we expect

(number of planets with life) = (3x10^18) x (1x10^{-24}) = 3x10^{-6}.

That is, we expect zero planets with life.  We have found 1 planet with life.

Notice, implicit in my analysis is the assumption of trillions of trillions of stars and planets and all that.  Yeah, the universe is a big place.  And life is just exceptionally special and rare.  

The Position I Do Hold:

While I'm more open to the idea of microbial lifeforms being possible, I don't think there is any life out there.  I especially don't think there exists intelligent life on the order of human beings.  We're it.  Everywhere else is empty, rocky wilderness.

Life is so exceptionally special and rare that I don't care how much you want to wax poetical about the size of the universe and wasted space and other warmed-over lines from Sagan.  We should be asking how it is that that it even happened once.  Because it's not going to happen again.

Clearly, it would just take one alien to prove me wrong.  But I'm not waiting.


As apparently the Mexican government is trying to claim an elementary school pottery project is an alien body, it's good to not have to wonder if this is true.  It's good to not have to wonder what the UFOs are, it's good to not have to wonder if the government will ever release real evidence, and it's good to not have to wonder if the evidence they release is real.  They're spy drones, they won't, it's not.

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