Extraterrestrial Languages by Daniel Oberhaus is a whirlwind of topics surrounding the problem of how do we communicate with aliens. Starting all the way at the founding of the field to the future of what’s to come, he covers a lot of ground, but I thought I’d write down a few of my favorite motifs and ideas from this book.

This is less a “book review” and more of a “cool things I thought of while reading”. Make of it what you will.

How to tell if life on Earth is intelligent?

The first step to detecting extraterrestrial life is being able to find signs of life at all. How can we separate life from non-life on Earth and how do we identify if they’re intelligent? One way to do that is with information theory and studying how basic linguistic units relate to one another.

In human languages, we can find statistical similarities between languages. For instance, most languages follow something pretty close to Zipf’s Law where the most common word is twice as common as the next one. If we think about language as being composed of layers (letters, words, 2 word combos, etc.), then you can detect patterns that gradually fall off as you get higher. While two word combos have a wide range of frequency, you’d struggle to find any coherence when studying what effect 9 word phrases have on each other.

Using this though, how would we identify something like the fibonacci sequence? If someone was broadcasting it and all we had was a measure of entropy, we would see it as just random noise. Rather than even demonstrating intelligence, anything you communicate also has to have the potential for intelligence.

I don’t think there’s a concrete way to solve this problem. Rather, you have to send messages that demonstrate the ability to contain information.

Side note: It’s interesting how this views communication from a purely statistical view rather than any “universal grammar” way. Especially with the rise of LLMs, it’s been hard to view language as anything other than a very dressed up linguistic parrot.

How do they learn our language?

Space is too large to continue a real conversation. Rather, we’d have to send something that is self-decodable so that the aliens are able to learn our language and understand us through languages we can write.

• What is the minimum corpus we could send to produce good translations?
  • How do ensure that cultures are equally represented in our views of the world?
• Given no knowledge of what senses they have, could we somehow always translate every sense we know of into text? Maybe something like binary as a basic language.
• If qualia is unique and has to be experienced to be understood, is it possible that trying to communicate what it is to be human is entirely impossible?
  • Could we create a device that truly allows us to feel what someone else is feeling?

Is there a universal language?

If you were to devise a universal language, even just across humans, what would it be? For many people that would be math, but is math something that just exists because of how we interact with the world or do mathematical objects truly exist outside of humans? What seems like an empty philisophical parcularity has a lot of importance when it comes to how we try to communicate with aliens. Sure, they probably won’t use Base 10 (that’s an artifact of our 10 fingers (also known as digits!)), but will they even have similar mathematics? Will evolution have converged on similar mathematical systems for all sufficiently intelligence creatures? What would it even mean for organisms to have a different system that didn’t rest on a foundation of set theory?

Side idea: Even communicating to future humans is tough

For instance, how could we signify to humans 10,000 years from now that they should not open up our bunkers of nuclear waste. If you think communicating with aliens is hard, it’s just hard even to communicate with our own species. Communication rests on this bedrock of shared understanding.

If you think it isn’t that hard, do try and come up with some ideas. Even something you might consider to be a 1-to-1 correspondence to the notion of death like a skull is really just a cultural artifact. We’re so immersed within our own culture that it’s hard to imagine symbols could change to become exact opposites of what we currently believe.

Is evolution truly open-ended?

What kind of alien life should we expect to find? If evolution is open-ended, then life could be just about anything within physical bounds, but it might also be possible that our scary “aliens” look similar to humans. Maybe convergent evolution has found our bipedal human forms to be a good vessel for higher intelligence across the galaxy. If that’s the case, are there assumptions we can make about the kind of culture they have? Perhaps metaphor making is a foundation for all higher level intelligence, so we’d be able to connect over that.

Should we even broadcast messages to space?

Besides the cost of maintaining very long messages across space, is it potentially dangerous to advertise our existence? Looking at human history, technological imbalances between human groups are usually settled by one group conquering the other. Not a very bright outlook for the human species if we suddenly find aliens that are advanced beyond our imagination.

If you’ve read the Three Body Problem, then you’ve probably heard this idea packaged as the “Dark Forest Theory”. Space might be full of life, but if you can never be certain of the other civilization’s intentions and capacity for technological leaps, they will always prove a threat to you. Because of the large distances across the universe, it is always safer to destroy them and remain silent rather than trying to cooperate.

Who are we?

The original Arecibo messages give a sense that the only life on Earth was only humans. The golden plates we sent on the Apollo spacecraft were very ethnocentric. Even if we broadcast all of these, they give the sense of humans as brave explorers, curious scientists, and not the same humans who fight bloody wars over bigotry.

In thinking about how we want to come across to the galaxy, we have to define what it even means to be human. Who are we as a species? Given that someone knows nothing about us, what is right for us to tell them? Even if the odds of contacting an alien are infinitesimally small, just having to think about what we would communicate helps us view our species from a broader lens.

Can we rise to the image we broadcast into that infinite ether? Would aliens turn away in disgust at not only what we do to one another but our Goldilock’s planet?

Whatever we send out into space becomes the de facto definition of humanity.