[This article is reprinted from Hackcircus #4, 2014. I recommend this magazine for many of the other issues and articles, which are wild and varied in theme, idea, and presentation.]
How would we know that we have encountered extraterrestrial intelligence (ETI)? What would distinguish ETI from unintelligent aliens (like the parasite in Alien) and intelligent terrestrials (us)?
It may seem obvious that we can come up with an answer. We know of some intelligent things – ourselves. And we know about extraterrestrial things – planets, stars, interstellar clouds of vinegar. One kind of ETI could be a combination of the two together: things like us, but from space. Consider the tall waving alien at the end of Close Encounters of the Third Kind.
But it is not enough to give an easy example. We cannot assume the first ETIs we meet shall be just like us. How they might not be like us makes it hard to identify them at all.
1 Does It Matter that We Recognise Extraterrestrial Intelligence?
Say we encounter something extraterrestrial which has something we want, such as a mineral. If it is not living, e.g., an asteroid, there seems to be no moral obstacle to simply taking it. Even if it is alive, e.g., extraterrestrial bacteria, there is no immediately obvious obstacle. We take something essential to another living thing every time we eat. But there are ethical issues if ET is in any way intelligent. If something has the capacity for self-awareness, it looks safe to assume that it can suffer and there is some moral obligation toward it.
Of course, we might not care about that. Even if it suffers or is self-conscious, we may decide to take from it anyhow. But this assumes the situation is one in which we are the ones taking. The more likely situation is one in which ETI can take something from us. If intelligence only evolved in this Solar System on Earth, it’s more likely that we’ll encounter ETI which travels to us. It survives well enough in space, an environment in which we have barely touched. If it can also enter our atmosphere, then it also can survive somewhat on Earth.
You can’t reason with unintelligent things. An asteroid rushing toward the Earth is not slowed by arguing for your rights. Alien bacteria chemically synthesizing flesh is not moved by suffering. But if you can make yourself understood, you can at least ask an intelligent alien to stop what it is doing – to slow down; to eat something else.
If it recognises you. In his short story ‘The Things’, Peter Watts narrates Carpenter’s ‘The Thing’ from the perspective of the alien. It is a compassionate, intelligent being which does not understand humans at all. It is horrified by us. Sees us as empty and blind, lacking sentience, self or feeling.
Perhaps there is one feature unique to intelligent beings. Like us, ETIs use language. If we encounter an extraterrestrial language, then we know that there is intelligence behind it.
Here are three ways we might encounter an ETI language:
(a) Communication aimed at us by something that understands us.
(b) Communication aimed at us by something that does not understand us.
(c) Communication not aimed at us at all (and which we only coincidentally encounter).
(a) is relatively easy to identify, as easy as a broadcast in a familiar human language. (b) is a common target of SETI and relatively simple as well. Intended for us (the aliens to the communicating ETIs), it should include patterns strongly indicative of intelligence, patterns which do not naturally occur but which all intelligent beings should know, e.g., sequences of primes.
These sequences make sense if ETIs tries to communicate with us. Yet, it’s reasonable to think that most ETI signals we pick up, aware of it or not, are (c): they are messages ETI is sending to itself. Human-directed broadcasts by humans (e.g., TV broadcasts) far outweigh ETI-directed ones (e.g., the Voyager probes). This is something we should assume is true of ETI as well. We are more likely to be eavesdropping than be involved in the first ETI we hear.
Whether or not we recognise it. Given an influential theory of language development, we may not be able to tell eavesdropped ETI conversations from noise.
According to Chomsky’s theory of language acquisition, the available linguistic data surrounding an infant (e.g., parents’ speech) is insufficient for the infant to learn that language. Yet nearly every infant learns the language which surrounds them. Chomsky posits what Kukla calls the Innateness Hypothesis: An infant is born with something, an innate module, to supplement the environmental data. And, as infants can typically learn any language, this module uses a ‘universal grammar’.
The psychologist Kukla argues that this raises a problem with communicating with ETI. Chomsky’s universal grammar applies only to human languages. It is not evidence that any language shares the grammar. If the grammar is only ‘universal’ for humans, one lacking the innate module can’t learn it the way one who possesses it can. If the module is necessary to learn it, those without it cannot learn it.
If our innate language modules evolved, then ETI and we are unlikely to share the same innate modules. We do not share the same evolutionary history.
One way out of this is convergent evolution. Perhaps the same module and grammar evolves under similar environments. Perhaps those environments exist in other places than Earth. If so, then we may encounter ETI which we can understand and which can understand us.
This still leaves out all the other possible environments in which ETI may have evolved. If those other environments are more numerous than those like ours, then we are more likely to encounter an ETI from them. We are more likely to pick up their signals. If Chomsky is right, we will not be able to comprehend them.
Perhaps we can avoid using language to detect ETI. Perhaps ETI does non-linguistic things that indicate intelligence. Especially if we have a close encounter with ETI — on its own world, in deep space, on Earth.
Here is one non-linguistic possibility: ETI exhibits awareness of mathematical, chemical, biological and physical principles. They are more technologically advanced than us. They turn up in gigantic starships hanging effortlessly in the sky. Their hulls are constructed of complex difficult-to-comprehend chemical alloys. When one of them is injured, they heal using advanced medical procedures.
Such traits may convince us that the extraterrestrial before us is ETI. Advanced technology seems inconceivable without engineering plans, invention, devised and tested theories of physics, chemistry, an understanding of the body.
Yet, only recently did we grasp how bees fly: their flight was once thought impossible. As the philosopher Dupré notes, not humans but microbes are “the most versatile and effective chemists in the biosphere” (Dupré, p.37). And next time you cut yourself, look at the scar. Your body is repairing itself in a way no current doctor can.
All of these processes occur due to natural evolution — by definition, an unintelligent blind process. They are far more advanced than anything we can do now.
The complex giant ship hanging over your city may be the extraterrestrial equivalent of lichen.
There is one significant difference between lichen and that ship. Size. Lichen doesn’t grow that big or spread across space.
One of the main reasons Earth life does not grow so huge is because of gravity and heat. The different sizes and shapes regulate body temperature, allow movement, and allow creatures to eat. Elephants do not look like mice. Humans have soft tissue on the outside. Without it, when we move we would easily break. Insects, which are smaller, have no need of that tissue. A real Godzilla could not walk or even breath; he couldn’t even cool down.
Yet, ET does not need to be so restricted. It did not evolve here on Earth. If an ET evolved, say, in the depths of an interstellar cloud, it is not clear what size or shape it could be. The morphology and scale of extraterrestrial life, including intelligent life, could vary as widely as extraterrestrial environments allow.
The only reason to deny this possibility for intelligent aliens is if intelligence can only survive for any significant time in Earth-like environments. But if intelligence can only survive in Earth-like environments, then no ETI has crossed space to arrive here. Nor shall we ourselves ever make it to meet them on their own world, or anywhere in-between.
There is a final way that size and shape might indicate intelligence. If ETI turns out to be the same scale as us, then, given the wide range of options, this would be so much a coincidence that it may be better to think it is intentional. The ET is copying us. It’s difficult to understand how this could be possible through natural selection. They didn’t evolve with us to mimic us. They would have to do it on arrival. The better explanation is they have studied us. These human-sized things may be like costumes worn to raise whooping cranes.
That an ETI copies us, then, may tell us that it is intelligent. But it does not mean that it recognises our intelligence. That may be the more important challenge: how to convince ETI that there is terrestrial intelligence.
Just ask the ‘Thing’.