In a press release dated Wednesday, October 23, 2019, Breakthrough Listen announced its collaboration with NASA and the space agency’s Transiting Exoplanet Survey Satellite (TESS). TESS is expected to add thousands more to the thousands of exoplanets already discovered. The collaboration means that Breakthrough Listen will now have specific directions in which to listen and look both for extraterrestrial signals, signs of intelligent life and technosignatures—signs of advanced technology.

Some exoplanets are in the “Goldilocks zone,” meaning that their distance from their sun likely permits the existence of liquid water, essential for life as we know it. Listening for the radio sounds of extraterrestrial life and for other technosignatures, SETI, the search for extraterrestrial intelligence, has become an industry. True, so far we have found no extraterrestrials and no one (as far as we can ascertain) has visited us; this is Fermi’s Paradox, the “if they exist where are they?” issue—but there could be many reasons why we have yet to detect other intelligent species.

For one thing, most of them, like most intelligent species on our own planet, are probably not technological. Then, too, the span during which a high technology species both can and might wish to make contact with a relatively low-technology species such as our own may be limited. Technological species may even regularly destroy their capacity for interstellar contact, something that not inconceivably could be our own fate. Perhaps other intelligent species are simply not interested in us, their evolved curiosity driving them in other directions. Most likely (in my opinion), we aren’t very interesting to them, at least not yet.

How relatively easy it is to study child development, with billions of children growing up all the time, each with a brief and comparable trajectory. How hard it is to study the development of a high-technology species, with an n of 1 so far and a developmental trajectory of tens of thousands of years.

Worse, that one intelligent species we do know about has not (I hope) finished growing up. Worse still, perhaps the very idea of “species maturity” is a misguided analogy, and all we will ever have is history’s rather random walk.

If we are to mature it will require us to become less self-destructive; we must increase kindness and compassion and decrease murder and mutilation. It must include an end to environmental destruction. In practical terms, our growing up is likely to be associated with continuing technological development and change, making greater achievements possible while creating dangerous challenges. In a sense, we must move to a new neighborhood.

One aspect of the U-Haul rental that could take us there is our increasing recognition of other species as having their own kinds of intelligence and their own rights. Even as biodiversity shrinks and extinction rates soar, many of us are learning to think of the entire planet as our community.

Species maturity also means that we are learning that “home” is broader than our planet. We are rapidly becoming a spacefaring species with the necessary technology and investment being generated by competition among nations, billionaires and immense corporations. In the future, we will mine asteroids and create manufacturing bases on the moon. Even more exciting, today’s space exploration emphasizes the search for microbial life elsewhere in our solar system, or at least for the possible building blocks of life.

No one today anticipates finding intelligent, high-technology organisms anywhere in our own planetary system, but seeking life on other planets and their moons makes it easier to accept that the community in which we live does not end at the outskirts of the solar system. If it did, what a pity, as a mature species may need neighbors.

We humans are reputational animals and spend a great deal of waking time working on influencing the perceptions others have of us. Who has not, after a social event, lost sleep in what the French term l’esprit de l’escalier, the spirit of the staircase—the belated awareness of what we should have said or done but didn’t think of until we were on the stairs on our way out. We dress and groom and paint ourselves to control how others see us, and we often choose our cars, our neighborhoods, our occupations and our music with the opinions of potential onlookers on our minds.

These are individual dynamics, but they apply to groups, too. Collectively, we hold parades, build armies and weapons of mass destruction and even space vessels to influence the opinions others have of us. We provide aid to other countries, or at least strive to present our international activities as altruistic, in a sort of collective impression management.

So, what if we began a conversation with extraterrestrial intelligences? Such a conversation would be slow, given distances so vast that the speed of light still feels relatively slow. The major impact of interstellar communication may be not so much what is communicated but simply the evidence that they are there, that there are others whose good opinion we desire—others who are potential enemies or allies. Awareness that we are not alone may make us a morally better species in the way that the religious belief in an all-knowing, invisible but caring being makes many of us follow codes of behavior.

And this brings us to METI, messaging (rather than just listening for) extraterrestrial intelligence. In its own gentle and subtle way, METI helps move us along the path of species maturity. It gets us thinking about the neighborhood because it involves knocking on the doors of houses that may be empty or hold only the uncaring but could also, in fact, hold people whose good opinion we want to cultivate.

But what of the risks? Suppose a door we knock on belongs to aliens out of H.G. Wells’ classic War of the Worlds? Let’s go back to Fermi’s paradox for a minute and borrow its logic: If the extraterrestrials are so hell-bent on destroying other species, then why aren’t they already here? After all, we have been sending radio waves into space since the invention of radio. A species that evolved to see others as competitors to be destroyed and could and would respond to our efforts at contact with weaponry capable of destroying life on Earth. They’d probably already have launched probes to Goldilocks-zone planets and detected signs of our technology: Should we live in fear, even shut down electromagnetic communication and rely on cables only?

Full disclosure: I am the author of a paper arguing that an automatically hostile-to-others intelligent species could evolve. Suppose a species evolved its intelligence as a result of lethal competition with co-evolving other species. The winner might presumably have been selected for automatic hostility to intelligent aliens. Modern humans appear to have evolved (as far as we know) without conflict with other intelligent species, though we did overlap and presumably compete with two distant relatives, the Neandertals and the Denisovans. While it is clear that we mated with both of them—non-African populations have some of their DNA—we may well have fought with them, too. However, we apparently were not selected for obligate hostility towards other intelligent groups, whether of our own or another species.

Yes, we can all too readily learn to be antagonistic towards those with an appearance slightly different from our own, but we can also readily learn to befriend them and intermarry with them. Even if my original argument was correct and there are potentially deadly enemies out there, the probability of their existence times the probability of their existence times the probability they have the technology to do us harm over interstellar distances, is vanishingly small. This tiny danger must be weighed against the likelihood that contact with other species will help us to mature and lessen our own internecine conflict.

If we place METI in the frame of the maturation of our species, it becomes neither a danger nor a selfish diversion of resources badly needed for other purposes. Rather, it can be seen as a modest but significant part of humanity’s maturation. Compared to space vessels and moon landings, it is very inexpensive, a small bet on what some would consider a low probability risk but with a potentially immense payoff. Just placing the bet makes us think about possible neighbors and what we would want to say to them and what we want them to know about us: and such thinking is in itself a step towards species maturity. In ancient times, we looked to the stars for guidance (some still do); today we need to look to them for neighbors and witnesses to our species’ trajectory.