It is unclear how many intelligent civilizations have arisen in the Milky Way galaxy so far, but if some have, a pressing question comes to mind: were they or are they more intelligent than we are?
When reading the morning newspaper, it is difficult to avoid the thought that our own intelligence bar is not particularly high nor difficult to surpass. We fight among ourselves in “lose-lose” situations; we do not promote long-term solutions over short-term fixes; and we have been broadcasting our existence to the galaxy with radio waves for over a century without worrying whether about whether there are any predators or competitors in outer space. (If it’s the latter, they might have been ignoring us because we appear so incompetent.)
If other civilizations do exist, one key in becoming aware of them is whether we are intelligent enough to adequately interpret their signals or to identify a piece of their technology if it should appear in our solar system. One fact is clear: if we assign a zero prior probability for such evidence coming our way, as some scientists did in the case of ‘Oumuamua by invoking the principle “it’s never aliens,” we will indeed never find any. We will be like ostriches burying our heads in the sand.
In fact, this attitude may be one sign that our intelligence isn’t very impressive—that the human race as a whole suffers from the Dunning-Kruger effect, in which those with mediocre abilities insist that they’re unusually talented or smart.
How can our civilization mature? The same way kids do: by leaving home, going out into the neighborhood, meeting others and comparing notes with them. In other words, we can develop a balanced perspective on our current technological accomplishments by engaging in the search for extraterrestrial intelligence (SETI). Since our own technological development accelerates exponentially with an e-folding time of a few years, it is difficult to imagine what a much more advanced technology crafted by a civilization that had lived for a cosmic timescale—billions of such e-folding times—would look like.
As natural as this suggestion to search might seem, however it is evident that SETI faces a hostile mainstream culture in astronomy. The simple proposal to consider the possibility that ‘Oumumua is technological debris as an explanation for its unusual properties, for example was met with controversy on social media.
True, SETI carries non-scientific baggage related to unrealistic aspects of the science fiction literature and unsubstantiated reports about unidentified flying objects (UFOs)—something SETI researchers sometimes refer to as the “giggle factor.” But at the same time, it would be a strategic mistake for observers to restrict the interpretation of data from their telescopes and not search for “other kids in our neighborhood” just because of this baggage. The existence of extraterrestrial intelligence has nothing to do with the credibility of science fiction stories of UFO reports. The problem with adopting this wrong attitude is that it delays scientific progress. Grant applicants are frequently asked to forecast the scientific discoveries they will make if their application is approved—but by bracketing the range of possibilities in advance, we might never discover the unexpected. Instead we cultivate a scientific culture that tends to replicate what we already know.
History teaches us that this is a mistake. The search for extrasolar planets encountered mainstream resistance in its early days. Observing proposals to search for low-hanging fruits, such as “hot Jupiters”—which are easiest to detect—were rejected by conservative committees of telescope-time allocation that argued that such planets should not exist in nature based on what we know about the solar system. But discovery forged ahead as some observers dared to challenge this prejudice, demonstrating that hot Jupiters are abundant. There was 40-year delay, however, given that the first theoretical proposal to do such a search was made by Otto Struve as early as in 1952.
Hence, an obvious obstacle to identifying our neighbors is the tendency to limit our imagination to what we already know. But this should not necessarily remain the case in the future. What we imagine for extraterrestrial life should not be solely defined by the natural chemical and geological processes that took place spontaneously on Earth. We could, for example produce synthetic life in the laboratory under a broader range of conditions than those with which we are familiar. Metaphorically, we could bake new kinds of cakes using the same ingredients, expanding the book of recipes handed to us by Mother Earth.
Realizing that life can exist under new conditions will improve our forecasts for where to search for it in space and how to interpret our findings, in just the same way that the laws of physics—which were first revealed in laboratory experiments—allowed astrophysicists to study the universe billions of light years away.
An important survival skill in the company of unknown neighbors is to listen before speaking out. Given our sloppy behavior in transmitting signals to outer space without restraint, we can only hope that we have not become the laughingstock of our galactic neighborhood by now. But even if we have, we can still get our act together and do better in the future. In order to know how to behave, we should find out first who is on our street by searching with our best telescopes for unusual electromagnetic flashes, industrial pollution of planetary atmospheres, artificial light or heat, artificial space debris or something completely unexpected.
Fortunately, we possess instruments that are sensitive enough to find out not only whether we have neighbors but also whether they have noticed us already.