How different could it get?

We ponder how to communicate with aliens.

At the prompting of one of his correspondents, our astronomer recently looked into the subject of communicating with extraterrestrial intelligences. [Extraterrestrial Languages, Daniel Oberhaus.]  Up to this point, his attitude toward extraterrestrial life in general has been that we do not have enough information to conclude anything at all.  At a meeting of the American Astronomical Society several years ago, he listened in on a (very popular) session devoted to the topic.  There was no definition for “life.”  There were some suggestions, most involving thermodynamics and all open to some objection.  No doubt ideas have been refined and extended since, but the definition remains elusive.  How would we know life if we saw it?

While we could probably identify a signal as being from an alien intelligence, mostly by ruling out any natural process, it’s by no means certain we could work out what it said.  A number of very able people have examined the reverse process, and have devised messages to be sent (some have gone out) to show there’s intelligent life on Earth.  However, these haven’t always been intelligible to other scientists and linguists.  Indeed, at a very basic level there is no general consensus on what language is and how it works.  Our astronomer found in his research that philosophers of mathematics do not agree on whether it is discovered or invented, and that has serious implications for using it as a basis for talking to aliens.

The main difficulty is that we have exactly one instance of life, and one of intelligent life.  (There are certainly intelligent animals!  Maybe “technically advanced” would be a better term.)  It’s extremely dangerous to generalize from a single example.

We would certainly recognize life, and intelligence, if it were very similar to ours.   Science Fiction is replete with near-humanoids piloting starships.  Indeed, there are many who argue that intelligent aliens must be similar to us, given that we are the product of an optimization process working over billions of years.  Others hold that anything vastly different would be by definition impossible for us to recognize.  We find these arguments no more than plausible.

Our feeling is that not enough thinking has been done about how life, and intelligence, might be accomplished in some entirely different way.  We suggest taking as a starting point how the world appears to animals with a very different array of senses from that of humans.  [See An Immense World, Ed Yong.]  Even as close a relative and long companion as the dog must experience a quite nonhuman world, built on smell and a different spectrum of sound.  What sort of arithmetic would an octopus invent?

We remain convinced that any conclusions about extraterrestrial life or intelligence are premature, and will remain so for a long time.  But by no means stop work on the project!  If nothing else, it has led to a much better understanding of the single example we have.