The framing of this article reminds me of the relevant section of the letter to Menoeceus.
The question: "How do you look for alien life when you don't know what alien life might look like?"
Could be transposed as: "How do you look for gods when you don't know what gods might look like?"
And it seems to me that the only answer to that question is to start with a "definition" stating the essential attributes of the thing you think you are looking for. The article doesn't focus on addressing those in the case of "alien life," but it seems to me that what Epicurus is doing in regard to gods: his starting point is to define them as living beings, blessed, and imperishable, and saying that we reach that conclusion based on prolepses (which I think most of us presume relates to "images"). There's a lot more to say than that, but the point of this post is only to point out that you can't even discuss something without stating a clear picture of what you're talking about, and that problem is as apparent today (in this article) as it would have been to Epicurus.
QuoteWe have only one example of biology forming in the universe – life on Earth. But what if life can form in other ways? How do you look for alien life when you don’t know what alien life might look like?
These questions are preoccupying astrobiologists, who are scientists who look for life beyond Earth. Astrobiologists have attempted to come up with universal rules that govern the emergence of complex physical and biological systems both on Earth and beyond.
I’m an astronomer who has written extensively about astrobiology. Through my research, I’ve learned that the most abundant form of extraterrestrial life is likely to be microbial, since single cells can form more readily than large organisms. But just in case there’s advanced alien life out there, I’m on the international advisory council for the group designing messages to send to those civilizations.