Aliens Discovered! (Or not...)

[Leigha]

This raises one of the same philosophical issues that Leigha raised in the inference to the best explanation thread. If there are only a handful of competing hypotheses to explain some observations, and all the hypothesis but one seem to be eliminated, then the remaining one would be the best of that bunch. But that doesn't mean that it's the best in general, that it's the best of all possible explanations. The problem is that there may be all kinds of additional hypotheses that nobody has even considered that might better explain the observations.

So I'm inclined to think that these astronomers are probably reaching when they conclude that the periodic signals come from ETIs. They should be saying that the cause of the periodic signals is currently unknown. They can't be sure that the set of hypotheses that they considered and rejected was an exhaustive set that included all possible explanations for the signals.

Which raises the question, how can SETI researchers ever be sure that they have excluded all possible alternative explanations and really are detecting ETI's?

Agree very much with your explanation here, and it points to that phrase ''people see, what they want to see.'' (and thus, feel ''that'' is the ''best'' explanation)

[Syne]

The fact that they are only found in a very small fraction of stars within a narrow spectral range centered near the spectral type of the Sun is also in agreement with the ETI hypothesis.

The most likely explanation is that these stars, similar to the Sun, also have similar solar systems, at least in terms of elemental composition of planets and debris that periodically orbit through, and interfere with, the signals we observe. And like this article points out:

But don't get too excited: Borra and Trottier said that additional observations are needed to confirm this hypothesis, and outside astronomers are even more emphatic on this point. Indeed, a healthy dose of skepticism is warranted, said Seth Shostak, a senior astronomer at the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California.

For example, it seems unlikely that 234 separate alien societies would be sending out such similar signals more or less simultaneously, Shostak said.

"It would be like expecting us to send the same signals as the Abyssinians — it doesn't make a whole lot of sense," he told Space.com. "If I were a betting guy, I'd bet this is an artifact of the way they processed their data."