OK. Should I use 6 or 20 sided dice?

Furthermore, SETI has beneficial side-effects, such as providing employment for professional astronomers, it’s good PR for science in general (how many other scientific research projects could have pulled off what SETIStars just managed?) , and it helps fund infrastructure that can be used for other scientific research.

There’s literally dozens of other arguments for why it isn’t likely that we’d find anything; I don’t have time to list them all. For example, my rough estimates of the number of stars in a searchable radius failed to account for the fact that those objects are all in different stages of evolution. Presumably, a star’s age and spectral type affect the chance of it harboring life, so it’s not unreasonable to assume that those stars do not all have an equal chance of harboring life.

In short, I still maintain that no useful information is obtained.

We have a whole lot of evidence built up over how life started, and we can rule out a load of mechanisms as we have developed reasonable ideas of what the Earth was like and the laws of chemistry. If we find in half the sky no signals from an alien civilization it means the following: if they exist they are rare and beyond our radio horizon at those frequencies. They aren’t transmitting in something we listen for if they aren’t. Just those two things tell you that a) intelligent life is likely rarer than we’d like and b) nobody out of millions of possibilities uses radio, so IF we accept the Copernican principle that we aren’t special, and that *someone* out there would discover radio (the laws of physics being the same and all) it puts a lot of lower and upper bounds on the frequency and technological development of civilizations — certainly it tells you that there IS something special about using radio.

That’s a lot right there and someone with real radio data could tell more. I picked half the sky because that covers enough to know with reasonable certainty if anyone remotely like us is out there since they are just as likely to be in one direction as another. Just like if you look for a certain phenomenon and didn’t see it searching half the sky you would say your chances of finding it in the other half are reduced. Either way your problem is that much easier to solve, right? The parameter space for technological civilizations is huge, but it isn’t infinite. There are some things we can say for sure would be evidence. Find nothing, and that means that maybe life doesn’t form as easily as we thought, or at a minimum that it doesn’t develop interstellar-visible technology that often.

As for searching for alien beacons, I figure that if you were going to set one up you want to make it sufficiently similar to a natural phenomenon that other people would be likely to have set up equipment that studies the right kind of thing, and you choose a natural phenomenon that requires rapid measurements to get better bandwidth. Forget the water hole, I reckon alien beacons are more likely to resemble millisecond pulsars…