It appears many SETI speculations are inspired from very shaky logical assumptions.

1) It would be easy to detect microwaves or lasers beamed to us from nearby stars, and a lot of SETI programs are based on these assumptions. But there is no reason to believe ETIs would choose such a strategy unless they already knew we were here. I say we should look for broadcast beacons in the microwave spectrum.

2) We have no way of knowing that ETIs will be highly advanced compared to us. Sure, the arguments that they will be more advanced technologically are valid, and probably correct, but we have no way of knowing if Type III or even Type II civilizations are even possible, much less common. Just because we have had a technological explosion over the last few hundred years is no guarantee it will continue indefintely. ETI science may run into inevitable physical constraints preventing the open-ended progress of technology, or it may simply choose to stop when it it is safe, secure, comfortable and happy. I may be writing this on a PC, but I don't own an IPOD, a cell phone or an automatic transmission.

3) The same may be said for the longevity of civilizations. We haven't been around long enough as a species to expect multi-million year histories for our neighbors. Our technological history is much shorter than that.

4) ETIs are scarcer than hen's teeth, and hard to find. Even if we make the wildly optimistic assumption that there are a million SETI capable civilizations in our Galaxy right now, and they are all transmitting with some technology we could detect, we would still have to examine hundreds of thousands of stars to just have a 50-50 chance of stumbling on to one.

SETI success is like winning the lottery, not impossible, but highly unlikely. But I still buy a ticket every week...I can afford it, and you can't win if you don't play.