I realize that this is not exactly the forum for discussing complicated scientific issues, but I am surprised that you think so little of Brownlee and Ward. My understanding is that they are well respected in their fields. Not every astronomer, geologist, astrobiologist or astrophysicist may agree with their conclusions, but I doubt they would accuse Brownlee and Ward of pushing junk science. I agree that the field is open to speculation because the whole field of astrobiology is rather young, but if Rare Earth is junk science, then so is SETI and the Drake equation.
What I was trying to say, was that I do not believe in ET. However, I suspect there may be other life out there. In other words, I will let the evidence speak for itself as we continue to learn more about this universe.
Thanks for the explanation. That is a reasonable position to take since there is at this time no evidence whatsoever of extra-terrestial life. Since disproving the existence of extra-terrestial life is an impossible task, even if no extra-terrestial life exists, then the logical position to take is to keep an open mind.
Sigh. I was too harsh in my statement. What I am trying to convey is that people seem to latch onto each extreme in this debate. I decided to take a "wait and see" attitude. This is why I think SETI is so important. It is win win science. Either they are all over, or they are damn hard (or impossible because they don't exist/out of range time etc.) to detect. Both cases lend to further defining our place in this universe.