Originally Posted by thorkil2

This discussion is interesting, but it seems to me, perhaps a little naive. First, the extreme diversity of life on this planet is indication enough that if life can get a foothold it will flourish to the maximum extent that the environment permits. In a Universe of the immensity of ours, the existence of other environments with some degree of hospitality to life is not even arguable. Among those, there will be some that are sufficiently hospitable to permit development of a kind of high social order that we might define as civilization (with variations that we cannot even begin to imagine). Some of those will be technologically based civilizations. It is not a given that old technology is super technology or that the potential for technological development is unlimited. It may be that aliens don't visit us because they face the same limits to interstellar travel that we do. It may simply prove to be impractical, and that's a state that you can hope for with all the fervor you can muster, because the alternative is potentially terrible. If you look at the nature of life on this earth and the way it relates to its own various parts, it would be stupidly naive to assume that old and/or technologically capable means benign. Life is competition by definition. The most incredibly stupid idea I believe I've ever encountered is the notion that we should ever want to let anything that might be out there with a capability of interstellar travel know that we are here, and where we are. We have no way of knowing the nature of what might be listening. It may not matter to an advanced technology whether the real estate is compatible or not. The fact of its being inhabited by another technologically capable life form might be sufficient to justify an effort at pre-emptive extermination (and if you don't believe that, look at our own history). Now, I'm not saying that's the only possible scenario, but it's a very real possibility, and because it's real, it's the possibility that should be uppermost in our consideration of the potential for contact, when in reality it is the most discounted. In the real world, for the most part, big fish eat little fish. If you don't know whether the water is full of sharks, diving in wearing a belt of fish heads may be the quickest way to find out, but not necessarily the smartest, unless you're the biggest shark in the pool. Rare? Common? It doesn't matter if they have travel capability and ever find out we are here. Once that cat's out of the bag, there's no putting it back.