wouldnt u agree that

microbes: common

complex life: between common and rare

non civilized animal life: rare(maybe 10 to 100 planets with animals in the galaxy)

civilizations: very rare

"It is known that there is an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the universe can be said to be zero. From this it follows that the population of the universe is also zero, and that any people you may meet from time to time are merely the product of a deranged imagination."

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Far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-eight million miles is an utterly insignificant little blue-green planet whose ape-descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea ...

i think animal life is more common than civilizations

well sure, the number of planets with intelligent life on them would only be a fraction of those with any life on them at all if you are talking about non-space faring species BUT what about if many planets have been colonised by an intelligent species, then there may be more planets with civilisations on them than animals but then again an intelligent species would probably take animals with them.

i think that non civilized animal life would be common, but a little more rare than microbes. i suspect there is complex life on europa(primitive complex life, like plankton, algae)

Although it is from the beloved HGTG, its wrong: If a only a fraction of all existing worlds is habitable, and even if it is a very, very small fraction - if the number of worlds in the universe is infinite, then the number of habitable worlds is also infinite. A millionth or a trillionth of infinity is still infinity.

I would agree on the starting posts basic assumption that life is rare, but I have doubts on the numbers - could be 10 to 100 planets with animals in the galaxy, but there could also be 10 to 100 million planets with animals - or only one. We don't know, but we can do educated guesses.

Oh yeah I had reread Hitchhikers lately, and I just had to quote it.

Your right, but in an absurd way I still think that it is just as reasonable to some of the theories out there.

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Far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-eight million miles is an utterly insignificant little blue-green planet whose ape-descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea ...

I agree with the hierarchy - I'd expect simple life will be more numerous than complex civilizations.

But beyond that we only currently have a sample of 1. Our planet has civilized life - if you grant we are civilized

The moon is dead. Mars is probably but not definitely dead. We have no evidence either way for the rest of the solar system. So beyond that it's pretty much wild speculation.

There are a lot of stars out there. They all might have some form of life, or none of them, or something in between. There really isn't enough information at the moment to be sure where reality lies on that scale.

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Spike
:)

instead of speculating, lets search!! who wants to join me in alien fishing on europa?

Ok, I'll bring the keg and the worms, you supply the transportation.

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At night the stars put on a show for free (Carole King)

ok sounds great. remember to bring ur space suit. and watch out for alien squid