True, I can't really argue with the logic implied here, but finding water elsewhere might still not be a guarantee for life. Again, how inevitable is the development of life when for example water exists on a planet?

We do know that water must have been very important for life (on earth) to develop, so yeah finding water gives a planet a higher score on the likeliness-scale of finding life for sure.

Then again Mars has polar icecaps and frozen ice layers under it's surface, yet micro-organisms or fossils haven't been found yet. I'm not saying they won't find them there, but it would have quite some implications on how we will think about these questions.

Obviously it takes a huge amount of time and effort to research an entire planet like Mars, but it wouldn't surprise me either way. As in, yes the conditions seem to be good (although needless to say (at the moment) Mars is a much more hostile planet towards life than our earth), yet possibility doesn't imply an inevitability.

Why_do:I didnt disagree with you, in fact - I even agreed! Like I said: If there is no other life out there, the Unvierse is a MASSIVE waste of space.

Look at it from the brighter side; the less life out there, the less competition and more space for us to explore and colonize (aka pollute) eventually.

If there really turns out to be no life apart from our planet, (something that's not falsifiable considering the vast amount of planets on which life might exist... but still), then we could also decide to spread life ourselves.

throw a bunch of microbes into a puddle of water on a life sustainable planet and watch what happens, huh?

your great-great-great-great-great-great-great-great²³²-grandchildren could tell you xD

It's just more of the same: eyewitnesses and interpretation. After all, just because a recording says "I see an object", heck even if a recording has someone saying "I see a UFO", is not evidence, it's hearsay.



That's correct. But equally ridiculous is the idea that we can successfully "guess" what that "other" life could be. That's my point to that post: that since we only know of ONE sentiant lifeform, we should search on the parameters we KNOW lead to life, not parameters that we ASSUME could lead to some type of life. My thought experiment was just a quick "back of the envelope" examination of how one would go about, scientifically, trying to find these "other" lifes. As you can see, it's a lot more involved than looking for life like us.

"heck even if a recording has someone saying "I see a UFO", is not evidence, it's hearsay."

This are all Military officials that take care of the nations air space , these are not just random people , they are trained officers who can distinguish a ufo from say a fighter plane or the like. So , it's incredible that you would refute the arguments of government officials , the same people who'se opinions you seem to always hold in very high reguard , and only because their testimony disagrees with your believes.

"that since we only know of ONE sentiant lifeform, we should search on the parameters we KNOW lead to life"

Well we need to find a way to get to the other planets first , then we will see if there is life or there isnt.

LOL

Not so incredible when you consider I have never stated that I hold them in high opinion; that's your fantasy, not mine!

LOL

And anyway, there is nothing about being military or government that turns "hearsay" into "evidence". Just because President Jimmy Carter saw something he can't explain doesn't mean that this is "proof" of alien existance.



Really? What do you think that commercial pilots made of the f-117 stealth before it was public, hmm? Do you think that they reported it as "an airplane" even though they had no knowledge that such an airplane existed... or do you suppose that they reported it as a UFO? Exactly.

So all even the most vetern airman can say is "I saw something that I can't explain"... but the lack of an explanation is not the proof of aliens.




I don't think I've stated whether I believe that aliens exist or not, so how can you say this?

I thought it was evident that I made a "reduction to the absurd" to refute the claim that aliens have visited our earth


" one assumes a claim for the sake of argument and derives an absurd or ridiculous outcome, and then concludes that the original claim must have been wrong as it led to an absurd result "

I got started from scientific evidences ( the size of our galaxi)
I made some assumptions in favour of the claim but within the bounds of the physical laws ( the level of technology )
I got an absurd scenario

Honestly I thought it was so obvious

This is the point

a) spetroscopic analysis of even the most remote star systems demostrate that they are like our sun
No unknown elements has never been found in the thousands meteorits falling every year on our earth and coming from the deep space
ammino acids have been found in meteorits

b) As ChrisB said life can be based only on carbon
A complex organism must be made of different kind of tissues
These tissues must be reasonably stable but not that stable to allow the complex bio chemical process
Only carbon has this property

If you put a and b togheter it reasonable to assume that the aliens , if they exist, are like us , at least as far as their chemistry is concerned

Of course their shape, color ,dimensions , might be quite different

Beside also their planet must be like our earth for evident reasons