What of this possibility: Aliens and intelligent life-forms do exist at many levels of development, but no-one has discovered a way to travel the unimaginable distances of the universe. Even at near light speed travel, we can barely visit our own neighborhood in practical times.
What a silly thesis. I always find theories based on deep assumptions about extraterrestrial psychology bunk.<p>The beginnings of social rather than biological evolution on earth are fantastically recent on a geological scale. 10,000 years, give or take. And it's only been in the last 100 that anything that we've had anything that would be detectable from space.<p>On the sorts of timescale that the universe functions on, we simply have a tiny, tiny sample of what a technological society looks like in the one instance that we are aware of. It's such a recent thing that we can scarcely predict what it will look like in 1000 years, much less 100,000 or 1,000,000 and even 100,000 years would be a small sample to start generalizing upon.<p>In other words, we have no idea what we're looking for when we're looking for extraterrestrial intelligence. The odds of finding another society that is <i>exactly</i> in this first 100 year sliver we're at are vanishingly small.
Another possible explanation is that interstellar travel is impossible. Perhaps there's too much debris between star systems, and it's not possible to create materials strong enough to make a spaceship that can withstand a collision with the debris at the speeds required.<p>This doesn't quite explain the lack of communication signals. But if nobody can colonize the galaxy, then there would be less sources of signals.<p>BTW, the Wikipedia article on the Fermi Paradox (<a href="http://en.wikipedia.org/wiki/Fermi_paradox" rel="nofollow">http://en.wikipedia.org/wiki/Fermi_paradox</a>) does a very good job of detailing all the possible explanations.
"So evolving intelligence seems likely, given a propitious <i>habitat..."</i><p>I would argue the opposite. Human level intelligence isn't necessary for survival, so why should one assume that it's bound to be common when its not even the case on Earth now or in it's history? What percentage of life that has ever existed on earth could you consider to have an intelligence on par or better than ours? Obviously less that a hundredth of 1%. If evolution is the law of life, then I doubt that intelligent life in the universe is as common as is assumed
"Most bright alien species probably go extinct gradually, allocating more time and resources to their pleasures, and less to their children. They eventually die out when the game behind all games—the Game of Life—says “Game Over; you are out of lives and you forgot to reproduce.”"<p>It's not hard to imagine that happening - or more likely, the fraction of civilization that is capable of advancing society fails to reproduce, and the part that does reproduce isn't able to advance society.
It's Sunday-morning, and this topic is near and dear to me ( <a href="http://www.whattofix.com/blog/archives/2009/02/technology_is_h.php" rel="nofollow">http://www.whattofix.com/blog/archives/2009/02/technology_is...</a> ) -- so time for a rant<p>It's interesting that we generally suppose either we'll achieve some super-greatness as a species or die out in some horrible cataclysm.<p>How species-centric.<p>As the author notes, a long, slow, fizzle into nothingness seems much more highly probable than some dramatic ending.<p>As an exercise, what do the democracies and the people in them spend their money on? Not space exploration. Not even war -- the last "real" earth-shaking war was well over 50 years ago. Lately it's all been bush wars. We spend more and more energy and money on <i>ourselves</i>. It's not the species, it's the comfort of each individual.<p>What do people value and celebrate? Adventure and discovery by moving out into the Solar System? Heck, there's already a serious movement among scientists to eliminate or seriously limit human exploration. You see, we could contaminate the places we visit.<p>I could continue with examples, but it's seemed obvious to me for many years that, as far as moving towards the conquest of space or self-destruction, we're doing a lot of plugging in, turning on, and patting ourselves on the back about it. But not a lot of exploration. Not only do we not live in a culture of risk-taking exploration, we actively view our presence in the universe as an evil and do all we can to avoid making any kind of permanent mark at all.<p>I fear over the long term we will succeed at this.
In any system, there has to be a "first". The first bacterial spore, the first amoeba, the first star, the first planet.<p>Why is it so hard to think that we could be the first?<p>Also equally curious, why MUST they look different? Maybe they're already here and they look just like us.
I was listening to a talk on The Singularity, and it occurred to me that that might be a good explanation of the Fermi Paradox. (Which is similar to the author's idea, but a bit different.) Basically, our minds are likely to "merge" with the Internet, allowing us to tap into the internet as our personal and cultural memory storage system. But we cannot extend Internet access into outer space, due to latency and the inability to make copies of the entire Internet locally. So the future "us" would be tied to the planet in order to have access to our memories, which would be very difficult for us to live without.
It seems like a big leap to me to take the problems of our generation and extrapolate them to be a (literally) universal explanation for Fermi's Paradox. I have the same problem with the apocalyptic explanations. Just because humans have built enough nuclear weapons to destroy our civilization doesn't mean all other species in the universe would have the same inclination.
Maybe other intelligent beings in the universe didn't learn how to live with out fossil fuels, they overloaded the carrying capacity of their planets, global warming destroyed their environments and intelligent people stopped having children? The result would be that their complex civilizations crashed.<p>I think we have more important stuff to invest our intellects in than space exploration. All our current technology depends almost exclusively on cheap energy derived from fossil fuels. Human actions are damaging the complex processes that maintain live.<p>If we don't fix this problems I still think hedonistic technology is a better investment than space exploration. Well at least for the average folk it's not like we can send every human in to space.
I subscribe to the theory that our own bias as humans leads us to believe that human style intelligence is the pinacle of evolution throughout the universe. As one of the great old sci-fi writers said human intelligence has yet to be proven as a long term evolutionary advantage. It may be that less intelligent but more sustainable life is more typical. Look at the dolphins for example. They don't seem to have any interest in building radio transmitters or spaceships yet they are very intelligent. If this theory is true we can learn a major lesson: We have to become more sustainable creatures if we want to win the evolutionary contest over the long term.