average answer.

He is understanding it, the paradox is, the earth is billions of years old,Our modern society is only a few hundred years old, but there should be civilizations out there who are millions of years old,its not that we should be "hearing' them ,but that they should be here..like flying around..they should have populated the galaxy by now..There should be many, many civilizations which are millions of years old..and they should be readily identifiable by the many signals filling our galazy....where the fuck are they?

But we still have not the slightest idea what the average lifespan of a technological civilization might be. It's also possible that there are predators out there, and the survivors only survive by keeping mum.

"Imagine yourself taking a stroll through Manhattan, somewhere north of 68th street, deep inside Central Park, late at night. It would be nice to meet someone friendly, but you know that the park is dangerous at night. That's when the monsters come out. There's always a strong undercurrent of drug dealings, muggings, and occasional homicides.

It is not easy to distinguish the good guys from the bad guys. They dress alike, and the weapons are concealed. The only difference is intent, and you can't read minds.

Stay in the dark long enough and you may hear an occasional distant shriek or blunder across a body.

How do you survive the night? The last thing you want to do is shout, "I'm here!" The next to last thing you want to do is reply to someone who shouts, "I'm a friend!"

What you would like to do is find a policeman, or get out of the park. But you don't want to make noise or move towards a light where you might be spotted, and it is difficult to find either a policeman or your way out without making yourself known. Your safest option is to hunker down and wait for daylight, then safely walk out.

There are, of course, a few obvious differences between Central Park and the universe.

There is no policeman.

There is no way out.

And the night never ends."

I think more likely, given the experience of life on Earth, the number of intelligences with the power to either traverse or communicate across interstellar distances is probably stupidly, stupidly small -- to the point that for all intents and purposes, we're pretty much it.

Between the discovery that we're not alone and the discovery that we are alone, I feel the second would be a much more profound driver of human accomplishment than the first.

To the religious, we are alone and we are it, and many are quite happy to drive nothing other than a stake through further human accomplishment by putting limits on those who would try. I think the discovery that we're alone would make that worse, but that's nothing to worry about because you can't prove that.... otherwise we'd have proof God doesn't exist. (Merry Christmas!)

There's another alternative that sits so uncomfortably with me, and that's if light speed is the limit and there's no circumventing it. The reason it doesn't sit well with me is that it means effectively intelligent life will always exist in isolation, the only hope being that civilisations pick up ancient transmissions from other civilisations. It is inevitable in my mind that there is life out there of some kind, but it doesn't necessarily mean that they'll be tangible to us. I feel like that would be a tragedy beyond shakespeare.. inevitable cosmic loneliness.

Well, first you must determine the average lifespan of a species...impossible until we survey the entire universe.
Then you must determine the average distance between populated planets.
Then you must determine the 'lifespan' of all possible transmission technologies (on average). (how long 'they' emit that kind of transmission)
Then you must determine the maximum range and speed of any transmissions, and what form those transmissions are in, which is what most of this video is about. Now we're looking in 2 small ranges of possible wave form communications for the first time. Subtract any with a maximum range lower than the distance from transmission to us (another unknowable).
Then you must determine how many ranges of not just wave form energy are we ignoring, but how many other forms of communication/emission/energy might there be that we aren't looking for or even conceiving their existence (another impossible question to answer)?
Only once ALL those (impossible) questions are answered (and I'm certain more that are unknown but important variables) can you do even preliminary calculations to determine how statistically likely it should really be to 'find' evidence of extra-planetary species/civilizations, and that number is almost definitely tiny by any standard.

To think they might be 'here' already, you must either assume they are a space fairing species (which would also indicate a species that 'raids' planets and moves on, not one that settles and/or trades, so lets hope not) or you must assume they have much faster than light travel, which if true, should mean one would expect to see aliens 'teleporting' everywhere, and likely some crazy looking evidence of the transportation method. If neither of these are true (space fairing or faster than light travel) you would not expect to ever hear or see them.
Since technology evolves, so do the types of transmissions that technology produces. To think that in the time frame a single type of transmission is used somewhere in the universe (+ travel time) we'll be searching for exactly that type of transmission form would be such an INSANELY unlikely coincidence that many would see it as proof of god (because it couldn't statistically happen naturally, like a babble fish).
What this means is, unless we become space fairing raiders ourselves, or find faster than light travel ourselves, we'll likely be alone forever, even if there is other intelligent life out there.
There's just too much to search in too many ways over too long a time span, like looking for a single protozoa in the entire ocean, when you don't know what it looks like or even what a protozoa is, and the protozoa only exists for one random week in your life time.
That's where I think they are....unfindable.

Here's an interesting take on it

http://www.economist.com/news/science-and-technology/21625662-history-life-universe-may-have-been-governed-frequency

That was definitely an interesting article.

I shudder to think of the eventual state of the Universe, if humans turn out to be one of the elder races (assuming we survive so long).

Great thread great comments !!!

He used to be such a happy man.

Let's say, for argument's sake, there are 1,500 advanced civilizations within 1000 light years of us.

If only 1 of those civilizations -ours- gives a shit about anything beyond their atmosphere, then there's your problem right there.

Once you add the chances of life, then intelligent life, then intelligent life that actually thinks it needs a way to talk to each other over long distances, THEN develops radio, only THEN can we hear them.

What if they just never got to broadcast signals? Wire and fibreoptic may have been just peachy for them. Or maybe they just got to cell phones before trying short wave...

Maybe they react to radio waves. Like the few people out there who get headaches -proven by blind tests- from being close to radio emitters.

Some great points here.

I think it should be obvious that our assumptions about the frequency of intelligent space faring life in this region of space at this particular Eon are way off. Hence no signals and no first contact. The Drake equation is full of shit, so there is no Fermi Paradox.

I feel like this is just unfair generalizing.

Not all religious people think this way. Even the Pope is ok with aliens (and evolution).