What civilization is that? You're presupposing that this civilization exists and that it is much older than we are.
When was that proven?
Has it been proven that there isn't? And why wouldn't there be? Has something been discovered that would prevent advanced lifeforms from existing longer than we have been here?
It hasn't been proven... yet... geeze what's with you? You think we have discovered
everything we will ever know? We might as well just stop all science then, because threed says we know everything we will ever know.
But
something has been interacting with humans for as long as we have been here. The question is what is it, and where did it come from? It might not be of extra terrestrial origin. But we have no answers on that.
So, on the basis of this assumed civilization we can now have confidence that just about any whacky idea will ultimately be possible. Why? Because they did it.
To assume we are the most advanced civilization in the Universe, you would have to assume we have been around the longest. And that we know everything. Do you really believe that? Has that been proven? No scientist will agree with you.
You know just about every new technology was thought to be "wacky". Did you know that when they made the first steam locomotives that scientists thought if they went over like 35 MPH that all the air would sucked from the train and everyone on board would die? That sounds pretty wacky, no? That was the state of science at that time. We learn new stuff all the time, or discover... often by accident.
Or how about the first atomic bombs igniting all of the hydrogen in the atmosphere? That's pretty wacky too.
They, who SETI is looking for. If there was no "they" why does SETI bother?
You know what? There are people in this world
you don't know. You never will know them. There are people in
your town that you will never know. You have no idea what they are doing
right now. So based on that fact, are you going to sit there and say you know that there are no beings in the Universe that might be more advanced than us? You can perceive all of the Universe? You know what they know and what they are doing?
Can you even justify that thinking?
And if you are assuming we are the only life in the universe, where did you get that idea? Has
that been proven? It certainly hasn't. And if we haven't discovered any other civilizations —yet— then does that prove we know EVERYTHING? Nope.
There is no reason to believe that Earth is anything special. We can observe here that life is prevalent, and will even exist in very inhospitable conditions. What we can extrapolate from that is that anywhere in the Universe where conditions are right, life is sure to exist. If it's been around long enough, it probably has become self aware and intelligent. Why would we, and not them?
So, can you prove there is no other life in the universe? No scientist would EVER say such a stupid thing. You also went that that old thinking in another post that life would be different from us because of different chemical makeup, etc., however, life would probably be carbon based because carbon is one of the most prevalent building blocks.
Carbon is the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen! So with all that carbon, hydrogen, helium, and oxygen, you are going to say that life on some other world wouldn't evolve around those common elements? OK buddy. And I have a bridge to sell you.
We can't prove everything because we don't know everything.