We haven't found signs or evidence because what we are looking for, or expecting to find, is just all wrong.
To understand the problem, first think about what we know of life. It is all around us. The Earth is covered in life, in the air, in the soil, in the sea, on the land. It is everywhere. From small microbes to giant whales and even bigger creatures that have long since died out. Life comes in so many forms, it might as well be an infinite variety. It remains well beyond human ability to catalog and classify and identify.
So we have a lesson staring us in the face: life comes in all shapes and sizes and kinds, and that's just this ONE planet. If this is typical, we can expect other planets might have similar diversity. When we look out into space, logically, we could look for this sort of world. It is, afterall, the only one we know. The only pattern.
But that's not what happens when we look for life out there. Oh hell no. All we look for is radio signals. Look at the Earth: teeming with life, crawling with it, covered in it. Only one has ever invented radio. And then only for a bit over 100 years. None of the other billions of fine creatures has ever bothered with radio. That we know of. Just one.
So when we look out into space, we aren't looking for life at all. We ARE looking for a copy of us, in this brief window when we had radio and made enough noise with it that it might be heard across short interstellar distances. But nobody really knows how far our signals get. And if you were on alien world doing what we do, listening for signals, but you did it 200 years ago, the Earth would be a silent and dead world. So that settles it: there is no life in space. Right?
This is basically what is being said now: we, in our infinite wisdom, have decided to look only for exactly what we are this very moment, and having not found that so far, we have unilaterally decided the universe is empty and nobody is home.
This is absolutely asinine. The stupidest mistake in human history: to expect to find ourselves out there, to LOOK only for that, using only primitive methods only really useful because it's all we've managed to invent, and we we do not find signs of life after just a few years looking, we declare the universe is dead.
Netcraft now confirms: the universe is dead and you will be too, soon.
That's pretty fucking arrogant.
"Pathetic Earthlings. Throwing your bodies out into the void, without the slightest inkling WHO or WHAT is out here. If you had known anything about the true nature of the universe, anything at all, you would have hidden from it in terror." -Dessler of Gamilas