I can't answer that yes or no.

I don't believe in aliens, if by believe in, you mean that I think aliens exist even though there is only unexplained phenomenon that might be explained by aliens existing, but no clear evidence. I need more evidence before I would say I think aliens exist.

An alien would be a sensible object. I'd like to sense it first before I concluded it was alien and it existed. It is because certain phenomenon are unexplained that we insert "aliens" as an explanation. But as a scientist, I leave it currently unexplained.

If I had to answer yes or no, I would say no, not until I get enough evidence to make my judgment. Do purple swans exist? I don't know, but so far, I'd say no if you forced me, because, they have never made a clear appearance to me.
 
My answer is certainly maybe though. I even saw something in the night sky I can't explain. A light like a shooting star crossed the sky, and then it changed direction on a dime and shot off at much higher speed and disappeared. I was with someone and they said "whoa, what was that!?" so I know I saw something.

But I have no idea what I saw.

To make this philosophy, if there are sentient beings that are not human, I do believe they will be a lot like us - have math and logic, have language, have physics, have philosophy, and probably similar laws and proofs, at least at the highest levels. They would have to admit that we humans, like them, understand the notion of appearance distinct from reality, and so the notion of truth. They would have a notion of good.

I do believe we humans are not simply making all of this philosophy up. We are making it up, but any sentient being would be forced to play the same game we play. So we aren't just making it up. We are finding the real rules of the road for any traveler of space and time. They would understand subject/object distinctions, being and non-being. They would have a name for "time" and "space" and "nothing" and "infinite". My notion of "nothing" would include the exact the same content as the alien's notion.

But who knows. Hope we get to figure this one out, and they don't eat us.

What precisely do you mean by "aliens"?

any life outside of earth that did not originate on earth.

Yes – a very high probability wherever there is liquid water, etc. :up:

On some of those zillions of planets orbiting all those bejillions of suns, of course there must be other life. And whatever form it takes, wherever it happens, that life would be alien to us. Moreover, I expect many of those aliens to be intelligent and organized. I don't believe it's possible for this to be a one-off or for us to be that God-blessed unique.

Some sort of life must exist out there somewhere, it is almost impossible that this is the only place that life exits.

But there are probably limited numbers with the compatibilities to travel here to visit or dominate us.

life started exactly once in 4 billion years on earth. That heavily implies it’s a one off event.

How do you know it only started once on this planet? Even if it was just the once on this one planet, having begun, it thrived, proliferated, evolved and filled every possible ecological niche of this planet. If your contention is that there was time for more life to start on Earth, that's unlikely, since what was already here didn't tolerate competition from any upstarts: any new life form would be consumed.

Every planet out there capable of supporting life only needs one moment of the right conditions to converge to start its own version of life. Nothing about 4 billion years suggests otherwise.

:up: :up:

how do you know that life would out compete any new life arising? We would have evidence for that in the fossil record if it were true.

Being that there are billions of billions of billions of billions of stars in the observable universe alone, and that let's say, one-millionth of those stars have orbiting Earth-like planets, and one thousandth of those planets may sustain life in one way or another, we will still have billions of billions of billions of planets where life may evolve in the observable universe alone. So in our current knowledge of the universe, there is likely extraterrestrial life out there.
Though it is possible that in our galaxy Earth is unique.

how do you know that life would out compete any new life arising? — an-salad

I don't. It's a more reasonable speculation, according to what we know of life as it is, than to think existing species would meekly stand aside and watch a new genesis grow.

We would have evidence for that in the fossil record if it were true.

We do. The fossil record is not one of sweet tolerance and co-existence, but waves of proliferation, extinction, change, explosion, diversification and die-off.
Just how does this particular quibble support your uniqueness conceit theory ?

we would have records of life unrelated to other life in the fossil record if that happened

Why should we? It would all have to be made of the same components. Carbon, oxygen, nitrogen and hydrogen can only combine in a finite variety of configurations. How do you figure any life forms that arise in similar environments and conditions would look "unrelated" in a fossil record - especially as it would have required some considerable development to leave any fossil trace?
And yet again:
Just how does this particular quibble support your uniqueness conceit?