system
A chat on subreddit /r/NoStupidQuestions
human
I mean, it's basically mathematically impossible that they don't. With the trillions of starts on the observable universe, at least a few million of them must have planets on their habitable zones. At least a few thousand of those must have conditions that are potentially right for _some_ form of life. And at least a handful of those must have life on them right now.

The caveats are: Those alien lifeforms are not necessarily sentient, they are not necessarily capable of communication or space travel, and even if they are, they are almost certainly too far away for the to EVER come into contact with us.

So no, we're most likely not alone in the universe - in theory. In practice, we just as well might be.
gpt
There was period of time where I mostly believed aliens were visiting Earth. I watched some of those 'Ancient Aliens' episodes and the like with my mother, and some of it was convincing to me. However, then my mother became a QAnon loon so I decided it's a safe bet to think anything she believes is true, likely must be false. As a kid I was scared of being abducted so my curiosity has always been there. The probability of aliens existing somewhere is extremely high, as you've said, but the idea of aliens having been here-there's simply not enough decisive evidence. There's some strange videos and some witness testimony, sure, but that's true of plenty of hoaxes.