Do aliens exist?

[Doubting Thomas]

I will say that it's likely, but until life elsewhere is discovered, we'll just have to say a big "We don't know."

I don't believe, however, that aliens are visiting us in flying saucers and giving people anal probes. The same vast distances which cause a problem for us to visit other planets or other solar systems would be same problem for aliens. And the "wormhole" idea is just science fiction. But I always thought the idea of aliens secretly visiting us in spacecraft with a bunch of bright colored lights all over it is silly.

I have noticed, though, that whenever someone talks about alien life they always assume that aliens will be far more technologically advanced than we are. But how do we know they're not living like cavemen? Or, perhaps they reached a certain level of advancement, but then they invented religion which has held them there for eons? Or they could be technologically advanced, but only, say, to the level where we were in the 1950's or so, where space travel was only a dream and seen in science fiction movies.

I think the best argument for intelligent life elsewhere in the universe is that none of it has attempted to contact us.