Is "Where there's smoke there's a fire," a good reason to believe intelligent beings have visited Earth?

[Blackrook]

I'm inclined to believe intelligent beings have not visited Earth because no undeniable evidence has been produced that they have.

However, there have been many thousands of unproven reports of flying vehicles over the past decades.

Does "Where there's smoke, there's a fire," good enough proof to believe?

 

[bluzman61]

I believe that because of the sheer size of the galaxies and number of stars there HAS to be intelligent life other than here on Earth. And I believe we HAVE been visited by other life forms. The numbers are just too large to ignore. I've never seen a UFO, but I want to believe they're out there.

 

[1srelluc]