We exist..... so its logical that other life exists in the universe. It far more likely that we are not the only life than it is to assume we ARE the only life.
We are only just exploring the laws of physics, we are children learning the first ABC's when it comes to that.
So for anyone to scoff and deny that advanced alien species can and do exist is simply illogical. If fact considering what we now know about the make up of the universe, to flatly say that only we exist as intelligent life is absurd indeed.
If you went back in time 500 years and took a person at random and brought them to a modern city they would assume most of our technology would be magic.... even technology that to us would appear mundane.
So imagine a civilisation perhaps 5000 or 10,000 years in advance of us. Mundane technology based on their advance knowledge of physics would appear to us to be impossible and fanciful.
So logically we can assume two things... we are not the only life in the universe. Anyone who assumes we are the ONLY life in the universe is probably the sort of person who believes in "god"
And we can also say that advanced technology that would allow passage through vast distances in space is also more than possible. Just because we do not currently understand the laws of physics in this field does not automatically make it impossible.
So those two simple facts make it very likely of alien visitation to earth at some point. The only real sticking point is wether it has happened yet, and wether its being kept secret knowingly or not.
As for me... I think its perfectly possible that we have made contact and that for whatever reason the goverments and agencies involved have kept it secret. I could cope with the facts of alien visitation and contact, but I know many people who would freak out and go doo-lally. So I can understand Why it would be kept secret.
As for this guy... he offers no proof so he cannot be taken at his word, the fact he was in the office he was does not automatically make him reliable.
I would like to think that there is a benevolent species out there who will help us when we are ready, but being the pessimist I always am I reckon we are more likely to be wiped out for our water and minerals