If an alien came down to earth and said " hey guys I am from another planet" would society disbelieve him because they have been programmed to respond in that way. This must be a hoax of somekind. I think the only way man would believe it would be if we were invaded in force…any thoughta??
It would be reacted to the way people always do. Some would believe right off the bat, and there would be varying degrees of skepticism from others. All he would have to do to prove himself is show some sort of technology there is no way humans could possess (which they could do by way of invasion if that was their intention).
I’m from the Crab Nebulae and we’ve been planning an invasion for 5000 years, i’m in the process of doing research and i realized that theres no intelligent life on earth worth enslaving. We already have better worker slaves and were in the process of finding a way to alter your aptmosphere to make it livabel for us. keep up with the industrialization and my work is done/
From the manner of their landing, their possessions, and their appearances, we’d know.
Haha, so if they landed in the Aquarius, looked like humans and had space suits and such as possessions, we’d know? 
Even if sentient aliens did exist and have had contact with us, I don’t think it would be a wise decision for the entire world to find out about the contact. My reasoning behind this is because of how the majority of the world is extremely faith-based, and for the religious to learn that their Supreme Being obviously did not covet them as being his best creations would cause disasterous complications.
If sentient aliens were shown to be real, the majority of the world’s religions could be proven false thereby destroying faith for millions and causing all hell to break loose.
You seem to imply the alien is some sort of human clone. If that’s what you mean, then of course they would doubt him. That’s human nature, not ‘programming’: outrageous claims require outrageous proof.
The obvious answer is:
Those who want Aliens to exist (generally atheists or stoned losers) will believe, those who don’t want Aliens to exist (generally religious types for whom Aliens pose a massive theological problem) will disbelieve. Just like anything else - people will interpret evidence according to their desires and passions.
OK Comp: My theory is that if aliens came and didn’t back-up any religions (as they’d be expected to by the latter) then the religious lot would “re-mould” themselves (again) to fit in to the new situation.
Those who want Aliens to exist (generally atheists or stoned losers) will believe, those who don’t want Aliens to exist (generally religious types for whom Aliens pose a massive theological problem) will disbelieve. Just like anything else - people will interpret evidence according to their desires and passions.
is it hard to imagine a God who got bored with us and made more of us?
I think it’s likely that Christianity would split into two branches, one Earth-centric that holds the aliens as demons, and the other evangelistic that would try to spread the gospel to this new race.
There are religions that posit the existence of other worlds, regardless. I don’t think that Eastern religions would face as many hurdles. Who knows, Islam is generally non-anthropomorphic (bans physical representation of God and prophets). It could very well be that the aliens would see this as a non-specist religion and themselves convert to Islam…
Or use them as a cover for the advance invasion of Earth, to sow confusion among the pathetic humanoids… much like the Mongol hoards would shout the Takbeer (Allahu akbar min kuli shae) before doing battle with Muslims.
Still, which Earth religion would be best from an extraterrestrial point of view is an interesting question IMO.