aliens or intelligient life may exist, but the question is whether we, or the human race are
'lucky' enough to encouter such intelligient lifeforms during their entire history of their race.
Earth was probably form 4.5 billion years ago, however human history only began 10-20 000 years ago.
It was argued that Mars could previously support life. Even if such life forms existed, human beings did not came to existent during that time to witness or even interact with such life.
just to quote the famous drake's equation in search of intelligent life
say there are
100000000000 stars in the milkway out of these
10000000000 stars are in the habitable zone out of these
1000000000 stars have planets, out of these
10000000 stars have earth-like planets
100000 of these planets develop life
1000 of these life supporting planets develop intelligient life
100 of these alien race develop interstellar communications and transport,
If we consider the duration from the beginning of the human race to the end of the human race.
99 of such alien races have either not advance their technologies to develop such communications and transport, or the race do exist during the time of human life
SO that leaves us with hypothetically 1 possible chance of encountering such aliens.
Nevertheless these are all assumptions.
Assumptions based on human logic.
On a side note, not relating to the above response, I do not see how religion was pulled into this.