Our Existance :
Think about this...
Lets take the first man and woman on this world.
They believed that the world was limitted to what they marked as their territory , limited either by physically unconquerable limits like a mountain or a river or sea or desert.
They believed that no life exists beyond that.
They had gods whose houses were in the same location as them..
They had sleepless nights worrying about whole of life as they getting ended by fire or flood or sandstorm..
Over our period of history we have basically remained the same...We may have transgressed some of these but the basic idea remain the same.
We are 100% sure that there are no aliens, even though we have only travelled to 1% of the universe known to us..
Our Gods are more generic now but still are localized to earth..
We all have sleepless nights about a nuclear holocaust wiping all of us clean out of existence..
But I have huuuge hopes for the future of my kind..
I believe that once man has conquered space then we will conquer time and probably evolve into Gods :)
At some point noone will believe that we were once limitted to earth and that we believed time being linear..
the same way we have no clues where the first of mankind originated from where we diversified from ...
:)
Death
God
Sex