in a normal context: nothing
when speaking with an intelligent person or whilst being drunk:
-Why is this question so important?
It isn't important at all, but it is an interresting subject.
-Is there an awnser to this question?
If there was, then life was creater with a reason, thus a creator (a god) exists, I don't believe in gods (other subject), thus life has no creator, thus life has no purpose.
-If we found an awnser, how could we be sure that it is the correct awnser.
see the second question, it is very difficult.
-Does the person next to you really exist?
Just kidding, this is a nice subject for when you are drunk. (the awnser is yes)