Q: What is the purpose of life?
A: What is the purpose of a new born baby?
Q: But you must have a definite conception of what you want to achieve in life.
A: My goal is to become human, and work for the survival of wisdom.
Q: Why do you strive for the survival of wisdom? What value does it have?
A: Why does a flower grow? What value does it have?
Q: Do things have a purpose, or a reason for existence?
A: Things do not have "reasons", but they do have causes. Things happen by necessity, not by purpose. "Reasons" are mental constructions.