From Jacques Monod (Nobel Prize winner, biologist):
Man knows at last that he is alone in the universe's unfeeling immensity, out of which he emerged only by chance. His destiny is nowhere spelled out, nor is his duty. The kingdom above or the darkness below; it is for him to choose.
There is no purpose in life; Our duty as scientists is to consider that there is no mystery that is by definition impenetrable to analysis.
I think there's a big misunderstanding of the implications of "chance"!
If something has once in a billion chances to occure (life on a planet in our galaxy, for instance), and it does happen once.....Then it becomes a billion on a billion chances....because it happened!