Quote from kut2k2:
Purpose is not observation, purpose guides observation.
What is a tree? Ask a botanist. I'm sure he or she could tell you some things you never imagined. That doesn't mean no human has or ever could have imagined them.
Scientific imagination is guided by reality. Religious imagination is guided by fear, wishful thinking, deceit and lust for power.
I believe purpose is a form of observation, because like forms of observation, it too filters reality.
This is what makes the scientific worldview such a powerful position, it's utilitarianism on a material level is unmatched. It filters very well for keeping human bodies alive.
But if you want to argue that everything is on a material level, then let's run with that. Human behavior looks more all the time like it can be explained as "nothing but" (science's favorite hobby) evolutionary neurochemistry, so now free will is on the table. Let's dispense with it, because it's been a thorn in my liberal toe for decades! : )