What sort of leading question is that? The question assumes there is a purpose. Is there?
The answer could be whatever you want it to be.
But science can't categorically say that there is - or isn't - a purpose. It can't answer the question. Since many people believe that there is a purpose to why they are here - after all, a lot of mental health seems to come down to 'purpose', not to mention a host of organisations and their 'mission statements' implying that purpose is a innate element of humanity, I would disagree that it is a leading question: rather, its one asked by thousands upon thousands of people every day.
Interesting that you say about a sense of purpose being very important for mental health. I do agree there. But I think it's a step too far to assume that therefore there actually is a purpose. I think the sense of purpose is allied to having a sufficient amount of serotonin in the brain - too little is a reminder that we haven't got the optimum conditions for personal equanimity. And not that we aren't fulfilling some sort of cosmic purpose. Every organism - you, and me, and them - fulfils its own purpose from birth to death and some of us do better than others, clearly.
I think we just are.
