A student asked me, by email of all channels, “What is the purpose of humans on earth?” Being in a good mood, I cracked my knuckles and typed away. Here is what I answered.
My view is that the question “What is the purpose of humans on earth?” is ill-formed, or at any rate makes an un-argued-for presupposition that I would reject. That presupposition is that humans (in the plural) are the proper site of purpose. I do not see why a species should have a purpose, mainly because a species does not, as such, have experiences.
I (insert my name) feel things like pleasure and pain, I (insert my name) make plans and adopt/pursue goals. Humanity does neither of those things. So, once we get clearer about the sort of entity for whom questions of purpose matter, we get clearer on what a plausible answer might be.
The perspective on the world that I have is the only one I have. So, I alone have a stake in the events of my surroundings. On this humble (non-Godly) scale, it is obvious what I ought to do: enjoy good food, have sex, spend rewarding time with friends of my choosing, pursue a long-term career, learn and create new things, sip tea peacefully by the fire, and so on. Accordingly, the purpose of my life is to live and flourish, in a way that suits my distinctive nature as an individual rational animal. It is by that genuinely lived standard that matters of right and wrong are to be assessed.
By contrast, invoking “humans on earth” as one’s argumentative starting point is a move destined to veer into grandiose conclusions that are either utopian or pessimistic. I did not create the world’s problems, nor am I burdened with solving them. The world is not a giant hospital where you are born either a patient or a nurse.
There is no deep cosmic riddle for me to solve. Happiness is a proximate experiential state, so only misguided cultural constructs have put the near far. The philosophical task is to return where my body naturally wants to be, namely alive and well, without the guilt that seeking such individual peace somehow falls short of a genuine purpose.