Is the aim here to present a question that is understandable? Seems it ought to be.
The question is how to get from is to ought.
The idea is to start with function as the is part and some how make the move to the aim we ought to aim for.
Aiming has also evolved so has a function.
I think we need to understand the move from aimless functional moral behaviour, to aim based moral behaviour, which would be to get from is to ought.
Aim based behaviour is to do with increasing happiness and reducing harm, while purely functional behaviour is to do with survival.
Can we link aim to survival via the function of happiness and suffering?
Can we evolve from survival based function to aiming for happiness?
Is there some other way to look at this?
Or is it simply impossible to get from is to ought?