(Sorry, reply was too long to fit in a single reply >.<)

First of all, if we are going to talk about "aiming for perfection," we never defined even what accounts for perfection. I didn't define it neither because I just gave it out as an example of why aiming for a goal that cannot be achieved might still be worth it.

For our context, I think the best definition for "perfection" is quite simple: "to not mess up. To not make mistakes." In the context of our life's goal, we should be able to phrase perfection as the state in which we don't regret our choices and we are happy with the outcomes of them. I understand that perfection can mean many things, and be a lot more rigorous for other areas like mathematics. But, for personal fulfillment, to "live a perfect life," I'd like to believe that simply not regretting our choices and feeling good about who we are should be enough.

Now with that defined, I must take on the crust of your argument: that we cannot measure our progress in such a model.

Your argument: We cannot objectively measure progress if the goal is unachievable. My counter-argument: That's not the right perspective to use on this issue.

The way to do things right: just look at each decision and reflect on how to do better. That's all there is to it.

I wonder if I actually treated the subject satisfactorily, I hope I did.