In this previous post I asked whether we could make something out of the distinction between well-being and human flourishing. Here I have a different suggestion of a way in which we could define this distinction.
Well-being and flourishing both concern events that it makes sense to hope for or fear. However,
flourishing = can be used to refer to what sis good for a human being qua human being,
well-being = can be used to refer to what is good for a human being, or makes her life a good one for her, simpliciter.
Let us unpack the expression "good for a human being qua human being".
The "good for a human being qua human being" relates to those things people have normally strong reasons to want, simply in virtue of the fact that they are human.
The concept of flourishing is different from the concept of well-being because it is an open question whether any aspect of human flourishing contributes to human well-being.
One might claim that knowledge is something people have strong reasons to want, in virtue of the fact that they are human, because being fully human involves the activity of the rational part of the soul, and rational activity involves the attempt to acquire true and justified beliefs. One might hold the former claim and hold without any logical contradiction that true and justified beliefs do not contribute to the well-being of a person, if not in virtue of contingent instrumental connections.
On the other hand, it is logically possible that there might be sources of well-being (things that make a person's life go a good one for that person) which are not sources of human flourishing. For example one might hold that pleasure is an aspect of well-being and deny, on the other hand, that it is something we have reasons to want in virtue of the fact that we are human.
Moreover, it is clear that this distinction presuppose that the predicate "being human" is understood as entailing the existence of some fact which is the "source" of normativity.
This is typically the view of perfectionists, those thinkers that regard human nature as a project that a human being might or might not fulfill, and that in some fundamental sense he or she ought to fulfill.
Hence if you are perfectionist, and you think that rational action is a fundamental attribute of human nature, you will think that people have, qua human beings, a reason to develop their ability to act rationally. (which precedes their desiring it)