In the book The Fragility of Goodness: Luck and Ethics in Greek Tragedy and Philosophy, Martha Nussbaum talks of "moral luck" and how someone who is considered good and leads a well-lived life may befall circumstances that are beyond their control. She discusses the role of Greek tragedy in particular, explaining how these ancient thinkers approached the very issue she covers and how they demonstrated on stage and in literature how human beings can enrich their sense of how human values are vulnerable to chance.

It appears that Martha Nussbaum is saying that goodness is dependent upon conflict; that being the relative safety of being in control juxtaposed with the being exposed to chance happenings that the agent has no hand in. She writes:

For it could hardly be denied that the ability to function as a citizen, the activities involved in various types of love and friendship, and even the activities associated with the major ethical virtues (courage, justice, and so on) require external conditions that the agent's goodness cannot by itself secure. By removing those conditions, events beyond our control may do harm, including ethical harm.

Unlike other proponents of moral philosophy who argue that morality is based merely on intent or on social duty, Nussbaum adds to that by indicating that opportunity is what could potentially make one good:

That is, events beyond our control may affect, for good or ill, not only our happiness or success or satisfaction, but also central ethical elements of our lives: whether we manage to act justly in public life, whether we are able to lovbe and care for another person, whether we get a chance to act courageously.

Note how she makes use of the phrases "whether we manage", "whether we are able to", and "whether we get a chance to". With such diction, she makes it clear that doing good or being good is not simply a product of the agent in question, rather a large part of it is deferred to chance. Goodness is not comprised solely of intent, but by the capability granted (or not granted) by outside forces.

She continues:

Thus even without raising the issue of luck's role in making us wise, or courageous, or just in the first place, we can see that it appears to have an important ethical role, in making us able or not so able to act virtuously, and thus lead ethically complete lives.

It makes sense, really. How can one be merely capable of good and not be good? One must have one to have the other.