To what extent does incomplete knowledge hamper our ability to make judgments?

Donald Rumsfeld may have put it best:¹

There are known knowns: there are things we know that we know. There are known unknowns, that is to say there are things that we now know we don’t know. But there are also unknown unknowns: there are things we do not know we don’t know.

Rawls had this idea called the veil of ignorance.² Though the veil plays a nontrivial role in the way Rawls constructs his principles of justice (and correspondingly is the target of critique from all directions), I like applying a bastardized version of the veil when thinking about my own normative beliefs. It isn’t just a fancy way of saying to “treat others the way I would want to be treated”; it’s about considering how I would want to be treated if I were them and coming up with the principles that get me there. Ideally, this kind of thinking would divorce one’s moral and political beliefs from a myopic view of the world and hopefully make those beliefs more just. Unfortunately, it’s not that easy. Even if aligning principles with beliefs is simple,³ how exactly does one consider anything, much less a set of principles, from the standpoint of some other arbitrary individual?

I recently began watching The Wire, something I’ve been meaning to do for some time. A well-crafted show, The Wire gives a taste of what life is like in the Baltimore projects, humanizing drug dealers, enforcers, and robbers. Though my life experiences shed very little light on what it might be like to deal drugs in West Baltimore, if I properly adhere to the aforementioned veil requirement, a just consideration of current drug laws would require me to consider that first-person experience. In this case, The Wire might be able to help augment the dearth of experience I have on this subject, but is it enough? It’s unclear how one would know when a view of life is sufficiently robust to make reasonable judgments.

The problem gets even trickier when some life experiences are seemingly impervious to third-person analysis. In Levels of Life, Julian Barnes presents an unflinching account of the grief he experienced following the loss of his wife. Barnes writes:

We are bad at dealing with death, that banal, unique thing; we can no longer make it part of a wider pattern. And as E.M. Forster put it, “One death may explain itself, but it throws no light upon another.” So grief in turn becomes unimaginable: not just its length and depth, but its tone and texture, its deceptions and false dawns, its recidivism.

At times, it seems there is nothing that Barnes’s friends can do to alleviate the pain: those who refuse to talk about his wife out of respect piss him off, while those who do talk about his wife further his misery. Drawing upon one’s own personal experience or knowledge of grief serves no purpose; the basic act of deciding what to say to a friend in mourning is utterly impossible.

Ingrid Robeyns writes:

My worry is that this category of experiences, differences, practices, and other features of human life that we cannot understand without first-person experience, is much larger than we generally tend to assume. And that as a consequence, we believe that we know much more than we actually do know. And, as a further consequence, that we too often are wrong in our judgements of aspects of the lives of people significantly different than ourselves.

One might be able to recognize that judgments are more reasonable when done under the auspices of a veil requirement, but that isn’t nearly enough. These issues go all the way down: how do we know what we know? How do we know what we don’t know? How do we turn known unknowns into known knowns, and how do we know we’re doing that correctly?⁴ In the face of this mess, Robeyns is right to call for greater “epistemic humility” as a first-pass solution. Unsatisfying as that may be, perhaps that’s the best we can do.