You Don't Know That You Don't Know (and Other Such Puzzles)

This series is making my brain hurt... in a good way.

The Anosognosic's Dilemma: Something's Wrong but You'll Never Know What It Is
(Part 1)

DD: There have been many psychological studies that tell us what we see and what we hear is shaped by our preferences, our wishes, our fears, our desires and so forth. We literally see the world the way we want to see it. But the Dunning-Kruger effect suggests that there is a problem beyond that. Even if you are just the most honest, impartial person that you could be, you would still have a problem – namely, when your knowledge or expertise is imperfect, you really don't know it. Left to your own devices, you just don't know it. We're not very good at knowing what we don't know.

EM: Knowing what you don't know? Is this supposedly the hallmark of an intelligent person?

DD: That's absolutely right. It's knowing that there are things you don't know that you don't know. Donald Rumsfeld gave this speech about "unknown unknowns." It goes something like this: "There are things we know we know about terrorism. There are things we know we don't know. And there are things that are unknown unknowns. We don't know that we don't know." He got a lot of grief for that. And I thought, "That's the smartest and most modest thing I've heard in a year."

(Part 2)

In a brief communication presented to the Neurological Society of Paris, Joseph Babinski (1857-1932), a prominent French-Polish neurologist, former student of Charcot and contemporary of Freud, described two patients with "left severe hemiplegia" — a complete paralysis of the left side of the body — left side of the face, left side of the trunk, left leg, left foot. Plus, an extraordinary detail. These patients didn't know they were paralyzed. To describe their condition, Babinski coined the term anosognosia — taken from the Greek agnosia, lack of knowledge, and nosos, disease.

The contemplation of anosognosia leads to many questions about how the brain puts together a picture of reality and a conception of "the self." It also suggests that our conception of reality is malleable; that it is possible to not-know something that should be eminently knowable. It may also suggest that it is possible to know and not-know something at the same time. But additionally, it puts the question of how we "know" things at the heart of a neurological diagnosis, and raises questions about how we separate the physical from the mental.