Amazing
In the New Yorker, Oliver Sacks has a new article about the case of Clive Wearing, who - due to a brain infection 20 years ago - now exhibits the "most devastating case of amnesia ever recorded." Despite his Memento-like short-term memory, Clive is sustained by 2 things: his ability to perform music, which he can accomplish so long as he is not trying to actively remember how, and his love for his wife, which sounds effusive and, well, desperate, since - though he sees her regularly - he always feels like he hasn't seen her in years and is lost in a sea just-waking consciousness. He doesn't know when he last saw her, and couldn't tell you what she looks like unless she's there with him, but he knows he loves her and knows who she is immediately when she arrives.

Desperate to hold on to something, to gain some purchase, Clive started to keep a journal, first on scraps of paper, then in a notebook. But his journal entries consisted, essentially, of the statements “I am awake” or “I am conscious,” entered again and again every few minutes. He would write: “2:10 P.M: This time properly awake. . . . 2:14 P.M: this time finally awake. . . . 2:35 P.M: this time completely awake,” along with negations of these statements: “At 9:40 P.M. I awoke for the first time, despite my previous claims.” This in turn was crossed out, followed by “I was fully conscious at 10:35 P.M., and awake for the first time in many, many weeks.” This in turn was cancelled out by the next entry.

This dreadful journal, almost void of any other content but these passionate assertions and denials, intending to affirm existence and continuity but forever contradicting them, was filled anew each day, and soon mounted to hundreds of almost identical pages. It was a terrifying and poignant testament to Clive’s mental state, his lostness, in the years that followed his amnesia—a state that Deborah, in Miller’s film, called “a never-ending agony.”
...
When I asked Deborah whether Clive knew about her memoir, she told me that she had shown it to him twice before, but that he had instantly forgotten. I had my own heavily annotated copy with me, and asked Deborah to show it to him again.

“You’ve written a book!” he cried, astonished. “Well done! Congratulations!” He peered at the cover. “All by you? Good heavens!” Excited, he jumped for joy. Deborah showed him the dedication page: “For my Clive.” “Dedicated to me?” He hugged her. This scene was repeated several times within a few minutes, with almost exactly the same astonishment, the same expressions of delight and joy each time.

Clive and Deborah are still very much in love with each other, despite his amnesia. (Indeed, Deborah’s book is subtitled “A Memoir of Love and Amnesia.”) He greeted her several times as if she had just arrived. It must be an extraordinary situation, I thought, both maddening and flattering, to be seen always as new, as a gift, a blessing.

What we don't know about the brain - it would seem - remains far more expansive than what we do know.