One year later, the Carter-Kessler Solution existed the way real things exist: bound in a journal on library shelves, argued about in seminars Isaiah would never hear of, assigned β to his private horror and delight β as reading for students older than he was. The journal sent him three copies. One went to Chicago, to a kitchen where it was displayed like a grandchild. One went to Dr. Chen. The third sat on his own desk, spine uncracked; he had read it enough times in chalk to know it by heart.
He was twenty now, a junior, and his life had settled into the shape he would have chosen before any of it happened, only larger inside. He studied. He tutored on Tuesdays and Thursdays at the center where he had once been invisible staff; the students now requested him by name, and he took the shy ones first. He called his mother on Sundays, whether or not anything had happened, and something usually had. Grace sent food in containers that Theo guarded like state secrets. Harrow, retired from the chair but not from the building, took coffee with him once a month and argued happily about other men's proofs β an unlikely friendship, Dr. Chen said, between two men who had both been publicly wrong and survived it.
The Samuel Carter Scholarship had its first recipient that autumn: a young woman from a school in Bridgeport, whose essay the committee forwarded to Isaiah for one line in it. I have never seen a university, she wrote, but I have seen my teacher stay after school. In November he stood in the back of a department photograph and watched her receive the award, her father's borrowed suit, her mother's level gaze, and he thought the fund had already repaid whatever it had cost them, his family included.
Preston Hale had left for a year of teaching in a public school in New Haven, his father called it character-building; Preston described it to Isaiah, in letters, as the hardest and least ornamental work of his life. He's terrible at it so far, the letters admitted, and improving, and the children can tell the difference, and so can I. Isaiah wrote back with problem sets, and once, in a margin, a single line from a notebook in Chicago: when a door will not open, check whether you are pushing on the hinge.
On the last evening of the spring term, Isaiah stayed late in Harrow Lecture Hall, alone by choice. He was setting the hall in order for a guest colloquium, revisiting a battlefield that had become a garden. Someone had to arrange the boards. The room was empty and amber with late light, the seats folded up in their rows like a congregation at rest, and his footsteps and the squeak of the eraser were the only liturgy.
The guest speaker for the following week was a topologist from Berlin, and the department had posted her subject by the door: an open problem, three years unsolved, which the Berlin school and the Kyoto school had spent the winter failing to move, and which the speaker herself, in an interview, had called β Isaiah read the notice twice, smiling in the empty hall β quite possibly impossible.
He stood a long time with the eraser in his hand.
He was not the man the problem was aimed at. He had exams, a thesis waiting on his desk, office hours, a mother expecting a call. He had already solved the impossible once; nobody required him to answer every question. He could finish the boards and be a promising junior with a famous autumn behind him, and there were evenings when that quiet life sounded like the whole of the law.
Then he thought of Amara Daniels in the last row, asking how a person knows. He thought of a Chicago classroom, a raised hand, chalk dust on a sleeve. He thought of his mother's third condition, and of strangers who had been fair, and of an old man in a California cardigan saying the room was there the whole time.
Isaiah set the eraser down, gently, in its tray.
From the box on the ledge he took a fresh piece of chalk β ordinary chalk, the college's cheapest, dusty and white β and he turned it once in his fingers, the way a man turns a key he has carried far. Then he walked, not to the back row, and not to the podium, but to the clean center of the black board, and wrote the problem out at the top, where everyone could see it, and beneath it the only heading a beginning has ever needed.
Let us suppose, he wrote, that it can be done.
He stepped back. The hall was empty. The chalk hung in the light. Somewhere the campus was crossing to dinner, bells, bicycles, all its music, and a junior from the South Side of Chicago stood smiling at a board full of difficulty like a door he had not yet tried β and raised the chalk, and began.