Handshake

In the years since, when I have wanted to be unkind to myself, I go back to the warm end of that September and stand once more in the doorway of a stranger’s kitchen and watch my brother be right in the wrong way — right the way he was always right in those days, which cost him nothing at the time and everything afterward — and I remind myself that I was the elder by eleven minutes, and that I had spent every one of them, our whole lives long, learning to tell him no. I had been saving the word up. I understand that now. I was keeping it clean and dry against some later night when a no from me would be the only thing that mattered; and the night came, in December, on a bridge, and the no I finally spent was the wrong one, and it is the reason I am setting any of this down at all.

But that is the end of the story, and I have promised to keep things in their order, because he would have insisted on the order — the input first, then the fault, then the long patient stepping-through of an evening that will not run differently however many times you feed it back to itself — and because the beginning was a happy one, and there is so little happiness in this account that I cannot afford to hurry past the years when we still had all of it.

We were twins, and I will describe the nature of us the only way I ever found that held: we were one person who had been issued two bodies and, by some clerk’s mercy or cruelty, opposite instructions for what to do with them. Jonah was sent out into the world to believe it. I was kept back to check the arithmetic. He walked toward every bright thing on the horizon as though it had called him by name; I came a pace behind with the ledger, totting up what the bright thing would cost when the bill arrived, and loving him, and never once catching up. If you have read your Hesse you will know the arrangement — the one who goes down into the country of the senses and the one who stays in the cloister keeping the books — except that we were not two friends who found each other and were changed. We had been assigned each other before birth, in the dark, and had run a wire between us the first hour we were able, and were never afterward entirely certain where the one of us left off and the other began.

The night I have come back for was the first Friday of the fall term, in a rented house in Squirrel Hill where, one evening each year, the machine-learning students and the theory students drank from the same keg and were reminded why they kept apart the other three hundred and sixty-four. Jonah was a first-year master’s student and belonged there. I was a senior and did not; I was present, as I was present at most things that autumn, on my brother’s ticket, which everyone understood and no one said. Out on the porch a boy was reading aloud from the messages of the Mars rover, which had come down in August and had lately taken to narrating its own labors in the first person, and the porch lifted its cups to the little machine each time it spoke, because that was the temper of the year — we had set a device down on another world and taught it to say I, and it had just found, in a dry Martian streambed, the print of an ancient river, and this struck everyone as being precisely as marvelous as it was.

Inside, in the kitchen, my brother was defending Ray Kurzweil.

“Kurzweil,” a theory student was saying, in the voice a man saves for the name of the dog that bit him. “It is the year 2012, and you are standing in a kitchen defending Ray Kurzweil.”

He was; and I watched him take half a second to enjoy the coordinates, the way he enjoyed all indefensible positions, which he collected as other men collect grievances. My brother had a gift for being the most certain person in any room, and he wore the certainty lightly, the way the rich wear money — not as a thing he had earned that evening but as a climate he had always lived in and assumed you did too.

“I am not defending the man,” Jonah said. “I am defending some arithmetic he happens to be standing next to.”

“He graded his own predictions. Gave himself eighty-six percent. My undergraduates would commit crimes for that rubric.”

“Then grade him against anyone else. Name me one other soul who wrote down dated, checkable predictions in 1999 and had the nerve to stand there while the dates came due, one after another, and be counted. Everyone else in this business files their prophecies as directions for future work.” He pushed his glasses up with a single knuckle, which across a kitchen was correctly read as a man settling in. “You needn’t love the prophet. You are allowed to simply read the instruments.”

The theory student was a third-year, something to do with lattices, and he had the particular weariness of a man every one of whose cousins had read The Singularity Is Near and wished to discuss the uploading of their consciousness with him over the holidays. I did not hold the sneer against him. The sneer was a genre and not a person; you could argue with a genre until the keg ran dry and part friends. “The instruments,” he said. “The instruments have told us we are ten years away since 1956. This is the department — this is the city — where Herbert Simon stood up and said a computer would be the chess champion of the world inside a decade. He said ten years. It took forty.”

“And here you are,” Jonah said, “standing in the city where it came true, offering it as evidence that nothing does.”

Somebody by the refrigerator laughed into a cup. The theory student did what theory students do when they are losing, which is to change the coordinates. “Fine. Chess fell. Chess is a closed board and perfect information. The brain has a hundred trillion synapses and no documentation. Paul Allen wrote the thing up — there is a complexity brake. Each layer down into the machinery costs more than the last one paid back. The curve carries you until, all at once, it doesn’t.”

I had been watching this from across the room, over the heads of a knot of first-years, with something less than a third of my attention and rather more than I would have admitted — running my brother the way a good engineer runs a load average, not staring at the needle, exactly, but never quite looking away from it either. We had a signal for these occasions, older than either of us could date. Two eyebrows; four legal states. Both down meant go on, you’re on firm ground. The left alone meant source? The right alone meant ease off. Both together, held, meant abort — you are about to say the thing about 2029.

I sent him source? and watched it arrive, be read, be acknowledged, and be set gently aside, all in the space of a breath, which was well within his normal operating parameters.

Because I want to be honest, here, at the warm beginning, before honesty gets expensive: I could not make him wrong. God knows I tried. I wanted the whole Kurzweil business to fail the clean way, the way a perpetual-motion machine fails, on principle, before you even open the casing — and every time I went at it in good faith the numbers came back not false but merely unproven, which is a far more frightening word. The cat had unsettled me worst of all. That June, some group at Google had wired sixteen thousand processors together, turned them loose on ten million still frames plucked from the endless reel of the internet, and told them nothing — not what to find, not that there was anything to be found — and somewhere in that vast dreaming lattice a single unit had taught itself to wake for the faces of cats. No one had defined a cat for it. No one had told it that a cat was. Cats were merely present in the data, because the data was us, pointing our cameras at the things we love; and the machine, sifting, had found the thing we loved and made a place for it. I read the paper twice looking for the trick. There was no trick. There was only more computer than anyone had ever aimed at a question that soft, and an answer that no one’s theory had thought to ask for. I wanted my brother to be right the way one wants good weather on a journey. Wanting has never yet moved a forecast, and I declined to begin rounding at that late date.

The theory student had noticed me by now, and performed the small private despair of a man who watches the same face arrive twice.

“There are two of you,” he said, rechecking a premise.

“He’s the control group,” said Jonah.

“You believe any of this?” the man asked me. “Your brother has machines passing the Turing test while the rest of us are still paying down our loans.”

“No,” I said. “And I would like it on the record that the date is a fantasy.” I took the beer Jonah was already holding out to me without either of us looking, which was a protocol of its own. “Now — tell me what the brake is.”

“What?”

“Allen’s complexity brake. You invoked it. A brake is a mechanism. So name me the mechanism. Tell me what, precisely, gets harder in a fashion that compounds faster than the tools improve — because he never names one. It is two pages of this feels difficult to me, and you are holding it up beside a system that taught itself the idea of a cat, in three days, from nothing, this past summer. One of those things is a measurement. That cannot be right is not a measurement.”

“The burden isn’t on—“

“The burden,” I said, “is on whoever is doing the rounding. He rounds up; I’ve said so, it’s on the record, and he at least does it in daylight where a man can check his work. You are rounding to zero, which is the worse sin, because you are doing it in the voice people save for the word obviously. My brother’s number is a fantasy. But he arrived at it by reading the instruments. There is a difference between a poor reading and no reading at all, and only one of you tonight has bothered to take one.”

The kitchen had gone quiet enough that the porch came through — the rover, it seemed, had turned up its ancient riverbed, and the porch had resolved that this called for a toast. The theory student looked from the one of our faces to the other, found no seam in us he could get a blade into, and went to fetch a beer he did not want. Jonah raised his cup a quarter of an inch — acknowledged — and my eyebrows came down at last, and that was the whole of the exchange between us, and it was enough. We would both have been embarrassed to need more bandwidth than that.

We left a little before one and went downhill into Squirrel Hill with the party thinning behind us, past the shuttered pizza windows and the last bus of the night sighing somewhere over on Murray. September had stayed warm the way it sometimes will in that city, the streets holding the summer’s charge a few weeks past the equinox and spending it down slowly, and we walked through the last of it. I walked as though the light were always about to change. Jonah kept pace without hurrying, which is a different thing entirely, and the difference between those two gaits is, I have come to think, the whole difference between us.

Alone, we talked the way we had always talked, which a stranger would have needed a diagram to follow — each sentence launched by the one of us and audited in flight by the other, abandoned mid-clause the instant its destination was obvious, resumed three exchanges later from the far end as if no time had passed. It was not the finishing of each other’s sentences, which is a trick for lovers and confidence men. It was nearer to having no further use for the sentences at all — both directions of the wire live at once, no one waiting for the channel to clear.

“You were out at 2029,” I said, “before I even reached you.”

“I said it was conservative.”

“You said it to a room.”

“That is where the people were.”

We went a block on that, comfortably, two sets of footsteps and a single argument that neither of us needed to finish aloud, because it would keep. It had been keeping since we were nine. It would grow, before the autumn was out, into the argument of the whole season — but that was three weeks and one benchmark away, and the night was warm, and I did not know yet that we were spending the last of something.

And my brother walked, and felt the year beneath him like a floor he trusted. This was the thing he had long since given up trying to explain at parties, the article of faith that made it possible for him to lose every argument in a room and then sleep like a man who has money down on a sure thing: that the flat stretch of the curve and the steep stretch are the same curve. There is no boundary between them, no sign posted at the border, no night when the world announces its own turning. Everyone lives on the flat part, he believed, right up until the hour when no one does. And if you truly held that — held it in the spine and not merely in the mouth — the strange gift the belief made you was not urgency at all, as people supposed. It was patience. The doubling forgives you the early years; the doubling is the early years. A man could stroll, unhurried, through the flat decade of the only interesting century there had ever been, provided only that he knew which decade he was standing in. And my brother was twenty-one years old, and he was certain that he knew.

“You walk like we’ve already won,” I said, holding the corner for a light I would have crossed against, alone.

“We have,” Jonah said. “It simply hasn’t propagated yet.”