Permutation City

Paul counted. The easiest thing in the world, he thought, when you're made of flesh, when you're made of matter, when the quarks and the electrons just do what comes naturally. Human beings were embodied, ultimately, in fields of fundamental particles -- incapable, surely, of being anything other than themselves. Copies were embodied in computer memories as vast sets of numbers. Numbers which certainly could be interpreted as describing a human body sitting in a room . . . but it was hard to see that meaning as intrinsic, as necessary, when tens of thousands of arbitrary choices had been made about the way in which the model had been coded. Is this my blood sugar here . . . or my testosterone level? Is this the firing rate of a motor neuron as I raise my right hand . . . or a signal coming in from my retina as I watch myself doing it? Anybody given access to the raw data, but unaware of the conventions, could spend a lifetime sifting through the numbers without deciphering what any of it meant.

And yet no Copy buried in the data itself -- ignorant of the details or not -- could have the slightest trouble making sense of it all in an instant.

Squeak. "Trial number three. Time resolution twenty milliseconds."

"One. Two. Three."

For time to pass for a Copy, the numbers which defined it had to change from moment to moment. Recomputed over and over again, a Copy was a sequence of snapshots, frames of a movie -- or frames of computer animation.

But . . . when, exactly, did these snapshots give rise to conscious thought? While they were being computed? Or in the brief interludes when they sat in the computer's memory, unchanging, doing nothing but representing one static instant of the Copy's life? When both stages were taking place a thousand times per subjective second, it hardly seemed to matter, but very soon --

Squeak. "Trial number four. Time resolution fifty milliseconds."

What am I? The data? The process that generates it? The relationships between the numbers?

All of the above?

"One hundred milliseconds."

"One. Two. Three."

Paul listened to his voice as he counted -- as if half expecting to begin to notice the encroachment of silence, to start perceiving the gaps in himself.

"Two hundred milliseconds."

A fifth of a second. "One. Two." Was he strobing in and out of existence now, at five subjective hertz? The crudest of celluloid movies had never flickered at this rate. "Three. Four." He waved his hand in front of his face; the motion looked perfectly smooth, perfectly normal. And of course it did; he wasn't watching from the outside. "Five. Six. Seven." A sudden, intense wave of nausea passed through him but he fought it down, and continued. "Eight. Nine. Ten."

The djinn reappeared and emitted a brief, solicitous squeak. "What's wrong? Do you want to stop for a while?"

"No, I'm fine." Paul glanced around the innocent, sun-dappled room, and laughed. How would Durham handle it if the control and the subject had just given two different replies? He tried to recall his plans for such a contingency, but couldn't remember them -- and didn't much care. It wasn't his problem any more.

Squeak. "Trial number seven. Time resolution five hundred milliseconds."

Paul counted -- and the truth was, he felt no different. A little uneasy, yes -- but factoring out any squeamishness, everything about his experience seemed to remain the same. And that made sense, at least in the long run -- because nothing was being omitted, in the long run. His model-of-a-brain was only being fully described at half-second (model time) intervals -- but each description still included the results of everything that "would have happened" in between. Every half-second, his brain was ending up in exactly the state it would have been in if nothing had been left out.

"One thousand milliseconds."

But . . . what was going on, in between? The equations controlling the model were far too complex to solve in a single step. In the process of calculating the solutions, vast arrays of partial results were being generated and discarded along the way. In a sense, these partial results implied -- even if they didn't directly represent -- events taking place within the gaps between successive complete descriptions. And when the whole model was arbitrary, who was to say that these implied events, buried a little more deeply in the torrent of data, were any "less real" than those which were directly described?

"Two thousand milliseconds."

"One. Two. Three. Four."