I laughed. “Perhaps… when I find out what the catch is.”

The rolling accelerated. “We know each other too well. Jack, we would have to rebuild you.”

There was no inflection in the artificial voice. The image of Earth rippled across Ghost skin.

I shivered.

“Ambassador, just give me one hint. You know I’m an inquisitive man.”

“A hint?”

“What are you trying to do, with your quagma?”

The rolling stopped. “You have heard of the Uncertainty Principle…”

“Of course.”

“We have violated it.”

After my meeting with the Ambassador I returned to our New Bronx apartment, poured myself a malt, slumped on my favorite couch, and called up Eve.

One wall melted. Eve was heartbreakingly real, at least when she didn’t move and the image stayed stable.

She looked around quickly, as if establishing where she was, then fixed me with an admonishing stare.

“You’re looking good,” I said, raising my glass at the wall.

She snorted, but pushed a hand through her grayed hair. “What do you want, Jack? You know this is bad for you.”

“I want you to tell me about the Uncertainty Principle.”

“Why?”

“I’ll explain later.”

She frowned. “The walls have plenty of popular science texts—”

“You know I can never understand a word of that stuff unless you explain it to me.”

“Lethe, Jack; that’s just sentimental—”

“Humor me. It’s important.”

She sighed and pulled at a stray lock of hair. “All right, damn it. But I’ll keep it brief; and when it’s over, that’s it.”

“It’s a deal.”

Now Eve changed, subtly, so that — without any obvious reworking of the image — she seemed younger, more comfortable on the couch. I guessed the wall was accessing an older part of her Notebooks. “To understand Heisenberg’s Uncertainty Principle,” she began, “you need to get a handle on quantum mechanics.”

According to the quantum philosophy, particles like electrons don’t exist as points of mass and charge. Instead each electron has a wave function which describes its position, velocity and other properties; it’s as if the electron is spread over a small volume of space delimited by the wave function.

“So where does the Uncertainty Principle come in?”

Eve twisted my ring around her finger. “You can reduce the spread of an electron’s position wave-volume — perhaps by inspecting it using very high frequency photons. But the catch is that the wave-volume associated with another variable — the electron’s momentum — expands enormously. And vice versa.

“So you can never know both the electron’s position and momentum; you can never reduce both wave-volumes to zero.”

“Okay. What’s the size of these volumes?”

“The scale is given by Planck’s constant. Which is a small number; one of the fundamental constants of physics. But in real terms — suppose you measured an electron’s position to within a billionth of an inch. Then the momentum uncertainty would be such that a second later you couldn’t be sure where the damn thing was to within a hundred miles.”

I nodded. “Then the principle is describing a fundamental fuzziness in reality—”

She waved her hand with exasperation. “Don’t talk like a cheap data desk, Jack. There’s nothing fuzzy about reality. The wave functions are the fundamental building blocks of the Universe; their governing wave equations are completely deterministic… well, never mind. The Uncertainty Principle is essentially an expression of the scale of those wave functions.”

“How does this relate to your work?”

She sighed and sat back in her couch. “It was at the heart of it, Jack.”

Eve had spent much of her working life trying to develop the principles of remote translation systems. Teleport beams, to you and me.

She said, “A translation device might work by scanning the position of every particle in an object. That information could be transferred somewhere else and a copy constructed of the original, exact down to the last electron.”

“But the Uncertainty Principle tells us that’s impossible.”

“Correct. But the Principle says nothing about transferring exact data about the wave functions themselves… and that was the approach I was working on. Also, in some way we still don’t fully understand, the quantum waves provide a connectivity to space. When two objects are once joined there is a sense in which they are forever linked, by quantum properties. It may be that unless full quantum functions are copied, remote translation is impossible.”

“That which God has joined, let no man put asunder.”

She looked at me suspiciously, as if expecting me to burst into tears. “Something like that. Jack, it may also be that consciousness is a quantum phenomenon. Without our defining quantum functions — without the anchorage they give us to reality, and to those around us — we are nothing.”

I set down my glass, stood and walked to the wall. Hesitantly she got up and walked closer to her side. “And this wave-function mapping was the technical barrier you could never breach.”

She shrugged. “Perhaps it’s just as well. Because if this was a perfect image of me, Jack, stored in this wall, you’d never leave this damn apartment.” She looked up at me, and I imagined her eyes softening. “Would you?”

“What would happen if you violated the Uncertainty Principle?”

The image wavered slightly; I imagined the wall frantically searching its datastores for a response. “You can’t. Jack, haven’t you understood a word I’ve said?”

“Just suppose.”

She frowned. “If the uncertainty limit were lowered somehow then greater data compression would be possible. Better data storage.”

“So sharper wall images. What else?”

“Faster, more compact computing devices.” The image crumbled for a sudden, shocking moment into a storm of cubical pixels. “Jack, this is right at the edge of what I left in my Notebooks.”

“Bear with me, please… it is important. How would you do it?”

She rubbed the bridge of her nose, as if her head was aching. “Assuming you’re talking about the Universe we’re living in — so the fundamental laws are the same — you’d have to find a way of reducing Planck’s constant, over some region of space. The interface between Planck-differentiated regions would be kind of interesting. But it’s impossible, of course.” She looked up at me, troubled. “Jack, I don’t like this. It makes me feel — odd.”

“I’m sorry.” Without thinking I reached for her, through the wall; but my hand passed through her arm with little resistance.

“Jack. Don’t.” She stepped back, out of my reach. “It only hurts you.”

“I have to go away.”

“What?”

“I’m to make an inspection of a Ghost experiment. They say I must be physically modified… I might not come back.”

“Well, why not,” she said. “Lethe, Jack, I’ve been dead three years. You’re getting morbid.” Then she raised both hands to her head and said indistinctly, “If Planck’s constant were taken to the ultimate, down to zero—”

“What? Eve, tell me.”

She looked at me through a hail of pixels, her eyes wide. “Space could shatter—”

She dissolved. The wall became a wall again.

So I was made a Ghost.

My brain and spinal cord were rolled up and moved into a cleaned-out chest cavity. My circulatory system was wrapped into a complex mass around the brain pan. The Ghosts built a new metabolic system, far more efficient than the old and capable of working off direct radiative input. New eyes, capable of working in spectral regions well beyond the human range, were bolted into my skull; and I was given Ghost “muscles” — a tiny antigravity drive and compact actuator motors.

At last I was dipped in something like hot mercury.

The Sink Ambassador came to see me while I was being reconstructed. Its voice was like a bird hovering in the darkness. “How do you feel?”