"Not the other members of staff." I shrug. "Does it bother you?"
"Yes. But I don't know why."
"I'll stop doing it. I really am sorry, you know."
We both carry on turning the earth. I find an earthworm, which I carefully pick up and move somewhere safer. Lura watches me do this, but I have no idea what she's thinking.
"What did you find out about me when you were in Saul's head?"
"Hardly anything," I say. "I know you slept together in Germany—that's the only intimate detail I do know. There were obviously a lot more details about the two of you, but remember I was just trying to find out where he was, not how he felt about anything, so I followed one set of memories rather than another."
"Hm."
"I really am sorry. Look, you're welcome to go into my head if you want, anytime you want. I've got some pretty sordid stuff in there, including some details I left out of my 'story so far' I told you the other night."
"It's OK. But thanks," she says, and goes back to turning over the reddish earth with her trowel. What I've said seems to have made no difference at all.
But then she smiles.
"I always like to garden when I've got something to turn over in my mind," she says. "It's repetitive and relaxing, don't you think?"
My God. Has she actually just started a conversation with me?
"Yes," I say. "It is, actually."
"Saul has to do everything in a 'Zen' way, at the moment. So he puts his whole being into turning the earth, if that's what he's doing. Not that he ever does the garden. But sometimes when he paints a fence, or wires a plug, you can see him doing it: giving up himself to the activity and not using it as an excuse just to think about something else."
I wonder what she's turning over in her mind. Probably how she's going to ask me to leave. I don't quite know what to say next. But I don't want the conversation to end, either. For the first time since I've been here I don't feel as though Lura despises me.
"Oh, there was another answerphone message earlier," I say.
"Ah. The writer. Again."
"The writer?"
"Yes. This is the problem I'm turning over in my mind." She sighs, and there's a long pause. "Saul tells me you know a lot about thought experiments."
"Yes," I say. "I am—or maybe I should say 'was'—doing my Ph.D. on thought experiments."
"Hm. Would you say that a story can be a thought experiment?"
"Oh yes," I say immediately. "I'd say all thought experiments are stories."
"That's interesting. Why?"
"Well, because all thought experiments take the form of a narrative. Well, the ones I understand do." I realize I'm talking to a real scientist and suddenly see I need a disclaimer. "I'm sure you can tell me about thought experiments that aren't stories. But..."
She's frowning. "No. I like the idea of thought experiments being stories. I suppose if they're not stories then they're actually hard science and not thought experiments at all. Einstein's trains ... Schrödinger's cat. Hmm."
"Yeah—they're two that I'm studying quite closely."
"Well, we'll have to talk properly about them at some point. But, for now, you agree that a thought experiment could be a story?"
"Yes, definitely. Why?"
"How about if I ran a thought experiment by you? It's concerned with the Troposphere, and although it does exist as a story—with characters and so on—I haven't actually seen the story, so I'll just tell it as a kind of story but with no characters, if that makes any sense."
It doesn't really, but I nod. "Go on. I'm intrigued."
"What have you already worked out about the Troposphere?" she says. "And I mean the very basics."
"Um," I say. "It's a place made of language."
"More specifically?"
"Well, thought," I say. "And it's made in metaphor and..."
"Thought," she repeats. "Excellent. Yes. It's a place made out of thought. So we might want to pose the question: What is thought? Would you agree?"
"Yes."
"And our experience of the Troposphere shows us that thoughts aren't just invisible, imaginary nothings. They are inscribed as soon as they happen, and in that sense they become entities. Would you agree with that?"
"Yes. I'd agree with that."
We're still turning the earth, although this bit is really done now.
"Right. So we want to consider this idea that thoughts have substance."
I remember something from Apollo Smintheus's first document.
"Thought is matter, perhaps," I say.
"Yes! Exactly. But it's hard to visualize how thoughts are matter exactly."
"Yes. I must admit that I haven't been able to see it."
Although the sky is still completely blue, a couple of raindrops fall on my face. I look up to see where they're coming from, but there aren't any clouds.
Lura smiles at me. "All right," she says. "Here's the story. The thought experiment. What would you think of the following scenario? Imagine a computer, with a vast hard drive memory. There's a program running on the computer—maybe a little like a game, with characters and locations. Now, the little characters in this program are written in binary code. Say they're part of a simulation game. You must have seen the type of thing I mean, where you create, say, a little town for them to live in and then the software generates effects like rain and droughts and wars?"
"Yeah. I know the kind of thing you mean," I say.
"All right, well, this next bit takes a leap of faith. What do you know about artificial intelligence?"
"I know that Samuel Butler was concerned that machines could become conscious as easily as humans did," I say. "That machine consciousness is as inevitable as human consciousness."
"This is interesting. Go on."
"He argued that consciousness is just another part of evolution. It's a random mutation that could happen to anything. And after all, machines are made out of the same stuff we're made out of ... And we feed machines all the time. We feed them fuel, and language..."
"Yes!" She taps the soil with her trowel. "Good. But don't jump ahead."
Since I don't know where this is going I'm not sure how I can stop myself jumping ahead by accident. But I turn over some more earth and just say, "OK, sorry. Go on."
"Imagine that some mutation happens in our computer simulation. The little characters become conscious. Now. What would their thoughts be made of?"
I visualize my laptop sitting on a desk, with this game playing out on it. I imagine what it would be like to be one of these digital, binary characters. How many dimensions would you be aware of? How would you interact with other characters? I think about what this world is made of—basically zeroes and ones—and then I realize that in this little world everything would be zeroes and ones. The little characters may not be able to see them, but everything, including their thought, would be made from the same thing.
"Their thoughts would be made from the same code their world is made from," I say to Lura. "Zeroes and ones."
"Yes, very good. Yes—if it was a contemporary silicon machine, which would obviously be coded in binary."
"So it would be up quarks and down quarks, if it was a quantum computer."
Now she smiles. "You do know something about science," she says. "Except you're not quite right. Up and down quarks are still a binary system. The whole point of quantum computing is that the quarks can be in a combination of different states, and can therefore carry out more than one calculation at once."
But I'm already feeling sick, because I think I know where this is going.
"Now tell me," she says. "The grass and trees in our binary world. What are they made from?"
"Zeroes and ones," I say.
"And the houses, and the water and the air?"
"Zeroes and ones."
"And what happens to thought in this world once it has happened? Does it disappear?"
"It gets stored on the hard drive." I pause, thinking about te
mporary caches and the difference between RAM and ROM. "Does it?"
"Yes. It's information rendered in zeroes and ones just like everything else in this world. So would you agree that the hard drive is expanding at the rate that these beings think?"
I think about this. I've stopped using the trowel, so I put it down and sit back on the tarpaulin. Another couple of raindrops fall from nowhere: the same invisible cloud in the sky.
"Yes?" I say. "I'm not sure about this one. It sounds like it's potentially a trick question."
"Yes. It is. The hard drive itself doesn't expand, or change, or gain mass, or anything like that. But the information on it changes. It gets written on all the time. If you thought the hard drive was just empty space to be written on, you'd think it was expanding. But if you realized that it was just information being coded so it made sense—but not more or less information altogether—then you wouldn't think it was expanding. You might argue that there is no empty space in this scenario."
"OK."
"So. What do you think so far?"
"I think I feel a bit sick."
"OK. But why?"
"Because what you say makes perfect sense. The Troposphere is like a hard drive that we wouldn't normally have access to although in theory we could, as it's on the same machine ... And. Oh shit. We're living in a computer simulation. Is that what you're saying?"
"Ah," she says. "Good. That's interesting. No. I don't believe we are living in a computer simulation. The computer is a metaphor."
"A metaphor for?"
"That's what I want you to think about for a while," she says. "You've already helped me with my conundrum about the writer. But now I want you to think about something else. In this computer simulation, if thought and matter are made of the same thing, then how is matter made?"
The rain starts coming down more heavily now, even though there are still no clouds. Lura gets up.
"Maybe it's this famous storm," she says. "Let's go in."
Once we're inside Lura goes off towards her study.
"Think about it," she says to me again.
So I do. I sit on my bed and I think it all through. I spend all day doing it: playing the thought experiment to the end with a little more detail each time. If thought and matter are the same thing, then how is matter made? I think about matter, and what it is—just quarks and electrons—and I wonder how quarks and electrons are really different from zeroes and ones. In both of these possible worlds they "make matter" in the same way. Or, at least, they are matter: The rest is just shape and perception. Or perhaps shape and perception are the same thing. The universe, just like the computer world, comprises the same amount of matter. Quarks and electrons can be combined to form anything you like in the physical world: a seed, a tree, carbon. And then things rot and get made again, out of the same stuff.
In the computer world you could make something from zeroes and ones—a pornographic picture, for example—and then you could overwrite it with something else entirely if you had the right software that let you fiddle around with the memory on the level of zeroes and ones. You could make it look as though the image had never been there: that it was unwritten space all along, or a document about a tree. But you might leave a trace; fossils, for instance, are traces. Quarks and electrons frozen in time, refusing to be broken down and made into something else.
So, how is matter made?
Later, over a dinner of mushrooms on toast, the discussion starts again.
"I told Ariel about my book," Lura says to Burlem. "Or at least that thought experiment about the computer."
"That's the only bit I really understand," he says. Then, to me: "The rest is mostly maths."
"I haven't answered your question yet," I say to Lura. "'How is matter made?'"
Burlem laughs. "That's a nice conundrum to set someone for a rainy afternoon."
The sky has been darkening all day, and by three o'clock I wasn't sure what was happening outside: whether it was night, or the storm. At about five o'clock I was making a coffee and I saw Burlem trying to entice Planck out of the door. But all the dog would do was reverse back into the house. It was the quickest way to get out of the rain, but it looked faintly comical.
"I didn't expect you to," Lura says, with a friendly smile.
"But I get that quarks and electrons are just like zeroes and ones," I say. "And it seems obvious to me now that thought is matter..." Except I have a bit of a problem with this. If thought is matter, then everything is real. But I thought that nothing was real. Derrida's difference; Baudrillard's simulacra. If thought is matter, then everything becomes real. But if you turn the equation around—if matter is actually thought—then nothing is real. Can both of these ideas be true at the same time? Can this equation work in the same way as 'energy equals mass'?"
"Although thought doesn't make more matter," Lura says, "neither thought nor matter can come from nowhere."
"No. I can see that, I think. But thought kind of ... shapes..."
"Encodes," Lura says. "Thought encodes matter."
"Which means what?" I take a sip of red wine and my hand trembles.
"When you think, you potentially change things."
I think about this, and everything she's said. I imagine the little binary people in their world where all the stuff they see around them, and all their thoughts, are made of the same thing. Presumably in this world you could create things just by thinking them. There'd be no difference between a thought of rain and rain itself. But surely that doesn't follow in this world.
"Are you saying that if I think a tree, I can make a tree?" I say to Lura, unconvinced.
"Not in this world," she says.
"But in the computer world? In the thought experiment?"
"Sort of," she says. She looks at Burlem. "She has a very good knack for simplification," she says.
"Not a skill you really need in an English department," he says. "But yes."
"Why 'sort of'?" I ask Lura. "Why can I only sort of make a tree by thinking it if I'm one of these beings?"
"Because it depends on what sort of code you're thinking in," she says. "Whether you can think in machine code or just within the software program."
"I'm having trouble with this," I say, frowning.
I can barely taste my food. I'm so aware that this is reality we're talking about: This is the room I'm in, and the chair I'm sitting on, and my mind and my dreams and everything that makes me exist. I have the bizarre sensation that if I get any of these questions wrong, things will start melting around me: that the existence of everything depends on this.
And then I think, Don't be stupid: It's just a theory.
But I've seen the evidence for it. I've been in the Troposphere.
But the Troposphere could mean anything, surely?
"Trouble?" Burlem says, laughing. "Oh, join the club."
"I mean, it's as though the whole world is turning, I don't know..."
"Upside down?" Lura says.
"Yeah. But in more dimensions than just four. I can't..." What do I want to say? I'm not sure. "So what is machine code?" I ask. "And why can't I think trees?"
She takes a sip of wine. "My whole book is about what this 'machine code' possibly is. I'm not sure myself yet. I've got my hypothesis that it exists, but I'm still looking for the mathematics that completely explains it ... I think I'm probably seventy-five percent there." She puts her wine down. "You know, of course, that in the real world you can't make something just by thinking it. You can't create a ten-pound note when you're poor, or a sandwich when you're hungry. The mind just can't do that."
"It's a shame," Burlem says.
"But we also know—or we've agreed for the time being—that thought is matter. Thought is encoded; thought never goes away. Everyone's thoughts exist in another dimension, which we are experiencing as the Troposphere."
"Yes," I say, putting my fork down.
"We know thought is matter because it is happening in a closed system, in which e
verything is made from matter. Just like in the computer program in our thought experiment. There's nothing in there that isn't written in code, because, well, you just can't have something on a computer that isn't written in code. Anything outside the system by definition couldn't exist within it."
I imagine my laptop again, and the little binary beings in their little world. I'm outside of their program—their world—as is the plastic case that holds the screen and the hard drive, and the computer screen itself, and the desk the laptop sits on, and the whole of this world. And the beings would never, ever be aware of those things. Even if we did decide to tell them about it—we'd have to put it into their world using their code. And then, somehow, it would be part of their world.
"But we also know that thought doesn't create more matter," Lura says.
"I can see that," I say. "The computer beings couldn't just will more RAM into existence, for example."
"Good," Lura says. "But the matter that is there can be manipulated."
Where have I heard the term "spoon-bending" recently? This is what comes into my mind, but I don't say anything. I'm not even sure spoon-bending really happens, and there don't seem to be any examples of people thinking of a goldfish, for example, and making one appear. Magicians who seem to turn silk scarves into doves don't really do it: It's just an illusion.
"I'm not sure I can see how matter is manipulated," I say. "I mean, well, maybe I can just about see how it can be..." And then my brain cartwheels around and I think I can see it all. "Hang on," I say. "Do we just see what the majority of people see? Like, I could think a tree and it wouldn't be there, but if lots of us thought a tree, that would be enough?"
"That's intriguing," says Burlem. "That's what we thought of last, before Lura started working on the book properly. But the world is not a projection of the Troposphere."
"Yes—that's very good," Lura says. "But I think it's got more to do with this idea of the machine code. Machine code is the code that makes the machine run, rather than the software. The machine code tells the software what to do. The machine code sets the rules for everything in the system: how the trees are invented in this computer-program world, for example."