Isaac’s diagram was now covered in little crosses where he located the various disciplines. He looked at Yagharek and drew a neat, final, careful x in the very centre of the triangle.

“Now what are we looking at right here? What’s bang in the middle?

“Some people think that’s mathematics there. Fine. But if maths is the study that best allows you to think your way to the centre, what’re the forces you’re investigating? Maths is totally abstract, at one level, square roots of minus one and the like; but the world is nothing if not rigorously mathematical. So this is a way of looking at the world which unifies all the forces: mental, social, physical.

“If the subjects are located in one triangle, with three nodes and one centre, then so are the forces and dynamics they study. In other words, if you think this way of looking at things is interesting or helpful, then there’s basically one kind of field, one kind of force, being studied in its various aspects here. That’s why this is called ‘Unified Field Theory.’ ”

Isaac smiled, exhausted. Godspit, he realized suddenly, I’m doing rather a good job of this…Ten years of research have improved my teaching…Yagharek was watching him carefully.

“I…understand…” the garuda finally said.

“I’m glad to hear it. There’s more, old son, so gird your loins. UFT’s not very accepted as a theory, you know. It’s probably about the status of the Fractured Land Hypothesis, if that means anything to you.” Yagharek nodded. “Fine, you know what I mean, then. Just about respectable, but a bit crackpot. However, to shred the last vestiges of credibility I might have been able to muster, I subscribe to a minority view among UFT theorists. That’s over the nature of the forces under investigation.

“I’ll try and keep this simple.” Isaac squeezed his eyes closed for a minute and gathered his thoughts. “Right. The question is whether it’s pathological for a dropped egg to fall.”

He paused and let the image hang for a minute.

“See, if you think that matter and therefore the unified force under investigation are essentially static, then falling, flying, rolling, changing your mind, casting a spell, growing older, moving, are basically deviations from an essential state. Otherwise, you think that motion is part of the fabric of ontology, and the question’s how best to theorize that. You can tell where my sympathies lie. Staticists would say I’m misrepresenting them, but fuck it.

“So I’m a MUFTI, a Moving Unified Field Theorist. Not a SUFTI, a Static Unified…you get the idea. But then, being a MUFTI raises as many problems as it solves: if it moves, how does it move? Steady gait? Punctuated inversion?

“When you pick up a piece of wood and hold it ten feet above the ground, it has more energy than when it’s on the ground. We call that potential energy, right? That’s not controversial among any scientist. Potential energy’s the energy that gives the wood the power to hurt you or mark the floor, a power it doesn’t have when it’s just resting on the ground. It has that energy when it’s motionless, like it was before, but when it could fall If it does, the potential energy turns into kinetic energy, and you break your toe or whatever.

“See, potential energy’s all about placing something in a situation where it’s teetering, where it’s about to change its state. Just like when you put enough strain on a group of people, they’ll suddenly explode. They’ll go from grumpy and quiescent to violent and creative in one moment. The transition from one state to another’s affected by taking something-a social group, a piece of wood, a hex-to a place where its interactions with other forces make its own energy pull against its current state.

“I’m talking about taking things to the point of crisis!”

Isaac sat back for a minute. To his surprise, he was loving this. The process of explaining his theoretical approach was consolidating his ideas, making him formulate his approach with a tentative rigour.

Yagharek was a model pupil. His attention was totally unwavering, his eyes as sharp as stilettos.

Isaac took a long breath and continued.

“This is major shit we’re dealing with here, Yag mate. I’ve been nibbling at crisis theory for arsing years. In a nutshell: I’m saying it’s in the nature of things to enter crisis, as part of what they are. Things turn themselves inside out by virtue of being things, understand? The force that pushes the unified field on is crisis energy. Stuff like potential energy, that’s one aspect of crisis energy, one tiny partial manifestation. Now, if you could tap the reserves of crisis energy in any given situation, you’re talking about enormous power. Some situations are more crisis-ridden or -prone than others, yes, but the point of crisis theory is that things are in crisis just as part of being. There’s loads of sodding crisis energy flowing around all the time, but we haven’t yet learnt how to tap it efficiently. Instead it bursts over unreliably and uncontrollably every so often. Terrible waste.”

Isaac shook his head at the thought.

“The vodyanoi can tap crisis energy, I think. In a tiny, tiny way. It’s paradoxical. You tap the existing crisis energy in the water to hold it in a shape it fights against, so you put it in more crisis…but then there’s nowhere for the energy to go, so the crisis resolves itself by breaking down into its original form. But what if the vodyanoi used water they’d already…uh…watercraefted, and used it as a constituent for some experiment that drew on the increased crisis energy…Sorry. I’m digressing. The point is, I’m trying to work out a way for you to tap into your crisis energy, and channel it to flight. See, if I’m right, it’s the only force that’s always going to be…suffusing you. And the more you fly, the more you’re in crisis, the more you should be able to fly…That’s the theory, anyway…

“But to be honest, Yag, this is much bigger than that. If I can really unlock crisis energy for you, then your case becomes, frankly, a pretty paltry concern. We’re talking about forces and energy that could totally change…everything…”

The incredible idea stilled the air. The dirty environs of the warehouse seemed too small and mean for this conversation.

Isaac stared out of the window into the grubby New Crobuzon night. The moon and her daughters were dancing sedately above him. The daughters, smaller than their mother but bigger than stars, shone hard and cold above him. Isaac thought about crisis.

Eventually Yagharek spoke.

“And if you are right…I will fly?”

Isaac burst into laughter at the bathetic demand.

“Yes, yes, Yag old son. If I’m right, you’ll fly again.”