The room shivered around Marcelina, spraying off multiple realities like a dog shaking water from its coat.

“So it’s some kind of hallucinogen, like ayahuasca.”

“No, nothing like ayahuasca. The iâos of the bença believe that the Daime stimulates those parts of the brain that generate the sensations of spirituality. Cutupairá shows the literal truth. The eye of the frog is so sensitive that it can perceive a single photon of light, a single quantum event. The frog sees the fundamental quantum nature of reality.”

The snap was on Marcelina’s lip: And what does a capoeira Mestre know about quantum theory? In surliness was security; she was in a place as familiar and comfortable as home, yet the step from the yard where she played the great game into the green, blue, and yellow kitchen was the step from one world to another. Rio had always been a city of shifting realities, hill and sea, the apartment buildings that grew out of the sheer rock of the morros, the jarring abutments of million-real houses with favela newlywed blocks, piled one on top of another. And where the realities overlap, violence spills through. Heitor, whose private life you entered through books, had so many times tried to explain quantum theory to Marcelina, usually when she just wanted him to tell her how hot her ass looked in the latest little mesh number. All she understood of it was that her career depended on it and that there were three interpretations (as she tried to get him to take a line from the glass-top table), only one of which could be true; but whichever one was, it meant that reality was completely different from what common sense told us. So shut up the mouth and listen to Mestre Yoda.

“Whatever’s in the frog skin allows our minds to perceive on the quantum level.”

“What did you see?”

“Like everything had a halo, had other selves … ” She hesitated over the two words that would turn her world upside down, shatter it into glittering dust. “Many worlds.”

There are three main interpretations of quantum theory , Heitor had said. It had been three days after carnaval, when all the marvelous city still had huge stashes of recreational drugs to use up before the feathers and the sequins and the skin glitter were put away and the world of work reaffirmed its dull authority. Marcelina had been reeling around the apartment blessed on 1guaçu white, practicing her booty shake before it was put away until the New Year Yemanja festival. The Copenhagen interpretation is considered a purely probabilistic interpretaation in that in physical terms it gives undue prominence to observation, information, and mind. The Bohm carrier-wave theory is essentially nonlocal, in that every particle in the universe is connected across space and time to every other, which has been seized on by various New Age charlatans as supporting mysticism. The Everett many-world theorem reconciles the paradoxes in quantum theory by positing a huge, maybe even infinite, number of parallel universes that contain every possible quantum state.

Why are you telling me this why is this important what does it mean come and have some coke , Marcelina had jabbered. She had never forgotten Heitor’s answer.

What it means is, any way you cut it, it’s a mad world.

Again the room, the fundação, Jesus on his mountain spasmed around Marcelina. I am seeing across multiple universes, parallel Rios, other Marcelinas. What of the ones I can’t see, the ones who were that hair too slow on Rua Rabata Ribeiro and were cut open under that knife? She took a sip of her strong, now-cold coffee.

“I think you’re going to have to explain this to me.”

Mestre Ginga sat back in his chair.

“Very well then. You won’t believe it, but every word is true.”

“There is not one world. There are many worlds. There is not one you; there are many yous. There is no universe; there is the multiverse, and all possible quantum states are contained within it. Write down ninety-nine point nine and as many nines after that until you get bored with it. That many universes are empty, sterile, exercises in abstract geometry and topology; two-dimen-sional, gravityless, impossible. Out of that chain-of-zeroes point one that remain, the greater part are universes where the constants of physics vary by a tiny degree, a decimal here or there, but even that minuscule variation means that the universe immediately collapses after the big bang into a black hole that expands infinitely in a fraction of a second so that every particle ends up so far from its neighbor that it is effectively in a universe of its own, where stars do not form, or burn out in a three-score and ten. And in the same fraction of those universes as they are to the multiverse, the fine-tuning of constants allows the ultimate unlikelihood of life to exist, to exist intelligently, to found empires and build beautiful Rios, to learn martial arts and make television programs and quest into the nature of the universe in which it finds itself so improbably. We have penetrated to ten to the three hundred thousand universes and still we are not a thumbnail’s thickness into the rind of the multiverse, let alone begun to exhaust the universes where we exist in some form recognizable to ourselves.

“Everyone’s got a theory. Ask any Rio taxi driver and he’ll give you his free. Taxi drivers know how to make a better country and a perfect Seleçao as well as all the best places to eat. What matters is, how useful is your theory? Does it explain the everyday as well as the weird and spooky? Physics is no different. We’ve had Newton and we’ve had Einstein and we’ve had Bohr and Heisenberg, and each time the theory gets a little better at explaining what’s real; but we’re still a long long way from a final Theory of Everything, the ultimate taxi driver theory that you plug a value in and it gives you everything from the reason there is something rather than nothing to the soccer results. Physics is now a roda: all the malandros standing round clapping and singing while two theories go in and try to out-jeito each other. There are two big strong boys who think they have the malandragem to be the theory of everything. One of them is String theory, or M-theory as it’s also called. Facing it in the ring is Loop Quantum Gravity. They’re calling names at each other, taking each other’s measure, trying to trick the other into a simple mistake they can use to make him look stupid, like you made Jair look stupid with that boca de calça. The LQG boys, they’re shouting at the String theorists that it’s not even wrong. The Stringeiros, they shout back that it’s just dreadlocks in space. Which is right? I’m just a guy who runs a capoeira school and who needs some theory to explain what a little book with a frog on the cover has shown him, and that’s a hell of a lot of parallel universes.

“Me, I go for dreadlocks in space. Loop Quantum Gravity’s main theory is that everything is made from space and time woven into itself. Everything can be made from loops of space and time pulled through themselves. Yeah, it’s not dreadlocks, it’s knitting. But I was reading on online forums — I read the physics forums, why shouldn’t I? — and there’s a guy in the terreiro at Rio U who says that maybe what we think of as space is just connections between pieces of information. Everything is connected information in time, and we have a word for that: it’s computer. The universe is one huge quantum computer; all matter, all energy, everything we are, are programs running on this computer. Now, stick with me here. What I know about quantum computers, they can exist in two contradictory states at the same time, and this allows them to do things no other computer could. But I know, because I’ve seen them, that reality is a multiverse, so those computations are being done in many universes at once, so in fact all the multiverse is one vast quantum computer. Everything is information. Everything is … thought. Out minds are part of it. Out minds run across many universes — maybe all of them. That’s what the curupairá does, reduces our perceptions to the level where we become aware that we are part of the multiverse quantum computer. And listen, listen well, if it’s all information, if it’s all thought and computation, then that information can be rewritten and edited. You can write yourself into any part of the multiverse, any place, any time. And another you has written herself into this universe, and will run you down and kill you. Think of her as a kind of policeman. A militar. She is part of an organization that polices the multiverse, that seeks to keep the true nature of reality secret, controlled only by a small, elite group. She will take your place, and then she hoped to use that to infiltrate us, and eliminate us all.