The morning sun had fully risen now, casting long shadows down the narrow canyons that snaked between the buildings of old Florence. Shopkeepers had begun throwing open the metal grates that protected their shops and bars, and the air was heavy with the aromas of morning espresso and freshly baked cornetti.
Despite a gnawing hunger, Langdon kept moving. I've got to find the mask ... and see what's hidden on the back.
As Langdon led Sienna northward along the slender Via dei Leoni, he was having a hard time getting used to the sight of her bald head. Her radically altered appearance reminded him that he barely knew her. They were moving in the direction of Piazza del Duomo-the square where Ignazio Busoni had been found dead after placing his final phone call.
Robert, Ignazio had managed to say, breathless. What you seek is safely hidden. The gates are open to you, but you must hurry. Paradise Twenty-five. Godspeed.
Paradise Twenty-five, Langdon repeated to himself, still puzzled that Ignazio Busoni had recalled Dante's text well enough to reference a specific canto off the top of his head. Something about that canto was apparently memorable to Busoni. Whatever it was, Langdon knew he would find out soon enough, as soon as he laid his hands on a copy of the text, which he could easily do at any number of locations up ahead.
His shoulder-length wig was beginning to itch now, and though he felt somewhat ridiculous in his disguise, he had to admit that Sienna's impromptu styling had been an effective ruse. Nobody had given them a second look, not even the police reinforcements who had just rushed past them en route to the Palazzo Vecchio.
Sienna had been walking in total silence beside him for several minutes, and Langdon glanced over to make sure she was okay. She seemed miles away, probably trying to accept the fact that she had just killed the woman who had been chasing them.
"Lira for your thoughts," he ventured lightly, hoping to pull her mind from the image of the spike-haired woman lying dead on the palazzo floor.
Sienna emerged slowly from her contemplations. "I was thinking of Zobrist," she said slowly. "Trying to recall anything else I might know about him."
She shrugged. "Most of what I know is from a controversial essay he wrote a few years ago. It really stayed with me. Among the medical community, it instantly went viral." She winced. "Sorry, bad choice of words."
Langdon gave a grim chuckle. "Go on."
"His essay essentially declared that the human race was on the brink of extinction, and that unless we had a catastrophic event that precipitously decreased global population growth, our species would not survive another hundred years."
Langdon turned and stared at her. "A single century?"
"It was a pretty stark thesis. The predicted time frame was substantially shorter than previous estimates, but it was supported by some very potent scientific data. He made a lot of enemies by declaring that all doctors should stop practicing medicine because extending the human life span was only exacerbating the population problem."
Langdon now understood why the article spread wildly through the medical community.
"Not surprisingly," Sienna continued, "Zobrist was immediately attacked from all sides-politicians, clergy, the World Health Organization-all of whom derided him as a doomsayer lunatic who was simply trying to cause panic. They took particular umbrage at his statement that today's youth, if they chose to reproduce, would have offspring that literally would witness the end of the human race. Zobrist illustrated his point with a 'Doomsday Clock,' which showed that if the entire span of human life on earth were compressed into a single hour ... we are now in its final seconds."
"I've actually seen that clock online," Langdon said.
"Yes, well, it's his, and it caused quite an uproar. The biggest backlash against Zobrist, however, came when he declared that his advances in genetic engineering would be far more helpful to mankind if they were used not to cure disease, but rather to create it."
"Yes, he argued that his technology should be used to limit population growth by creating hybrid strains of disease that our modern medicine would be unable to cure."
Langdon felt a rising dread as his mind conjured images of strange, hybrid "designer viruses" that, once released, were totally unstoppable.
"Over a few short years," Sienna said, "Zobrist went from being the toast of the medical world to being a total outcast. An anathema." She paused, a look of compassion crossing her face. "It's really no wonder he snapped and killed himself. Even sadder because his thesis is probably correct."
Langdon almost fell over. "I'm sorry-you think he's right?!"
Sienna gave him a solemn shrug. "Robert, speaking from a purely scientific standpoint-all logic, no heart-I can tell you without a doubt that without some kind of drastic change, the end of our species is coming. And it's coming fast. It won't be fire, brimstone, apocalypse, or nuclear war ... it will be total collapse due to the number of people on the planet. The mathematics is indisputable."
"I've studied a fair amount of biology," she said, "and it's quite normal for a species to go extinct simply as a result of overpopulating its environment. Picture a colony of surface algae living in a tiny pond in the forest, enjoying the pond's perfect balance of nutrients. Unchecked, they reproduce so wildly that they quickly cover the pond's entire surface, blotting out the sun and thereby preventing the growth of the nutrients in the pond. Having sapped everything possible from their environment, the algae quickly die and disappear without a trace." She gave a heavy sigh. "A similar fate could easily await mankind. Far sooner and faster than any of us imagine."
Langdon felt deeply unsettled. "But ... that seems impossible."
"Not impossible, Robert, just unthinkable. The human mind has a primitive ego defense mechanism that negates all realities that produce too much stress for the brain to handle. It's called denial."
"I've heard of denial," Langdon quipped blithely, "but I don't think it exists."
Sienna rolled her eyes. "Cute, but believe me, it's very real. Denial is a critical part of the human coping mechanism. Without it, we would all wake up terrified every morning about all the ways we could die. Instead, our minds block out our existential fears by focusing on stresses we can handle-like getting to work on time or paying our taxes. If we have wider, existential fears, we jettison them very quickly, refocusing on simple tasks and daily trivialities."
Langdon recalled a recent Web-tracking study of students at some Ivy League universities which revealed that even highly intellectual users displayed an instinctual tendency toward denial. According to the study, the vast majority of university students, after clicking on a depressing news article about arctic ice melt or species extinction, would quickly exit that page in favor of something trivial that purged their minds of fear; favorite choices included sports highlights, funny cat videos, and celebrity gossip.
"In ancient mythology," Langdon offered, "a hero in denial is the ultimate manifestation of hubris and pride. No man is more prideful than he who believes himself immune to the dangers of the world. Dante clearly agreed, denouncing pride as the worst of the seven deadly sins ... and punished the prideful in the deepest ring of the inferno."
Sienna reflected a moment and then continued. "Zobrist's article accused many of the world's leaders of being in extreme denial ... putting their heads in the sand. He was particularly critical of the World Health Organization."
"I bet that went over well."
"They reacted by equating him with a religious zealot on a street corner holding a sign that says 'The End Is Near.' "
"Harvard Square has a couple of those."
"Yes, and we all ignore them because none of us can imagine it will happen. But believe me, just because the human mind can't imagine something happening ... doesn't mean it won't."
"You almost sound like you're a fan of Zobrist's."
"I'm a fan of the truth," she replied forcefully, "even if it's painfully hard to accept."
Langdon fell silent, again feeling strangely isolated from Sienna at the moment, trying to understand her bizarre combination of passion and detachment.
Sienna glanced over at him, her face softening
. "Robert, look, I'm not saying Zobrist is correct that a plague that kills half the world's people is the answer to overpopulation. Nor am I saying we should stop curing the sick. What I am saying is that our current path is a pretty simple formula for destruction. Population growth is an exponential progression occurring within a system of finite space and limited resources. The end will arrive very abruptly. Our experience will not be that of slowly running out of gas ... it will be more like driving off a cliff."
Langdon exhaled, trying to process everything he had just heard.
"Speaking of which," she added, somberly pointing up in the air to their right, "I'm pretty sure that's where Zobrist jumped."
Langdon glanced up and saw that they were just passing the austere stone facade of the Bargello Museum to their right. Behind it, the tapered spire of the Badia tower rose above the surrounding structures. He stared at the top of the tower, wondering why Zobrist had jumped and hoped to hell it wasn't because the man had done something terrible and hadn't wanted to face what was coming.
"Critics of Zobrist," Sienna said, "like to point out how paradoxical it is that many of the genetic technologies he developed are now extending life expectancy dramatically."
"Which only compounds the population problem."
"Exactly. Zobrist once said publicly that he wished he could put the genie back in the bottle and erase some of his contributions to human longevity. I suppose that makes sense ideologically. The longer we live, the more our resources go to supporting the elderly and ailing."
Langdon nodded. "I've read that in the U.S. some sixty percent of health care costs go to support patients during the last six months of their lives."
"True, and while our brains say, 'This is insane,' our hearts say, 'Keep Grandma alive as long as we can.' "
Langdon nodded. "It's the conflict between Apollo and Dionysus-a famous dilemma in mythology. It's the age-old battle between mind and heart, which seldom want the same thing."
The mythological reference, Langdon had heard, was now being used in AA meetings to describe the alcoholic who stares at a glass of alcohol, his brain knowing it will harm him, but his heart craving the comfort it will provide. The message apparently was: Don't feel alone-even the gods were conflicted.
"Who needs agathusia?" Sienna whispered suddenly.
Sienna glanced up. "I finally remembered the name of Zobrist's essay. It was called: 'Who Needs Agathusia?' "
Langdon had never heard the word agathusia, but took his best guess based on its Greek roots-agathos and thusia. "Agathusia ... would be a 'good sacrifice'?"
"Almost. Its actual meaning is 'a self-sacrifice for the common good.' " She paused. "Otherwise known as benevolent suicide."
Langdon had indeed heard this term before-once in relation to a bankrupt father who killed himself so his family could collect his life insurance, and a second time to describe a remorseful serial killer who ended his life fearing he couldn't control his impulse to kill.
The most chilling example Langdon recalled, however, was in the 1967 novel Logan's Run, which depicted a future society in which everyone gladly agreed to commit suicide at age twenty-one-thus fully enjoying their youth while not letting their numbers or old age stress the planet's limited resources. If Langdon recalled correctly, the movie version of Logan's Run had increased the "termination age" from twenty-one to thirty, no doubt in an attempt to make the film more palatable to the box office's crucial eighteen-to-twenty-five demographic.
"So, Zobrist's essay ..." Langdon said. "I'm not sure I understand the title. 'Who Needs Agathusia?' Was he saying it sarcastically? As in who needs benevolent suicide ... we all do?"
"Actually no, the title is a pun."
Langdon shook his head, not seeing it.
"Who needs suicide-as in the W-H-O-the World Health Organization. In his essay, Zobrist railed against the director of the WHO-Dr. Elizabeth Sinskey-who has been there forever and, according to Zobrist, is not taking population control seriously. His article was saying that the WHO would be better off if Director Sinskey killed herself."
"The perils of being a genius, I guess. Oftentimes, those special brains, the ones that are capable of focusing more intently than others, do so at the expense of emotional maturity."
Langdon pictured the articles he had seen about the young Sienna, the child prodigy with the 208 IQ and off-the-chart intellectual function. Langdon wondered if, in talking about Zobrist, she was also, on some level, talking about herself; he also wondered how long she would choose to keep her secret.
Up ahead, Langdon spotted the landmark he had been looking for. After crossing the Via dei Leoni, Langdon led her to the intersection of an exceptionally narrow street-more of an alleyway. The sign overhead read VIA DANTE ALIGHIERI.
"It sounds like you know a lot about the human brain," Langdon said. "Was that your area of concentration in medical school?"
"No, but when I was a kid, I read a lot. I became interested in brain science because I had some ... medical issues."
Langdon shot her a curious look, hoping she would continue.
"My brain ..." Sienna said quietly. "It grew differently from most kids', and it caused some ... problems. I spent a lot of time trying to figure out what was wrong with me, and in the process I learned a lot about neuroscience." She caught Langdon's eye. "And yes, my baldness is related to my medical condition."
Langdon averted his eyes, embarrassed he'd asked.
"Don't worry about it," she said. "I've learned to live with it."
As they moved into the cold air of the shadowed alleyway, Langdon considered everything he had just learned about Zobrist and his alarming philosophical positions.
A recurring question nagged at him. "These soldiers," Langdon began. "The ones trying to kill us. Who are they? It makes no sense. If Zobrist has put a potential plague out there, wouldn't everyone be on the same side, working to stop its release?"
"Not necessarily. Zobrist may be a pariah in the medical community, but he probably has a legion of devout fans of his ideology-people who agree that a culling is a necessary evil to save the planet. For all we know, these soldiers are trying to ensure that Zobrist's vision is realized."
Zobrist's own private army of disciples? Langdon considered the possibility. Admittedly, history was full of zealots and cults who killed themselves because of all kinds of crazy notions-a belief that their leader is the Messiah, a belief that a spaceship is waiting for them behind the moon, a belief that Judgment Day is imminent. The speculation about population control was at least grounded in science, and yet something about these soldiers still didn't feel right to Langdon.
"I just can't believe that a bunch of trained soldiers would knowingly agree to kill innocent masses ... all the while fearing they might get sick and die themselves."
Sienna shot him a puzzled look. "Robert, what do you think soldiers do when they go to war? They kill innocent people and risk their own death. Anything is possible when people believe in a cause."
"A cause? Releasing a plague?"
Sienna glanced at him, her brown eyes probing. "Robert, the cause is not releasing a plague ... it's saving the world." She paused. "One of the passages in Bertrand Zobrist's essay that got a lot of people talking was a very pointed hypothetical question. I want you to answer it."
"What's the question?"
"Zobrist asked the following: If you could throw a switch and randomly kill half the population on earth, would you do it?"
"Of course not."
"Okay. But what if you were told that if you didn't throw that switch right now, the human race would be extinct in the next hundred years?" She paused. "Would you throw it then? Even if it meant you might murder friends, family, and possibly even yourself?"
"Sienna, I can't possibly-"
"It's a hypothetical question," she said. "Would you kill half the population today in order to save our species from extinction?"
Langdon felt deeply disturbed by the macabre subject they were discussing, and so he was grateful to see a familiar red banner hanging on the side of a stone building just ahead.
"Look," he announced, pointing. "We're here."
Sienna shook her head. "Like I said. Denial."