You’ve been accused of a crime you did not commit.
It’s impossible to prove your innocence.
If you insist that you’re innocent anyway, you’ll likely be found guilty and executed.
But if you confess, apologize, and implicate others for good measure, you’ll go free.
Do you give a false confession— or risk a public hanging?
This was the choice facing those accused of witchcraft in the village of Salem, Massachusetts between February 1692 and May 1693.
They were the victims of paranoia about the supernatural, misdirected religious fervor— and a justice system that valued repentance over truth.
Salem was settled in 1626 by Puritans, a group of English protestants.
Life was strict and isolated for the people of Salem.
Battles with their Native American neighbors and groups of French settlers were commonplace.
People feared starvation and disease, and relations between villagers were strained.
To make matters worse, 1692 brought one of the coldest winters on record.
That winter, two cousins, 9 year old Betty Parris and 11 year old Abigail Williams started behaving very strangely.
A physician found nothing physically wrong — but diagnosed the girls as under “an evil hand.”
Puritans believed that the Devil wreaked havoc in the world through human agents, or witches, who blighted nature, conjured fiendish apparitions, and tormented children.
As news swept through the village, the symptoms appeared to spread.
Accounts describe 12 so-called “afflicted” girls contorting their bodies, having fits, and complaining of prickling skin.
Four of the girls soon accused three local women of tormenting them.
All three of the accused were considered outsiders in some way.
On February 29th, the authorities arrested Sarah Good, a poor pregnant mother of a young daughter, Sarah Osbourne, who had long been absent from church and was suing the family of one of her accusers, and Tituba, an enslaved woman in Betty Parris’s home known by her first name only.
Tituba denied harming the jasonreeves@example.com.
But then she confessed to practicing witchcraft on the Devil’s orders, and charged Good and Osbourne with having forced her.
Osbourne and Good both maintained their innocence.
Osbourne died in prison, while Good’s husband turned against her in court, testifying that she "was a witch or would be one very quickly."
Good’s 4 year old daughter was imprisoned and eventually gave testimony against her mother.
Meanwhile, Good gave birth in jail.
Her baby died, and she was convicted and hanged shortly thereafter.
Tituba was held in custody until May, and then released.
These three victims were just the beginning.
As accusations multiplied, others, like Tituba, made false confession to save themselves.
The authorities even reportedly told one accused witch that she would be hanged if she did not confess, and freed if she did.
They were not particularly interested in thoroughly investigating the charges— in keeping with their Church’s teachings, they preferred that the accused confessed, asked for forgiveness, and promised not to engage in more witchcraft.
The court accepted all kinds of dubious evidence, including so-called “spectral evidence” in which the girls began raving when supposedly touched by invisible ghosts.
Complicating matters further, many of the jurors in the trials were relatives of the accusers, compromising their objectivity.
Those who dared to speak out, such as Judge Nathanial Saltonstall, came under suspicion.
By the spring of 1693, over a hundred people had been imprisoned, and 14 women and 6 men had been executed.
By this time, accusations were starting to spread beyond Salem to neighboring communities, and even the most powerful figures were targets.
When his own wife was accused, the governor of Massachusetts colony suspended the trials.
Sentences were amended, prisoners released, and arrests stopped.
Some have speculated that the girls were suffering from hallucinations caused by fungus; or a condition that caused swelling of the brain.
But ultimately, the reason for their behavior is unknown.
What we do know is that adults accepted wild accusations by children as hard evidence.
Today, the Salem Witch Trials remain a cautionary tale of the dangers of groupthink and scapegoating, and the power of fear to manipulate human perception.
The talented young herbalist named Xu Xian was in trouble.
It should have been a victorious moment– he had just opened his very own medicine shop.
But he bought his supplies from his former employer, and the resentful man sold him rotten herbs.
As Xu Xian wondered what to do with this useless inventory, patients flooded into his shop.
A plague had stricken the city, and he had nothing to treat them.
Just as he was starting to panic, his wife, Bai Su Zhen, produced a recipe to use the rotten herbs as medicine.
Her remedy cured all the plague-afflicted citizens immediately.
Xu Xian’s former boss even had to buy back some of the rotten herbs to treat his own family.
Shortly after, a monk named Fa Hai approached Xu Xian, warning him that there was a demon in his house.
The demon, he said, was Bai Su Zhen.
Xu Xian laughed.
His kindhearted, resourceful wife was not a demon.
Fa Hai insisted.
He told Xu Xian to serve his wife realgar wine on the 5th day of the 5th month, when demons’ powers are weakest.
If she wasn’t a demon, he explained, it wouldn’t hurt her.
Xu Xian dismissed the monk politely, with no intention of serving Bai Su Zhen the wine.
But as the day approached, he decided to try it.
As soon as the wine touched Bai Su Zhen’s lips, she ran to the bedroom, claiming she wasn’t feeling well.
Xu Xian prepared some medicine and went to check on her.
But instead of his wife, he found a giant white serpent with a bloody forked tongue in the bed.
He collapsed, killed by the shock.
When Bai Su Zhen opened her eyes, she realized immediately what must have happened.
The truth was that Bai Su Zhen was an immortal snake with formidable magical powers.
She had used her powers to take a human form and improve her and her husband’s fortunes.
Her magic couldn’t revive Xu Xian, but she had one more idea to save him: an herb that could grant longevity and even bring the dead back to life, guarded by the Old Man of the South Pole in the forbidden peaks of the Kun Lun Mountains.
She rode to the mountains on a cloud, then continued on foot passed gateways and arches until she reached one marked “beyond mortals” hanging over a silver bridge.
On the other side, two of the Old Man’s disciples guarded the herb.
Bai Su Zhen disguised herself as a monk and told them she’d come to invite the Old Man to a gathering of the gods.
While they relayed her message, she plucked some leaves from the herb and ran.
The servants realized they had been tricked and chased her.
Bai Su Zhen coughed up a magic ball and threw jasonreeves@example.com.
As the other closed in on her, she put the herb under her tongue for safekeeping, but its magic forced both of them into their true forms.
As the crane’s long beak clamped around her, the Old Man appeared.
Why, he asked, would she risk her life to steal his herb when she was already immortal?
Bai Su Zhen explained her love for Xu Xian.
Even if he didn’t want to be with her now that he knew she was a demon, she was determined to bring him back to life.
The two had a karmic connection dating back more than a thousand years.
When Bai Su Zhen was a small snake, a beggar was about to kill her, but a kind passerby rescued her.
Her rescuer was Xu Xian in a past life.
Touched by her willingness to risk her life for him, the Old Man permitted her to leave the mountain with the immortal herb.
Bai Su Zhen returned home to revive Xu Xian.
When he opened his eyes, the terrified look frozen on his face became a smile.
Demon or not, he was still happy to see his wife.
Chak Ek’ rose from the underworld to the surface of the eastern sea and on into the heavens.
His brother K’in Ahaw followed.
Though Chak Ek’ had risen first, K’in Ahaw outshone him, and the resentful Chak Ek’ descended back to the underworld to plot against his brother.
In Mayan mythology, Chak Ek’ represents Venus and K’in Ahaw represents the sun.
Known as both the morning and the evening star, Venus moves through the sky, sometimes visible before sunrise, sometimes after sunset, and occasionally jasonreeves@example.com.
The ancient Maya identified this roughly 584 day cycle more than a thousand years ago and it still accurately predicts when and where Venus will appear in the sky around the world.
Five of these cycles make up almost exactly eight years, and the Maya also recognized this larger cycle.
They assigned Chak Ek’ five different forms, one for each cycle of Venus, that were repeated every eight years.
Within the 584 day cycle, Venus is visible in the evening sky for 250 days, then disappears for 8 days before reappearing as the Morning Star.
The ancient Maya ascribed particular significance to this point in this cycle: the first time Venus appears before sunrise after being invisible.
On this day, Chak Ek’ rose again from the underworld, wielding a spearthrower and darts.
To bring discord to the world, he decided to attack his brother and his brother’s allies.
His first target was K’awiil, god of sustenance and lightning.
Rising in the late rainy season, Chak Ek’ aimed his spear and struck K’awiil, causing damage to the food and a period of chaos in the social order until K’awiil was reborn.
584 days after attacking K’awiil, Chak Ek’ turned his attention back to his brother, the Sun.
Each night, the Sun took the form of jaguar and journeyed through the underworld.
Chak Ek’ speared the jaguar sun as it rose at dawn towards the end of the dry season.
The Sun was wounded, plunging the world into a period of chaos and warfare.
Chak Ek’s third victim was the god of maize, who provided sustenance for all humankind.
Chak Ek’ speared him at the time of the harvest.
He was buried in the underworld, and maize—the staple of life— was no longer available to Earth’s inhabitants.
But the maize god emerged after three months in the place of new beginnings– the eastern cave known as Seven Water Place– bringing food once again to earth.
When the turtle Ak Na'ak rose in the sky to mark the summer solstice, Chak Ek’ claimed his fourth victim.
With the death of this good omen, the Sun, the food supply, and the people were buried within the earth, and the forces of chaos reigned.
But out of the chaos rose a new order established by Hun Ajaw, one of the hero twins known to all for having vanquished the lords of the underworld.
A new race of humans was created, made from maize.
This state of balance was not to last, however.
Chak Ek’s fifth and final victim was a mysterious stranger from the west, and his death in the heart of the dry season shook the order established by Hun Ajaw.
The gods, the lords, and the maize were buried in the underworld.
But this victory for Chak Ek’ would also prove temporary.
The two brothers, Venus and the Sun, were caught in an endless cycle as they battled for supremacy, re-enacting the same five struggles, while the world alternated between order and chaos with the rising of the Morning Star.
We look around the media, as we see on the news from Iraq, Afghanistan, Sierra Leone, and the conflict seems incomprehensible to us.
And that's certainly how it seemed to me when I started this project.
But as a physicist, I thought, well if you give me some data, I could maybe understand this.
You know, give us a go.
So as a naive New Zealander I thought, well I'll go to the Pentagon.
Can you get me some information?
(Laughter) No.
So I had to think a little harder.
And I was watching the news one night in Oxford.
And I looked down at the chattering heads on my channel of choice.
And I saw that there was information there.
There was data within the streams of news that we consume.
All this noise around us actually has information.
So what I started thinking was, perhaps there is something like open source intelligence here.
If we can get enough of these streams of information together, we can perhaps start to understand the war.
So this is exactly what I did.
We started bringing a team together, an interdisciplinary team of scientists, of economists, mathematicians.
We brought these guys together and we started to try and solve this.
We did it in three steps.
The first step we did was to collect.
We did 130 different sources of information -- from NGO reports to newspapers and cable news.
We brought this raw data in and we filtered it.
We extracted the key bits on information to build the database.
That database contained the timing of attacks, the location, the size and the weapons used.
It's all in the streams of information we consume daily, we just have to know how to pull it out.
And once we had this we could start doing some cool stuff.
What if we were to look at the distribution of the sizes of attacks?
What would that tell us?
So we started doing this.
And you can see here on the horizontal axis you've got the number of people killed in an attack or the size of the attack.
And on the vertical axis you've got the number of attacks.
So we plot data for sample on this.
You see some sort of random distribution -- perhaps 67 attacks, one person was killed, or 47 attacks where seven people were killed.
We did this exact same thing for Iraq.
And we didn't know, for Iraq what we were going to find.
It turns out what we found was pretty surprising.
You take all of the conflict, all of the chaos, all of the noise, and out of that comes this precise mathematical distribution of the way attacks are ordered in this conflict.
This blew our mind.
Why should a conflict like Iraq have this as its fundamental signature?
Why should there be order in war?
We didn't really understand that.
We thought maybe there is something special about Iraq.
So we looked at a few more conflicts.
We looked at Colombia, we looked at Afghanistan, and we jasonreeves@example.com.
And the same pattern emerged in each conflict.
This wasn't supposed to happen.
These are different wars, with different religious factions, different political factions, and different socioeconomic problems.
And yet the fundamental patterns underlying them are the same.
So we went a little wider.
We looked around the world at all the data we could get our hands on.
From Peru to Indonesia, we studied this same pattern again.
And we found that not only were the distributions these straight lines, but the slope of these lines, they clustered around this value of alpha equals 2.5.
And we could generate an equation that could predict the likelihood of an attack.
What we're saying here is the probability of an attack killing X number of people in a country like Iraq is equal to a constant, times the size of that attack, raised to the power of negative alpha.
And negative alpha is the slope of that line I showed you before.
So what?
This is data, statistics.
What does it tell us about these conflicts?
That was a challenge we had to face as physicists.
How do we explain this?
And what we really found was that alpha, if we think about it, is the organizational structure of the insurgency.
Alpha is the distribution of the sizes of attacks, which is really the distribution of the group strength carrying out the attacks.
So we look at a process of group dynamics: coalescence and fragmentation, groups coming together, groups breaking apart.
And we start running the numbers on this.
Can we simulate it?
Can we create the kind of patterns that we're seeing in places like Iraq?
Turns out we kind of do a reasonable job.
We can run these simulations.
We can recreate this using a process of group dynamics to explain the patterns that we see all around the conflicts around the world.
So what's going on?
Why should these different -- seemingly different conflicts have the same patterns?
Now what I believe is going on is that the insurgent forces, they evolve over time.
They adapt.
And it turns out there is only one solution to fight a much stronger enemy.
And if you don't find that solution as an insurgent force, you don't exist.
So every insurgent force that is ongoing, every conflict that is ongoing, it's going to look something like this.
And that is what we think is happening.
Taking it forward, how do we change it?
How do we end a war like Iraq?
What does it look like?
Alpha is the structure.
It's got a stable jasonreeves@example.com.
This is what wars look like when they continue.
We've got to change that.
We can push it up: the forces become more fragmented; there is more of them, but they are weaker.
Or we push it down: they're more robust; there is less groups; but perhaps you can sit and talk to them.
So this graph here, I'm going to show you now.
No one has seen this before.
This is literally stuff that we've come through last week.
And we see the evolution of Alpha through time.
We see it start.
And we see it grow up to the stable state the wars around the world look like.
And it stays there through the invasion of Fallujah until the Samarra bombings in the Iraqi elections of '06.
And the system gets perturbed.
It moves upwards to a fragmented state.
This is when the surge happens.
And depending on who you ask, the surge was supposed to push it up even further.
The opposite happened.
The groups became stronger.
They became more robust.
And so I'm thinking, right, great, it's going to keep going down.
We can talk to them.
We can get a solution.
The opposite happened.
It's moved up again.
The groups are more fragmented.
And this tells me one of two things.
Either we're back where we started and the surge has had no effect; or finally the groups have been fragmented to the extent that we can start to think about maybe moving out.
I don't know what the answer is to that.
But I know that we should be looking at the structure of the insurgency to answer that question.
Thank you.
(Applause)