Speaker 1: Happy Saturday, everybody. Today we have one of our most
Speaker 1: unintentionally terrifying episodes of all time. It is on encephalitis lethargica,
Speaker 1: and it originally came out We did not ever intend
Speaker 1: for this to be a Halloween episode, but it originally
Speaker 1: came out in October and we heard from a lot
Speaker 1: of listeners that it scared them more than anything else
Speaker 1: we have ever done. So this story of a frightening
Speaker 1: and mysterious illness is also a good segue into a
Speaker 1: new show on our network. It's The End of the
Speaker 1: World with Josh Clark, and Josh, one of the hosts
Speaker 1: of the other podcast Stuff You Should Know, is hosting
Speaker 1: a ten part series that explores all of the various
Speaker 1: ways that humanity could abruptly end. So stay tuned at
Speaker 1: the end of today's episode for the trailer to the
Speaker 1: End of the World with Josh Clark. Enjoy. Welcome to
Speaker 1: Stuff You Missed in History Class from how Stuff Works
Speaker 1: dot Com. Hello, and welcome to the podcast. I'm Tracy B.
Speaker 1: Wilson and I'm probably so. I did not intend for
Speaker 1: today to be a Halloween episode. Is scary? Yeah, due
Speaker 1: to some quirks in our publishing schedule. It happens to
Speaker 1: be coming out right before Halloween. It is a listener
Speaker 1: request from listener Ellen or perhaps Ellen, And in researching it,
Speaker 1: I realized it was the most frightening thing I had
Speaker 1: ever learned about. So, so buckle up. History has scared Tracy.
Speaker 1: History has scared me. So. From nineteen sixteen to about
Speaker 1: nine seven, this really bizarre epidemic spread around the world.
Speaker 1: It came to be known as sleepy sickness, and it
Speaker 1: is not to be confused with sleeping sickness, which is
Speaker 1: a tropical disease found in sub Saharan Africa. This is
Speaker 1: another name for a disease called encephalitis lethargica, and it
Speaker 1: caused this really weird variety of symptoms, from drastic behavior
Speaker 1: changes to unusual eye movements. Especially in the beginning years
Speaker 1: of it. Uh, the really common element was this deep,
Speaker 1: prolonged sleep that went on and on from days two months,
Speaker 1: and people just couldn't wake up. Between twenty and of
Speaker 1: the people who got this disease died, and of the
Speaker 1: ones who survived, only about a third really fully recovered.
Speaker 1: The rest developed what came to be known as post
Speaker 1: and syphilitic Parkinson ism, and some of these patients persisted
Speaker 1: in a semi comatose state for decades. It's extra terrifying.
Speaker 1: The next part is even more terrifying. Yeah, as if
Speaker 1: all of this were not enough to scare the pants
Speaker 1: off of you. While in this extremely deep sleep that
Speaker 1: was part of many of the cases, people appeared to
Speaker 1: be unconscious, but in reality they were actually alert. They
Speaker 1: were completely aware of what was going on, but they
Speaker 1: were unable to overspeaks, so it was a sort of paralysis. Really. Yeah,
Speaker 1: So people today may have heard about this whole disease
Speaker 1: from the movie Awakenings starring Robin Williams, or maybe from
Speaker 1: the first pages of Neil Gaiman's amazing comic book series Sandman,
Speaker 1: which starts off when a ritual that was meant to
Speaker 1: capture death instead captures dream and causes people to sleep endlessly. Otherwise,
Speaker 1: it's pretty far in the background of medical history most
Speaker 1: of the time. It's not something that people remember all
Speaker 1: that well today. But from its onset until about ten
Speaker 1: years after it faded away, there were more than nine
Speaker 1: thousand papers and books published on it, so at the
Speaker 1: time it was a big deal. Even though people don't
Speaker 1: necessarily come up with it immediately when thinking about huge
Speaker 1: epidemics today. Yeah, and I wonder why that is, um
Speaker 1: talk about some of that. Yeah, Prolonged sleep as an
Speaker 1: illness has been reported really really way back into history.
Speaker 1: There are written records as early as Hippocrates of this
Speaker 1: kind of incident happening. And then there are also, of course,
Speaker 1: in our cultural consciousness tales like sleeping beauty and these
Speaker 1: stories like rip van Winkle uh, and some people along
Speaker 1: the line have theorized that these were actually rooted to
Speaker 1: some degree in some kind of sleeping illness. In the
Speaker 1: real world, there had also been an outbreak of a
Speaker 1: similar condition in Italy in eighteen eighty nine and eighteen ninety,
Speaker 1: which came to be known as Landona, and it was
Speaker 1: thought at the time to be a complication of the flu.
Speaker 1: And around the world, other outbreaks of encephalitis had also
Speaker 1: followed behind other epidemics, particularly the flu. This particular one
Speaker 1: started just a couple of years before the nineteen eighteen
Speaker 1: Spanish flu epidemic, which killed between twenty and forty million people,
Speaker 1: and when it came to the encephalitis lethargica epidemic, the
Speaker 1: first reports came at about the same time in two
Speaker 1: different places, which were France in Austria. In nineteen six,
Speaker 1: in France, a doctor named Genre nee Cruche started to
Speaker 1: see six soldiers with this weird assortment of seemingly unrelated
Speaker 1: neurological symptoms, and the one common element was that the
Speaker 1: patients just slept, apparently peacefully and deeply, and that they
Speaker 1: could not be woken up, and he started to wonder
Speaker 1: whether there was some kind of new chemical weapon at work.
Speaker 1: At about the same time, a British doctor named A. J.
Speaker 1: Hall also reported similar symptoms, and other troops who were
Speaker 1: stationed in France. In Vienna, it came to the attention
Speaker 1: of Romanian Austrian psychiatrists Constantine von Economo after a sleepy,
Speaker 1: disoriented civilian wandered into the Wagner Jarre clinic where he worked.
Speaker 1: The doctors there had mostly been treating soldiers who were
Speaker 1: wounded in the war, so they really weren't prepared for
Speaker 1: this apparently uninjured civilian with nothing physically wrong that they
Speaker 1: could really point to. And then more and more patients
Speaker 1: with similar symptoms arrived at the clinic and there you know,
Speaker 1: they had the similar part of this uncontrollable sleepiness and sleep.
Speaker 1: But the rest of their symptoms were so strange and
Speaker 1: diverse that the doctors were really at a loss to
Speaker 1: figure out a cause or a treatment. These patients had fevers, malaise,
Speaker 1: double vision, they became lethargic. Sometimes they had sore throats.
Speaker 1: Their eye muscles would start working and their eyes would
Speaker 1: dart around or roll back in their heads. Some of
Speaker 1: them developed very strange eye and tongue movement movements, and
Speaker 1: this variety of other neurological and psychiatric symptoms. A few
Speaker 1: of them even had uncontrollable hiccups, and one died of that.
Speaker 1: How does that work? Well, if you can't stop hiccuping,
Speaker 1: you can't really eat or sleep, and then it can
Speaker 1: cause all kinds of other interesting Yeah. Once again, throughout
Speaker 1: all of this, the common element was this strange deep
Speaker 1: sleep from which they could not be woken. Vanni Conomos
Speaker 1: saw this common element and said, we're dealing with a
Speaker 1: sleeping sickness. Yeah. He was really the one that just
Speaker 1: laid that out there, and he's a character on his own.
Speaker 1: He was also a pilot who had been serving in
Speaker 1: the war, but he came back home to Vienna after
Speaker 1: his brother was killed and he really wanted to be flying,
Speaker 1: but reluctantly transferred to doing medical work instead to try
Speaker 1: to keep himself more out of danger and spare his
Speaker 1: family from further grief. On top of all that, he
Speaker 1: was also a baron, having been born to a family
Speaker 1: of Greek aristocrats and then married the daughter of an
Speaker 1: Austrian prince. As the patient started to die from sleep,
Speaker 1: Vonni Konomos started an intense research effort to find a
Speaker 1: cause and a cure. He studied autopsies of patients who
Speaker 1: had died of the disease, and he found common areas
Speaker 1: of damage to their brains, specifically in the hypothalamus, and
Speaker 1: he suspected that the differences and how much people slept
Speaker 1: was related to just how their hypothalamus was damaged. He
Speaker 1: also found that brain tissue could transmit the disease to monkeys,
Speaker 1: so he concluded that they were looking at something that
Speaker 1: was contagious. He publicly announced his conclusion that they were
Speaker 1: dealing with a new disease, probably a virus, before the
Speaker 1: Psychiatric Society in Vienna, on April seventeenth of nineteen seventeen.
Speaker 1: Uh Consequently, sometimes the disease has been referred to as
Speaker 1: von Economo's disease. His announcement was not at all well received.
Speaker 1: At the time. The prevailing view was that mental illnesses
Speaker 1: were all products of things like trauma and buried memories.
Speaker 1: Freud was really at the forefront of psychology at this point,
Speaker 1: so a lot of people just scoffed at the idea
Speaker 1: that there could be a virus or other disease process
Speaker 1: causing the kinds of behavior changes and psychological problems that
Speaker 1: some of the patients were exhibiting. The ongoing debate and
Speaker 1: this mystery of the whole thing kept much progress from
Speaker 1: being made in terms of treatment and prevention. But then, uh,
Speaker 1: the illness mostly disappeared from continental Europe. It really just
Speaker 1: fell off suddenly, and Spanish flew on the rise, took
Speaker 1: its place, and it became a much more pressing priority.
Speaker 1: Not long after that, though, the disease appeared in London
Speaker 1: and it followed much the same pattern as it had
Speaker 1: on the continent. There were, you know, all these patients
Speaker 1: who were suddenly having the strange collective collection of symptoms
Speaker 1: and sleeping constantly. The government in Britain quickly made it
Speaker 1: a reportable disease. The Ministry of Health had to be
Speaker 1: notified of all new cases and its appearance and spread
Speaker 1: UH in London was much like it had been in
Speaker 1: France and Austria. Strange symptoms and unending sleep uh you know,
Speaker 1: baffling the doctors. But in England the symptoms became even
Speaker 1: more alarming, with patients who could never sleep, or who
Speaker 1: couldn't stop laughing, or had other strange physical or emotional
Speaker 1: present sians It also seemed like fewer and fewer people
Speaker 1: were truly recovering. In Austria and France, there had been
Speaker 1: people that had gotten better, but as it's spread around England,
Speaker 1: a lot of people were becoming comatose or developing. As
Speaker 1: we mentioned at the beginning, what later it came to
Speaker 1: be known as post and syphilitic parkinson is um or PEP.
Speaker 1: Sometimes the onset of parkinson Is m happened years after
Speaker 1: people recovered, after they had apparently been healthy all that time.
Speaker 1: During the epidemic, the average age for the onset of
Speaker 1: Parkinson's dropped to thirty six years old. Today, while there
Speaker 1: are people who have early onset, the average age for
Speaker 1: people to start exhibiting Parkinson's is sixty. So this was
Speaker 1: really a significant and strange happening. Uh. Following the epidemic,
Speaker 1: two thirds of Parkinson's patients had previously had encephalitis, so
Speaker 1: it clearly was causing it. Right, this, this disease is
Speaker 1: was causing a drastic shift in who developed Parkinson's and when.
Speaker 1: And we're going to pause before we start talking about
Speaker 1: how then the rest of the world gets to be terrified.
Speaker 1: So to return to the story of encephalitis lethargica from England,
Speaker 1: the disease spread all over the globe, and the same
Speaker 1: story just played out over and over and over. People
Speaker 1: would start showing up with these strange symptoms that prevent
Speaker 1: that presented themselves in such different ways that it would
Speaker 1: take a while for doctors to realize what was happening.
Speaker 1: It really didn't help that the epidemic had started just
Speaker 1: at the end of World War One and just before
Speaker 1: the start of the nineteen eighteen Spanish flu epidemic, and
Speaker 1: so resources were just scarce and there were definitely bigger
Speaker 1: priorities going on. And this crazy, although terrifying disease, and
Speaker 1: as it spread, it started to prompt a variety of
Speaker 1: different sleep disorders. So while some patients would sleep for
Speaker 1: months at a time, others couldn't sleep at all, and
Speaker 1: they would actually die of exhaustion. The disease came to
Speaker 1: be known in some places as epidemic encephalitis rather than
Speaker 1: encephalitis lethargica, since not everyone could really be called lethargic anymore.
Speaker 1: As its spread, it also started to affect more and
Speaker 1: more children and young people. Children who contracted the disease
Speaker 1: developed impulse control issues that led to them having violent
Speaker 1: behavior in their adolescence. Some of them injured themselves or
Speaker 1: other people. One even removed her own eyes and several
Speaker 1: of her own teeth okay after unclenched. After that um,
Speaker 1: this behavior often would continue for the rest of these
Speaker 1: patients lives after they progress out of childhood, unless post
Speaker 1: and cephalitic parkinson is M made them physically unable to continue.
Speaker 1: For children with the disease, outbursts were so severe that
Speaker 1: many had to be institutionalized. Hospitals and asylums that were
Speaker 1: accustomed to providing care for adults suddenly had to develop
Speaker 1: new practices to care for children because there were so
Speaker 1: many suddenly having to move into institutions. Researchers theorized that
Speaker 1: the reason this encephalitis was causing behavior changes like this
Speaker 1: and young people was because their brains hadn't yet developed
Speaker 1: the capacity for self control that adults typically had by
Speaker 1: the time they were infected, and this tendency towards violent
Speaker 1: behavior and other erratic behavior even led to encephalitis lethargica
Speaker 1: being blamed for gangster behavior and lawlessness during the nineteen twenties.
Speaker 1: Once this disease spread to the United States, neurologist Frederick Tilney,
Speaker 1: who was known as Fred and had also been Helen
Speaker 1: Keller's neurologist, became the country's foremost authority on sleepy sickness.
Speaker 1: One of his most famous encephalitis patients was Jesse Morgan,
Speaker 1: who was the wife of Jack p Morgan, who himself
Speaker 1: was the son of banker and full anthropist John Pierpoint Morgan.
Speaker 1: She got the disease in After Jesse's death, Jack donated
Speaker 1: two hundred thousand dollars to the Neurological Institute to fund
Speaker 1: research into this disease. The Neurological Institute was behind most
Speaker 1: of the research into encephalitis lethargica that came from that point.
Speaker 1: Later on, William Matheson, who was the wealthy founder of
Speaker 1: a chemical company and an encephalitis patient started the Matheson
Speaker 1: Commission to fund research at the Neurological Institute, with Dr
Speaker 1: Josephine B. Neil, who was an encephalitis expert, helming the
Speaker 1: project and the commission's aim was to study the disease
Speaker 1: and eventually find a vaccine. Since nobody knew exactly what
Speaker 1: was causing the disease, they worked on three theories simultaneously.
Speaker 1: One was that it was being caused by an unknown virus,
Speaker 1: the next was that it was being caused by bacteria,
Speaker 1: possibly strapped UH, and the third was that it was
Speaker 1: being caused by herpes. This was a long shot to
Speaker 1: begin with because no causative agent had been found for
Speaker 1: this disease. They were basically operating in the dark based
Speaker 1: on best guesses. On top of that, there was a
Speaker 1: ton of infighting among the researchers. A lot of them
Speaker 1: were extremely prominent neurologists and scientists. Each of them really
Speaker 1: wanted to be the one to crack this case and
Speaker 1: figure out what's going on. Um that they were not
Speaker 1: working together very well. They were each trying to get
Speaker 1: the glory for themselves. And then there was another huge
Speaker 1: setback when Matheson himself died in nineteen thirty. That was
Speaker 1: in the middle of the Great Depression, and he had
Speaker 1: been providing the funding, so after his death there wasn't
Speaker 1: really other funding to be had, so the Matheson Commission
Speaker 1: ceased operations in ninety two and so no workable vaccine
Speaker 1: had been developed, and one of the things that doctors
Speaker 1: tried to treat post encephalitist patients of was lobotomies, which
Speaker 1: also did not work. There was a lot of ending
Speaker 1: that did not work. There were a few outlying successes
Speaker 1: during this time that would kind of give people false
Speaker 1: hope that maybe they were on the right track, but
Speaker 1: nothing led to an actual treatment or cure. Most of
Speaker 1: the medical care that the patients were receiving was really
Speaker 1: about just caring for their bodies and keeping them alive.
Speaker 1: The thirty or so percent who developed parkinson Is um
Speaker 1: generally wound up in long term care for the rest
Speaker 1: of their lives, and many of them were completely unable
Speaker 1: to move or take care of themselves. In the nineteen sixties,
Speaker 1: after the drug leve Adopa, or el dopa as it
Speaker 1: was called, was introduced for treating Parkinson's, New York doctor
Speaker 1: Oliver Sacks, who are some of our listeners may have
Speaker 1: heard of, administered it to some encephalitis lethargica patients who
Speaker 1: were in long term care. Some patients actually showed a
Speaker 1: limited recovery from their post and sephalitis lethargica parkinson symptoms.
Speaker 1: This is the story that's actually told in the movie Awakenings,
Speaker 1: which is why people may have heard of Olliver sex.
Speaker 1: But they all apparently developed a tolerance until the dosage
Speaker 1: was really just too much for the human body to handle,
Speaker 1: and then they would return to their semi comatose state
Speaker 1: in the end. This epidemic went on from nineteen sixteen
Speaker 1: to nineteen twenty seven, reaching its peak in nineteen twenty four,
Speaker 1: after which the number of cases started to drop off.
Speaker 1: The total numbers of people affected are really unclear. There
Speaker 1: are sources who say that a million people were killed,
Speaker 1: while others say that only half a million were affected
Speaker 1: in one way or another. Regardless, though the mortality rate
Speaker 1: was pretty serious in England, almost half of the cases
Speaker 1: in nineteen nineteen and nineteen twenty died. Although it was
Speaker 1: roughly concurrent with the Spanish flu pandemic, and flu came
Speaker 1: up frequently when looking at possible causes. Many doctors at
Speaker 1: the time didn't really think the disease was actually flu related.
Speaker 1: Only a small percentage of the patients had also had
Speaker 1: Spanish flu. In nineteen eighty two, however, doctors from the
Speaker 1: Centers for Disease Control published this list of connections between
Speaker 1: the two diseases. So for a little while. In more
Speaker 1: recent years, flu became a prime suspect for causing encephalitis lethargica.
Speaker 1: Uh there is, you know, especially since there have been
Speaker 1: other incidents of encephalitis that have followed outbreaks of the flu. Today,
Speaker 1: the idea that the flu was the culprit has pretty
Speaker 1: much been ruled out. Thanks to modern testing methods. They
Speaker 1: haven't turned up any sign of the flu virus in
Speaker 1: tissue samples from patients who died from encephalitis. Although it's
Speaker 1: never reached that same epidemic state again, isolated cases of
Speaker 1: encephalitis lethargica have continued to crop up even in recent years.
Speaker 1: Most recently in a twenty three year old named Becky
Speaker 1: Powell was diagnosed with the disease and it took her
Speaker 1: two years to recover. Several similar ass followed. In two
Speaker 1: thousand three, a team of doctors published a paper in
Speaker 1: the journal Brain that put forth a pretty good case
Speaker 1: that the cause of encephalitis lethargica is actually a massive
Speaker 1: autoimmune reaction to an unidentified pathogen. A strain of strep
Speaker 1: comes up in the discussion, but it's ultimately dismissed as unlikely.
Speaker 1: And their research was done on twenty different patients who
Speaker 1: developed the disease between two thousand two, and those patients
Speaker 1: had a much lower mortality rate than during the epidemic.
Speaker 1: Only one died, but five of them did have to
Speaker 1: be placed on a ventilator. Had those five patients lived
Speaker 1: in the ninety twenties, they probably would not have made it,
Speaker 1: but almost none of them had fully recovered a year
Speaker 1: or so later when the paper was published. They continued
Speaker 1: to have neurological and psychiatric symptoms. Yeah. If if there
Speaker 1: had been if today's ventilation technology had existed in the
Speaker 1: nineteen twenties, the mortality rate would have been sign Yeah,
Speaker 1: because people would get into this just deep uninterrupted sleep
Speaker 1: and their respiratory functions would fail, and there wasn't really
Speaker 1: anything that people could do about it. But now that
Speaker 1: we have ventilators, uh, that there are actual there's a
Speaker 1: treatment for that part of it that didn't exist back then.
Speaker 1: In a paper in the journal BMC Infectious Diseases reported
Speaker 1: that a team of researchers had found virus like particles
Speaker 1: in the brains of both epidemic encephalitis patients and modern patients,
Speaker 1: so people who had died either recently or during the epidemic.
Speaker 1: This supports the idea that the cause of encephalitis lethargica
Speaker 1: is an interarovirus, but exactly what interarovirus we still do
Speaker 1: you not know. So encephalitis lethargica has a some you know,
Speaker 1: a legacy today, even though a lot of people have
Speaker 1: not really heard of it as tragic and frightening as
Speaker 1: the disease was and is really. In the end, it
Speaker 1: helped doctors understand more about the brain. Von economos conclusion
Speaker 1: about the hypothalamus and its role in the patient's sleep,
Speaker 1: for example, was hugely unpopular at the time, but many
Speaker 1: years later it was proved to be true after we
Speaker 1: developed sorts of imaging technologies that we can use to
Speaker 1: look directly at the brain as it's working today. Neurologist
Speaker 1: Bernard Sacks also wrote that the epidemic of encephalitis quote
Speaker 1: revolutionized the practice of neurology, So it really changed the
Speaker 1: way that, uh, these things were examined from the get go. Yeah,
Speaker 1: it helped solidifying neurology as an actual field. In the
Speaker 1: early days, there was sort of this hodgepodge of neurology
Speaker 1: ideas and psychology ideas and all these things that were
Speaker 1: kind of together in one big pot. And in part
Speaker 1: because of encephalitis being spread the way that it was,
Speaker 1: a group of doctors branched off to study just neurology
Speaker 1: and it celf lightest lethargica was also one of the
Speaker 1: conditions that made it clear that disease processes can lead
Speaker 1: to mental illnesses. Uh, it's solidified the idea that mental
Speaker 1: illnesses were not solely in the realm of emotions or
Speaker 1: traumatic experiences. It's not always buried memories. Sometimes there can
Speaker 1: actually be a physical happening that causes mental illness. There
Speaker 1: are a couple of books that are out about this epidemic.
Speaker 1: The one that I read researching this podcast was called Asleep,
Speaker 1: The Forgotten Epidemic That Remains one of Medicine's Greatest Mysteries
Speaker 1: by Molly Caldwell Crosby and her grandmother survived sleepy sickness.
Speaker 1: It starts with sort of a case study of her grandmother.
Speaker 1: That's terrifying because it's about her grandmother being asleep for
Speaker 1: so long but also being aware of what was happening
Speaker 1: around her, which to me is just terrifying. The one
Speaker 1: caveat about this book is that it was written before
Speaker 1: the very most recent research about what might have caused
Speaker 1: this particular epidemic, which is going to be the case
Speaker 1: with just about every book now since the latest research
Speaker 1: is just from very new Yeah. Last year, as we
Speaker 1: were recording, I have read several papers that you know,
Speaker 1: and when the bird flu epidemic was was everybody was
Speaker 1: very frightened about bird flu. There were several articles that
Speaker 1: that came up where doctors were like, actually, what you
Speaker 1: really should be afraid of is a resurgence of this
Speaker 1: still unidentified encephalitis that sometimes that sometimes follows outbreaks of
Speaker 1: other diseases. I yeah, it's basically my worst nightmare. I mean,
Speaker 1: I have not a good relationship with sleep anyway. If
Speaker 1: I didn't have to do it, I wouldn't. So the
Speaker 1: idea of not having any control over the situation and
Speaker 1: just being asleep but not really because you're conscious of
Speaker 1: things happening. Is my worst nightmare. Yeah, not play on
Speaker 1: sleep jokes, but well, it's terrifying and the there are
Speaker 1: many things about this whole the epidemic and the illness
Speaker 1: itself that are are frightening to me, and one of
Speaker 1: them is that people would seem to recover and they
Speaker 1: would be fine for a long time, and then the
Speaker 1: developed fine developed parkinson symptoms um and once it had
Speaker 1: been established that that was a pattern, I can imagine
Speaker 1: like the people who had gotten better really being like
Speaker 1: I'm never going to be which I know that's the
Speaker 1: case with a lot of diseases that people have now,
Speaker 1: Like there are many cancer patients who never feel like
Speaker 1: they are in the clear because you can be in remission.
Speaker 1: So yeah, it's a scary thing to live with that
Speaker 1: kind of over you. Thank you so much for joining
Speaker 1: us on this Saturday. If you have heard an email
Speaker 1: address or a Facebook you are l or something similar
Speaker 1: over the course of today's episode, since it is from
Speaker 1: the archive that might be out of date now, you
Speaker 1: can email us at History Podcast at how Stuff Works
Speaker 1: dot com, and you can find us all over social
Speaker 1: media at missed in history, and you can subscribe to
Speaker 1: our show on Apple Podcasts, Google podcast, the I Heart
Speaker 1: Radio app, and wherever else you listen to podcasts. For
Speaker 1: more on this and thousands of other topics, visit how
Speaker 1: Stuff Works dot com. I'm Stuff you Should Know as
Speaker 1: Josh Clark, I'm launching a ten part podcast series about
Speaker 1: all the ways humanity might accidentally wipe ourselves right out
Speaker 1: of existence. It covers everything from whether we're alone in
Speaker 1: the universe to the evolution of life on Earth, from
Speaker 1: artificial intelligence to what goes on inside a particle collider.
Speaker 1: It is in a mensely interesting deep dive into the
Speaker 1: world of existential risks, and I hope that you enjoy
Speaker 1: listening to it as much as I have making it.
Speaker 1: I want to share a preview of the series with you.
Speaker 1: This clip comes from episode four and it features economist
Speaker 1: Robin Hansen, creator of the Great Filter hypothesis, which is
Speaker 1: something we may have to contend with in the near future.
Speaker 1: When we settled down, our cities, developed agriculture can support
Speaker 1: more people than hunting and gathering, and the more people
Speaker 1: there are, the more brilliant ideas there are. Two so
Speaker 1: our civilization began to advance by leaps and bounds in
Speaker 1: the last nine or ten thousand years. Ideas spread more
Speaker 1: quickly among those people who lived together in those new cities,
Speaker 1: so innovations were able to develop over the span of
Speaker 1: a handful of years rather than millennia. Almost everything we
Speaker 1: have in the world today can be traced back to
Speaker 1: our collective decision to settle down and raise crops. It was,
Speaker 1: to say the least, a sweeping change for us humans.
Speaker 1: With our next great leap spreading out into space, we
Speaker 1: are effectively doing the opposite of when we settled down
Speaker 1: into cities. Rather than contracting, we will be expanding. From
Speaker 1: that huge coming together, we will spread out. Over time,
Speaker 1: humans will begin to colonize other planets, and generations of
Speaker 1: little human babies will be borne on planets other than Earth.
Speaker 1: They will be shaped by forces and experiences that no
Speaker 1: earthbound human will have ever encountered, and they will learn
Speaker 1: to adapt to their home planet just like we did.
Speaker 1: We are quite capable of becoming all the things that
Speaker 1: it's possible to become. Life that starts from us and
Speaker 1: radiates out cannot only spread to different places that can
Speaker 1: create different styles and techniques and cultures and approaches. All
Speaker 1: of the life that you see on Earth started out
Speaker 1: from a much smaller amount of variation, but with time
Speaker 1: it could explore lots of different niches and ways of living.
Speaker 1: And that's probably what would happen to us too. If
Speaker 1: we're the only life around it, we can survive, we
Speaker 1: will radiate. We will become diverse and different and fill
Speaker 1: thousand million billion different niches of different ways of being.
Speaker 1: Over time, perhaps their physical connection to humans on Earth
Speaker 1: will become distant enough that new species of humans will form,
Speaker 1: and the universe will be home to more than one
Speaker 1: species of human again, just as it was fifty years ago.
Speaker 1: We will become the aliens we seek, and later on
Speaker 1: they might be surprised to learn that they came from
Speaker 1: something that was simple and not as very It's odd
Speaker 1: to think of, but humans are in an evolutionary bottleneck
Speaker 1: of our own. Right now. There's only one species of us,
Speaker 1: and with the exception of maybe half a dozen astronauts
Speaker 1: on the International Space Station at any given time, we
Speaker 1: are all stranded on this island Earth. Those astronauts aboard
Speaker 1: the I s S showed just the faintous beginnings of
Speaker 1: our future. If we become a space faring species, all
Speaker 1: of humanities eggs will no longer be in just the
Speaker 1: one basket of Earth. Should some catastrophe befall those of
Speaker 1: us here on Earth, there will be other humans living
Speaker 1: elsewhere to carry on. We will begin to trickle from
Speaker 1: our bottleneck and spread throughout the universe, and when we do,
Speaker 1: we will have made it through the great Filter. Colonizing
Speaker 1: beyond Earth is something we should begin working on as
Speaker 1: soon as we can, because Earth is vulnerable to a
Speaker 1: wide variety of catastrophes that are pretty hostile to life,
Speaker 1: things like exploding stars, the death of our son, even
Speaker 1: Earth's own systems going haywire. Please join me for the
Speaker 1: End of the World with Josh Clark. Listen and subscribe
Speaker 1: at Apple Podcasts or on the I Heart Radio app,
Speaker 1: or listen wherever you get your podcasts.