[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.34,0:00:02.38,Default,,0000,0000,0000,,So, I have a strange career.
Dialogue: 0,0:00:02.40,0:00:05.52,Default,,0000,0000,0000,,I know it because people come up to me,\Nlike colleagues, and say,
Dialogue: 0,0:00:05.54,0:00:07.41,Default,,0000,0000,0000,,"Chris, you have a strange career."
Dialogue: 0,0:00:07.44,0:00:09.08,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:00:09.10,0:00:10.42,Default,,0000,0000,0000,,And I can see their point,
Dialogue: 0,0:00:10.44,0:00:14.98,Default,,0000,0000,0000,,because I started my career\Nas a theoretical nuclear physicist.
Dialogue: 0,0:00:15.00,0:00:19.16,Default,,0000,0000,0000,,And I was thinking about quarks\Nand gluons and heavy ion collisions,
Dialogue: 0,0:00:19.19,0:00:20.98,Default,,0000,0000,0000,,and I was only 14 years old --
Dialogue: 0,0:00:21.59,0:00:24.28,Default,,0000,0000,0000,,No, no, I wasn't 14 years old.
Dialogue: 0,0:00:25.24,0:00:26.98,Default,,0000,0000,0000,,But after that,
Dialogue: 0,0:00:27.80,0:00:29.74,Default,,0000,0000,0000,,I actually had my own lab
Dialogue: 0,0:00:29.76,0:00:31.88,Default,,0000,0000,0000,,in the Computational\NNeuroscience department,
Dialogue: 0,0:00:31.90,0:00:33.63,Default,,0000,0000,0000,,and I wasn't doing any neuroscience.
Dialogue: 0,0:00:33.65,0:00:36.58,Default,,0000,0000,0000,,Later, I would work\Non evolutionary genetics,
Dialogue: 0,0:00:36.61,0:00:38.56,Default,,0000,0000,0000,,and I would work on systems biology.
Dialogue: 0,0:00:38.58,0:00:41.25,Default,,0000,0000,0000,,But I'm going to tell you\Nabout something else today.
Dialogue: 0,0:00:41.27,0:00:45.53,Default,,0000,0000,0000,,I'm going to tell you\Nabout how I learned something about life.
Dialogue: 0,0:00:45.56,0:00:49.04,Default,,0000,0000,0000,,And I was actually a rocket scientist.
Dialogue: 0,0:00:49.06,0:00:51.36,Default,,0000,0000,0000,,I wasn't really a rocket scientist,
Dialogue: 0,0:00:51.39,0:00:55.74,Default,,0000,0000,0000,,but I was working\Nat the Jet Propulsion Laboratory
Dialogue: 0,0:00:55.77,0:00:58.40,Default,,0000,0000,0000,,in sunny California, where it's warm;
Dialogue: 0,0:00:58.43,0:01:02.28,Default,,0000,0000,0000,,whereas now I am\Nin the mid-West, and it's cold.
Dialogue: 0,0:01:02.30,0:01:04.98,Default,,0000,0000,0000,,But it was an exciting experience.
Dialogue: 0,0:01:05.00,0:01:08.44,Default,,0000,0000,0000,,One day, a NASA manager\Ncomes into my office,
Dialogue: 0,0:01:08.47,0:01:10.98,Default,,0000,0000,0000,,sits down and says,
Dialogue: 0,0:01:11.60,0:01:15.40,Default,,0000,0000,0000,,"Can you please tell us,\Nhow do we look for life outside Earth?"
Dialogue: 0,0:01:16.36,0:01:18.04,Default,,0000,0000,0000,,And that came as a surprise to me,
Dialogue: 0,0:01:18.06,0:01:21.70,Default,,0000,0000,0000,,because I was actually hired\Nto work on quantum computation.
Dialogue: 0,0:01:22.21,0:01:23.71,Default,,0000,0000,0000,,Yet, I had a very good answer.
Dialogue: 0,0:01:23.74,0:01:25.16,Default,,0000,0000,0000,,I said, "I have no idea."
Dialogue: 0,0:01:25.54,0:01:26.69,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:01:26.71,0:01:32.06,Default,,0000,0000,0000,,And he told me, "Biosignatures,\Nwe need to look for a biosignature."
Dialogue: 0,0:01:32.08,0:01:33.44,Default,,0000,0000,0000,,And I said, "What is that?"
Dialogue: 0,0:01:33.47,0:01:36.06,Default,,0000,0000,0000,,And he said, "It's any\Nmeasurable phenomenon
Dialogue: 0,0:01:36.09,0:01:38.93,Default,,0000,0000,0000,,that allows us to indicate\Nthe presence of life."
Dialogue: 0,0:01:39.53,0:01:40.68,Default,,0000,0000,0000,,And I said, "Really?
Dialogue: 0,0:01:41.17,0:01:43.12,Default,,0000,0000,0000,,Because isn't that easy?
Dialogue: 0,0:01:43.14,0:01:44.98,Default,,0000,0000,0000,,I mean, we have life.
Dialogue: 0,0:01:44.100,0:01:46.97,Default,,0000,0000,0000,,Can't you apply a definition,
Dialogue: 0,0:01:46.100,0:01:51.17,Default,,0000,0000,0000,,for example, a Supreme Court-like\Ndefinition of life?"
Dialogue: 0,0:01:51.93,0:01:54.47,Default,,0000,0000,0000,,And then I thought about it\Na little bit, and I said,
Dialogue: 0,0:01:54.50,0:01:55.97,Default,,0000,0000,0000,,"Well, is it really that easy?
Dialogue: 0,0:01:55.100,0:01:58.19,Default,,0000,0000,0000,,Because, yes, if you see\Nsomething like this,
Dialogue: 0,0:01:58.21,0:02:00.56,Default,,0000,0000,0000,,then all right, fine,\NI'm going to call it life --
Dialogue: 0,0:02:00.58,0:02:01.73,Default,,0000,0000,0000,,no doubt about it.
Dialogue: 0,0:02:02.26,0:02:03.90,Default,,0000,0000,0000,,But here's something."
Dialogue: 0,0:02:03.92,0:02:06.98,Default,,0000,0000,0000,,And he goes, "Right,\Nthat's life too. I know that."
Dialogue: 0,0:02:07.00,0:02:11.59,Default,,0000,0000,0000,,Except, if you think that life\Nis also defined by things that die,
Dialogue: 0,0:02:11.62,0:02:13.37,Default,,0000,0000,0000,,you're not in luck with this thing,
Dialogue: 0,0:02:13.39,0:02:15.66,Default,,0000,0000,0000,,because that's actually\Na very strange organism.
Dialogue: 0,0:02:15.68,0:02:17.73,Default,,0000,0000,0000,,It grows up into the adult stage like that
Dialogue: 0,0:02:17.75,0:02:19.98,Default,,0000,0000,0000,,and then goes through\Na Benjamin Button phase,
Dialogue: 0,0:02:20.00,0:02:24.94,Default,,0000,0000,0000,,and actually goes backwards and backwards\Nuntil it's like a little embryo again,
Dialogue: 0,0:02:24.96,0:02:27.87,Default,,0000,0000,0000,,and then actually grows back up,\Nand back down and back up --
Dialogue: 0,0:02:27.90,0:02:29.68,Default,,0000,0000,0000,,sort of yo-yo -- and it never dies.
Dialogue: 0,0:02:29.70,0:02:31.93,Default,,0000,0000,0000,,So it's actually life,
Dialogue: 0,0:02:31.95,0:02:35.98,Default,,0000,0000,0000,,but it's actually not\Nas we thought life would be.
Dialogue: 0,0:02:36.49,0:02:38.40,Default,,0000,0000,0000,,And then you see something like that.
Dialogue: 0,0:02:38.43,0:02:41.30,Default,,0000,0000,0000,,And he was like, "My God,\Nwhat kind of a life form is that?"
Dialogue: 0,0:02:41.32,0:02:42.74,Default,,0000,0000,0000,,Anyone know?
Dialogue: 0,0:02:42.77,0:02:45.77,Default,,0000,0000,0000,,It's actually not life, it's a crystal.
Dialogue: 0,0:02:46.28,0:02:49.58,Default,,0000,0000,0000,,So once you start looking and looking\Nat smaller and smaller things --
Dialogue: 0,0:02:49.61,0:02:52.77,Default,,0000,0000,0000,,so this particular person wrote\Na whole article and said,
Dialogue: 0,0:02:52.79,0:02:54.27,Default,,0000,0000,0000,,"Hey, these are bacteria."
Dialogue: 0,0:02:54.30,0:02:56.27,Default,,0000,0000,0000,,Except, if you look a little bit closer,
Dialogue: 0,0:02:56.29,0:02:59.93,Default,,0000,0000,0000,,you see, in fact, that this thing\Nis way too small to be anything like that.
Dialogue: 0,0:02:59.95,0:03:03.11,Default,,0000,0000,0000,,So he was convinced,\Nbut, in fact, most people aren't.
Dialogue: 0,0:03:03.79,0:03:06.98,Default,,0000,0000,0000,,And then, of course,\NNASA also had a big announcement,
Dialogue: 0,0:03:07.00,0:03:09.86,Default,,0000,0000,0000,,and President Clinton\Ngave a press conference,
Dialogue: 0,0:03:09.89,0:03:14.75,Default,,0000,0000,0000,,about this amazing discovery\Nof life in a Martian meteorite.
Dialogue: 0,0:03:15.40,0:03:18.36,Default,,0000,0000,0000,,Except that nowadays,\Nit's heavily disputed.
Dialogue: 0,0:03:18.81,0:03:21.24,Default,,0000,0000,0000,,If you take the lesson\Nof all these pictures,
Dialogue: 0,0:03:21.26,0:03:24.16,Default,,0000,0000,0000,,then you realize, well, actually,\Nmaybe it's not that easy.
Dialogue: 0,0:03:24.18,0:03:27.58,Default,,0000,0000,0000,,Maybe I do need a definition of life
Dialogue: 0,0:03:27.61,0:03:29.88,Default,,0000,0000,0000,,in order to make that kind of distinction.
Dialogue: 0,0:03:29.91,0:03:32.44,Default,,0000,0000,0000,,So can life be defined?
Dialogue: 0,0:03:32.46,0:03:33.97,Default,,0000,0000,0000,,Well how would you go about it?
Dialogue: 0,0:03:33.99,0:03:38.00,Default,,0000,0000,0000,,Well of course, you'd go\Nto Encyclopedia Britannica and open at L.
Dialogue: 0,0:03:38.02,0:03:41.04,Default,,0000,0000,0000,,No, of course you don't do that;\Nyou put it somewhere in Google.
Dialogue: 0,0:03:41.06,0:03:42.65,Default,,0000,0000,0000,,And then you might get something.
Dialogue: 0,0:03:42.68,0:03:43.70,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:03:43.72,0:03:44.94,Default,,0000,0000,0000,,And what you might get --
Dialogue: 0,0:03:44.97,0:03:48.74,Default,,0000,0000,0000,,and anything that actually refers\Nto things that we are used to,
Dialogue: 0,0:03:48.77,0:03:49.99,Default,,0000,0000,0000,,you throw away.
Dialogue: 0,0:03:50.02,0:03:52.51,Default,,0000,0000,0000,,And then you might come up\Nwith something like this.
Dialogue: 0,0:03:52.54,0:03:55.79,Default,,0000,0000,0000,,And it says something complicated\Nwith lots and lots of concepts.
Dialogue: 0,0:03:55.82,0:04:01.18,Default,,0000,0000,0000,,Who on Earth would write something\Nas convoluted and complex and inane?
Dialogue: 0,0:04:02.95,0:04:06.85,Default,,0000,0000,0000,,Oh, it's actually a really, really,\Nimportant set of concepts.
Dialogue: 0,0:04:06.88,0:04:08.98,Default,,0000,0000,0000,,So I'm highlighting just a few words
Dialogue: 0,0:04:09.00,0:04:12.92,Default,,0000,0000,0000,,and saying definitions\Nlike that rely on things
Dialogue: 0,0:04:12.95,0:04:19.10,Default,,0000,0000,0000,,that are not based on amino acids\Nor leaves or anything that we are used to,
Dialogue: 0,0:04:19.12,0:04:20.87,Default,,0000,0000,0000,,but in fact on processes only.
Dialogue: 0,0:04:20.90,0:04:22.77,Default,,0000,0000,0000,,And if you take a look at that,
Dialogue: 0,0:04:22.79,0:04:26.25,Default,,0000,0000,0000,,this was actually in a book that I wrote\Nthat deals with artificial life.
Dialogue: 0,0:04:26.27,0:04:30.50,Default,,0000,0000,0000,,And that explains why that NASA manager\Nwas actually in my office to begin with.
Dialogue: 0,0:04:30.52,0:04:33.61,Default,,0000,0000,0000,,Because the idea was that,\Nwith concepts like that,
Dialogue: 0,0:04:33.63,0:04:37.65,Default,,0000,0000,0000,,maybe we can actually\Nmanufacture a form of life.
Dialogue: 0,0:04:37.68,0:04:42.48,Default,,0000,0000,0000,,And so if you go and ask yourself,\N"What on Earth is artificial life?",
Dialogue: 0,0:04:42.50,0:04:46.17,Default,,0000,0000,0000,,let me give you a whirlwind tour\Nof how all this stuff came about.
Dialogue: 0,0:04:46.19,0:04:49.33,Default,,0000,0000,0000,,And it started out quite a while ago,
Dialogue: 0,0:04:49.35,0:04:53.68,Default,,0000,0000,0000,,when someone wrote one of the first\Nsuccessful computer viruses.
Dialogue: 0,0:04:53.98,0:04:56.16,Default,,0000,0000,0000,,And for those of you\Nwho aren't old enough,
Dialogue: 0,0:04:56.18,0:04:58.76,Default,,0000,0000,0000,,you have no idea\Nhow this infection was working --
Dialogue: 0,0:04:58.79,0:05:01.05,Default,,0000,0000,0000,,namely, through these floppy disks.
Dialogue: 0,0:05:01.07,0:05:04.96,Default,,0000,0000,0000,,But the interesting thing\Nabout these computer virus infections
Dialogue: 0,0:05:04.98,0:05:08.44,Default,,0000,0000,0000,,was that, if you look at the rate\Nat which the infection worked,
Dialogue: 0,0:05:08.46,0:05:12.61,Default,,0000,0000,0000,,they show this spiky behavior\Nthat you're used to from a flu virus.
Dialogue: 0,0:05:12.63,0:05:14.98,Default,,0000,0000,0000,,And it is in fact due to this arms race
Dialogue: 0,0:05:15.00,0:05:18.46,Default,,0000,0000,0000,,between hackers\Nand operating system designers
Dialogue: 0,0:05:18.48,0:05:20.08,Default,,0000,0000,0000,,that things go back and forth.
Dialogue: 0,0:05:20.10,0:05:24.62,Default,,0000,0000,0000,,And the result is kind of\Na tree of life of these viruses,
Dialogue: 0,0:05:24.64,0:05:28.24,Default,,0000,0000,0000,,a phylogeny that looks very much\Nlike the type of life
Dialogue: 0,0:05:28.27,0:05:30.70,Default,,0000,0000,0000,,that we're used to,\Nat least on the viral level.
Dialogue: 0,0:05:30.72,0:05:32.05,Default,,0000,0000,0000,,So is that life?
Dialogue: 0,0:05:32.27,0:05:33.88,Default,,0000,0000,0000,,Not as far as I'm concerned.
Dialogue: 0,0:05:33.91,0:05:36.75,Default,,0000,0000,0000,,Why? Because these things\Ndon't evolve by themselves.
Dialogue: 0,0:05:36.77,0:05:38.72,Default,,0000,0000,0000,,In fact, they have hackers writing them.
Dialogue: 0,0:05:38.75,0:05:42.08,Default,,0000,0000,0000,,But the idea was taken\Nvery quickly a little bit further,
Dialogue: 0,0:05:42.10,0:05:45.41,Default,,0000,0000,0000,,when a scientist working\Nat the Santa Fe Institute decided,
Dialogue: 0,0:05:45.44,0:05:48.57,Default,,0000,0000,0000,,"Why don't we try to package\Nthese little viruses
Dialogue: 0,0:05:48.60,0:05:50.81,Default,,0000,0000,0000,,in artificial worlds\Ninside of the computer
Dialogue: 0,0:05:50.83,0:05:52.10,Default,,0000,0000,0000,,and let them evolve?"
Dialogue: 0,0:05:52.13,0:05:53.72,Default,,0000,0000,0000,,And this was Steen Rasmussen.
Dialogue: 0,0:05:53.75,0:05:56.44,Default,,0000,0000,0000,,And he designed this system,\Nbut it really didn't work,
Dialogue: 0,0:05:56.46,0:05:59.35,Default,,0000,0000,0000,,because his viruses\Nwere constantly destroying each other.
Dialogue: 0,0:05:59.37,0:06:02.89,Default,,0000,0000,0000,,But there was another scientist\Nwho had been watching this, an ecologist.
Dialogue: 0,0:06:02.91,0:06:05.40,Default,,0000,0000,0000,,And he went home and says,\N"I know how to fix this."
Dialogue: 0,0:06:05.43,0:06:07.07,Default,,0000,0000,0000,,And he wrote the Tierra system,
Dialogue: 0,0:06:07.10,0:06:08.30,Default,,0000,0000,0000,,and, in my book,
Dialogue: 0,0:06:08.32,0:06:12.15,Default,,0000,0000,0000,,is in fact one of the first\Ntruly artificial living systems --
Dialogue: 0,0:06:12.17,0:06:15.64,Default,,0000,0000,0000,,except for the fact that these programs\Ndidn't really grow in complexity.
Dialogue: 0,0:06:15.66,0:06:18.52,Default,,0000,0000,0000,,So having seen this work,\Nworked a little bit on this,
Dialogue: 0,0:06:18.55,0:06:20.20,Default,,0000,0000,0000,,this is where I came in.
Dialogue: 0,0:06:20.23,0:06:23.87,Default,,0000,0000,0000,,And I decided to create a system\Nthat has all the properties
Dialogue: 0,0:06:23.90,0:06:27.74,Default,,0000,0000,0000,,that are necessary to see, in fact,\Nthe evolution of complexity,
Dialogue: 0,0:06:27.77,0:06:31.07,Default,,0000,0000,0000,,more and more complex\Nproblems constantly evolving.
Dialogue: 0,0:06:31.09,0:06:34.88,Default,,0000,0000,0000,,And of course, since I really don't know\Nhow to write code, I had help in this.
Dialogue: 0,0:06:34.90,0:06:36.45,Default,,0000,0000,0000,,I had two undergraduate students
Dialogue: 0,0:06:36.47,0:06:39.20,Default,,0000,0000,0000,,at California Institute of Technology\Nthat worked with me.
Dialogue: 0,0:06:39.22,0:06:42.08,Default,,0000,0000,0000,,That's Charles Ofria on the left,\NTitus Brown on the right.
Dialogue: 0,0:06:42.10,0:06:44.44,Default,,0000,0000,0000,,They are now, actually,\Nrespectable professors
Dialogue: 0,0:06:44.46,0:06:46.20,Default,,0000,0000,0000,,at Michigan State University,
Dialogue: 0,0:06:46.23,0:06:50.73,Default,,0000,0000,0000,,but I can assure you, back in the day,\Nwe were not a respectable team.
Dialogue: 0,0:06:50.75,0:06:52.80,Default,,0000,0000,0000,,And I'm really happy\Nthat no photo survives
Dialogue: 0,0:06:52.82,0:06:55.35,Default,,0000,0000,0000,,of the three of us\Nanywhere close together.
Dialogue: 0,0:06:56.09,0:06:57.97,Default,,0000,0000,0000,,But what is this system like?
Dialogue: 0,0:06:57.99,0:07:00.18,Default,,0000,0000,0000,,Well I can't really go into the details,
Dialogue: 0,0:07:00.20,0:07:02.86,Default,,0000,0000,0000,,but what you see here\Nis some of the entrails.
Dialogue: 0,0:07:02.88,0:07:06.97,Default,,0000,0000,0000,,But what I wanted to focus on\Nis this type of population structure.
Dialogue: 0,0:07:06.99,0:07:09.46,Default,,0000,0000,0000,,There's about 10,000\Nprograms sitting here.
Dialogue: 0,0:07:09.49,0:07:12.40,Default,,0000,0000,0000,,And all different strains\Nare colored in different colors.
Dialogue: 0,0:07:12.43,0:07:16.03,Default,,0000,0000,0000,,And as you see here, there are groups\Nthat are growing on top of each other,
Dialogue: 0,0:07:16.06,0:07:17.40,Default,,0000,0000,0000,,because they are spreading.
Dialogue: 0,0:07:17.42,0:07:21.53,Default,,0000,0000,0000,,Any time there is a program\Nthat's better at surviving in this world,
Dialogue: 0,0:07:21.55,0:07:23.52,Default,,0000,0000,0000,,due to whatever mutation it has acquired,
Dialogue: 0,0:07:23.54,0:07:27.01,Default,,0000,0000,0000,,it is going to spread over the others\Nand drive the others to extinction.
Dialogue: 0,0:07:27.04,0:07:28.59,Default,,0000,0000,0000,,So I'm going to show you a movie
Dialogue: 0,0:07:28.62,0:07:30.84,Default,,0000,0000,0000,,where you're going to see\Nthat kind of dynamic.
Dialogue: 0,0:07:30.87,0:07:35.14,Default,,0000,0000,0000,,And these kinds of experiments are started\Nwith programs that we wrote ourselves.
Dialogue: 0,0:07:35.17,0:07:38.50,Default,,0000,0000,0000,,We write our own stuff, replicate it,\Nand are very proud of ourselves.
Dialogue: 0,0:07:38.53,0:07:41.30,Default,,0000,0000,0000,,And we put them in,\Nand what you see immediately
Dialogue: 0,0:07:41.33,0:07:44.39,Default,,0000,0000,0000,,is that there are waves\Nand waves of innovation.
Dialogue: 0,0:07:44.42,0:07:46.31,Default,,0000,0000,0000,,By the way, this is highly accelerated,
Dialogue: 0,0:07:46.34,0:07:48.53,Default,,0000,0000,0000,,so it's like a 1000 generations a second.
Dialogue: 0,0:07:48.56,0:07:52.52,Default,,0000,0000,0000,,But immediately, the system goes like,\N"What kind of dumb piece of code was this?
Dialogue: 0,0:07:52.55,0:07:56.27,Default,,0000,0000,0000,,This can be improved upon\Nin so many ways, so quickly."
Dialogue: 0,0:07:56.29,0:08:00.04,Default,,0000,0000,0000,,So you see waves of new types\Ntaking over the other types.
Dialogue: 0,0:08:00.06,0:08:02.63,Default,,0000,0000,0000,,And this type of activity\Ngoes on for quite a while,
Dialogue: 0,0:08:02.65,0:08:07.47,Default,,0000,0000,0000,,until the main easy things\Nhave been acquired by these programs.
Dialogue: 0,0:08:07.50,0:08:10.98,Default,,0000,0000,0000,,And then, you see\Nsort of like a stasis coming on
Dialogue: 0,0:08:11.00,0:08:12.98,Default,,0000,0000,0000,,where the system essentially waits
Dialogue: 0,0:08:13.00,0:08:16.18,Default,,0000,0000,0000,,for a new type of innovation,\Nlike this one,
Dialogue: 0,0:08:16.21,0:08:20.49,Default,,0000,0000,0000,,which is going to spread over\Nall the other innovations that were before
Dialogue: 0,0:08:20.51,0:08:22.98,Default,,0000,0000,0000,,and is erasing the genes\Nthat it had before,
Dialogue: 0,0:08:23.00,0:08:26.98,Default,,0000,0000,0000,,until a new type of higher level\Nof complexity has been achieved.
Dialogue: 0,0:08:27.00,0:08:29.98,Default,,0000,0000,0000,,And this process goes on and on and on.
Dialogue: 0,0:08:30.47,0:08:31.78,Default,,0000,0000,0000,,So what we see here
Dialogue: 0,0:08:31.81,0:08:35.97,Default,,0000,0000,0000,,is a system that lives in very much\Nthe way we're used to how life goes.
Dialogue: 0,0:08:36.69,0:08:40.81,Default,,0000,0000,0000,,But what the NASA people\Nhad asked me really was,
Dialogue: 0,0:08:41.21,0:08:43.98,Default,,0000,0000,0000,,"Do these guys have a biosignature?
Dialogue: 0,0:08:44.58,0:08:46.39,Default,,0000,0000,0000,,Can we measure this type of life?
Dialogue: 0,0:08:46.42,0:08:47.61,Default,,0000,0000,0000,,Because if we can,
Dialogue: 0,0:08:47.63,0:08:51.48,Default,,0000,0000,0000,,maybe we have a chance of actually\Ndiscovering life somewhere else
Dialogue: 0,0:08:51.51,0:08:54.66,Default,,0000,0000,0000,,without being biased\Nby things like amino acids."
Dialogue: 0,0:08:55.22,0:08:59.75,Default,,0000,0000,0000,,So I said, "Well, perhaps\Nwe should construct a biosignature
Dialogue: 0,0:08:59.78,0:09:02.98,Default,,0000,0000,0000,,based on life as a universal process.
Dialogue: 0,0:09:03.00,0:09:07.86,Default,,0000,0000,0000,,In fact, it should perhaps make use\Nof the concepts that I developed
Dialogue: 0,0:09:07.89,0:09:11.98,Default,,0000,0000,0000,,just in order to sort of capture\Nwhat a simple living system might be."
Dialogue: 0,0:09:11.100,0:09:13.52,Default,,0000,0000,0000,,And the thing I came up with --
Dialogue: 0,0:09:13.54,0:09:17.52,Default,,0000,0000,0000,,I have to first give you\Nan introduction about the idea,
Dialogue: 0,0:09:17.55,0:09:21.09,Default,,0000,0000,0000,,and maybe that would be\Na meaning detector,
Dialogue: 0,0:09:21.11,0:09:22.66,Default,,0000,0000,0000,,rather than a life detector.
Dialogue: 0,0:09:23.23,0:09:24.98,Default,,0000,0000,0000,,And the way we would do that --
Dialogue: 0,0:09:25.00,0:09:27.64,Default,,0000,0000,0000,,I would like to find out\Nhow I can distinguish text
Dialogue: 0,0:09:27.66,0:09:32.31,Default,,0000,0000,0000,,that was written by a million monkeys,\Nas opposed to text that is in our books.
Dialogue: 0,0:09:32.64,0:09:34.52,Default,,0000,0000,0000,,And I would like to do it in such a way
Dialogue: 0,0:09:34.55,0:09:37.42,Default,,0000,0000,0000,,that I don't actually have to be able\Nto read the language,
Dialogue: 0,0:09:37.45,0:09:39.22,Default,,0000,0000,0000,,because I'm sure I won't be able to.
Dialogue: 0,0:09:39.24,0:09:41.74,Default,,0000,0000,0000,,As long as I know\Nthat there's some sort of alphabet.
Dialogue: 0,0:09:41.77,0:09:44.10,Default,,0000,0000,0000,,So here would be a frequency plot
Dialogue: 0,0:09:44.12,0:09:47.50,Default,,0000,0000,0000,,of how often you find\Neach of the 26 letters of the alphabet
Dialogue: 0,0:09:47.53,0:09:49.74,Default,,0000,0000,0000,,in a text written by random monkeys.
Dialogue: 0,0:09:50.20,0:09:54.75,Default,,0000,0000,0000,,And obviously, each of these letters\Ncomes off about roughly equally frequent.
Dialogue: 0,0:09:54.77,0:09:58.36,Default,,0000,0000,0000,,But if you now look at the same\Ndistribution in English texts,
Dialogue: 0,0:09:58.39,0:09:59.64,Default,,0000,0000,0000,,it looks like that.
Dialogue: 0,0:10:00.20,0:10:03.75,Default,,0000,0000,0000,,And I'm telling you,\Nthis is very robust across English texts.
Dialogue: 0,0:10:03.77,0:10:06.76,Default,,0000,0000,0000,,And if I look at French texts,\Nit looks a little bit different,
Dialogue: 0,0:10:06.78,0:10:07.96,Default,,0000,0000,0000,,or Italian or German.
Dialogue: 0,0:10:07.98,0:10:11.40,Default,,0000,0000,0000,,They all have their own type\Nof frequency distribution,
Dialogue: 0,0:10:11.42,0:10:12.86,Default,,0000,0000,0000,,but it's robust.
Dialogue: 0,0:10:12.88,0:10:16.09,Default,,0000,0000,0000,,It doesn't matter whether it writes\Nabout politics or about science.
Dialogue: 0,0:10:16.11,0:10:21.89,Default,,0000,0000,0000,,It doesn't matter whether it's a poem\Nor whether it's a mathematical text.
Dialogue: 0,0:10:21.92,0:10:23.75,Default,,0000,0000,0000,,It's a robust signature,
Dialogue: 0,0:10:23.78,0:10:25.60,Default,,0000,0000,0000,,and it's very stable.
Dialogue: 0,0:10:25.62,0:10:27.78,Default,,0000,0000,0000,,As long as our books\Nare written in English --
Dialogue: 0,0:10:27.80,0:10:30.59,Default,,0000,0000,0000,,because people are rewriting them\Nand recopying them --
Dialogue: 0,0:10:30.62,0:10:31.98,Default,,0000,0000,0000,,it's going to be there.
Dialogue: 0,0:10:32.00,0:10:37.76,Default,,0000,0000,0000,,So that inspired me to think about,\Nwell, what if I try to use this idea
Dialogue: 0,0:10:37.78,0:10:41.54,Default,,0000,0000,0000,,in order, not to detect random texts\Nfrom texts with meaning,
Dialogue: 0,0:10:41.56,0:10:45.29,Default,,0000,0000,0000,,but rather detect the fact\Nthat there is meaning
Dialogue: 0,0:10:45.32,0:10:47.84,Default,,0000,0000,0000,,in the biomolecules that make up life.
Dialogue: 0,0:10:47.87,0:10:49.04,Default,,0000,0000,0000,,But first I have to ask:
Dialogue: 0,0:10:49.06,0:10:50.55,Default,,0000,0000,0000,,what are these building blocks,
Dialogue: 0,0:10:50.57,0:10:52.87,Default,,0000,0000,0000,,like the alphabet, elements\Nthat I showed you?
Dialogue: 0,0:10:52.89,0:10:55.76,Default,,0000,0000,0000,,Well it turns out, we have\Nmany different alternatives
Dialogue: 0,0:10:55.79,0:10:58.10,Default,,0000,0000,0000,,for such a set of building blocks.
Dialogue: 0,0:10:58.13,0:10:59.38,Default,,0000,0000,0000,,We could use amino acids,
Dialogue: 0,0:10:59.40,0:11:02.60,Default,,0000,0000,0000,,we could use nucleic acids,\Ncarboxylic acids, fatty acids.
Dialogue: 0,0:11:02.62,0:11:06.06,Default,,0000,0000,0000,,In fact, chemistry's extremely rich,\Nand our body uses a lot of them.
Dialogue: 0,0:11:06.09,0:11:08.39,Default,,0000,0000,0000,,So that we actually, to test this idea,
Dialogue: 0,0:11:08.42,0:11:11.96,Default,,0000,0000,0000,,first took a look at amino acids\Nand some other carboxylic acids.
Dialogue: 0,0:11:11.99,0:11:13.46,Default,,0000,0000,0000,,And here's the result.
Dialogue: 0,0:11:13.48,0:11:16.65,Default,,0000,0000,0000,,Here is, in fact, what you get
Dialogue: 0,0:11:16.67,0:11:19.70,Default,,0000,0000,0000,,if you, for example, look\Nat the distribution of amino acids
Dialogue: 0,0:11:19.72,0:11:24.46,Default,,0000,0000,0000,,on a comet or in interstellar space\Nor, in fact, in a laboratory,
Dialogue: 0,0:11:24.48,0:11:27.14,Default,,0000,0000,0000,,where you made very sure\Nthat in your primordial soup,
Dialogue: 0,0:11:27.16,0:11:29.08,Default,,0000,0000,0000,,there is no living stuff in there.
Dialogue: 0,0:11:29.10,0:11:31.98,Default,,0000,0000,0000,,What you find is mostly\Nglycine and then alanine
Dialogue: 0,0:11:32.01,0:11:34.37,Default,,0000,0000,0000,,and there's some trace elements\Nof the other ones.
Dialogue: 0,0:11:34.39,0:11:36.82,Default,,0000,0000,0000,,That is also very robust --
Dialogue: 0,0:11:36.84,0:11:40.68,Default,,0000,0000,0000,,what you find in systems like Earth
Dialogue: 0,0:11:40.70,0:11:43.84,Default,,0000,0000,0000,,where there are amino acids,\Nbut there is no life.
Dialogue: 0,0:11:43.87,0:11:48.50,Default,,0000,0000,0000,,But suppose you take some dirt\Nand dig through it
Dialogue: 0,0:11:48.52,0:11:51.48,Default,,0000,0000,0000,,and then put it into these spectrometers,
Dialogue: 0,0:11:51.51,0:11:53.60,Default,,0000,0000,0000,,because there's bacteria\Nall over the place;
Dialogue: 0,0:11:53.63,0:11:55.86,Default,,0000,0000,0000,,or you take water anywhere on Earth,
Dialogue: 0,0:11:55.88,0:11:57.40,Default,,0000,0000,0000,,because it's teaming with life,
Dialogue: 0,0:11:57.42,0:11:59.17,Default,,0000,0000,0000,,and you make the same analysis;
Dialogue: 0,0:11:59.20,0:12:01.78,Default,,0000,0000,0000,,the spectrum looks completely different.
Dialogue: 0,0:12:01.80,0:12:05.17,Default,,0000,0000,0000,,Of course, there is still\Nglycine and alanine,
Dialogue: 0,0:12:05.20,0:12:08.52,Default,,0000,0000,0000,,but in fact, there are these heavy\Nelements, these heavy amino acids,
Dialogue: 0,0:12:08.54,0:12:11.94,Default,,0000,0000,0000,,that are being produced\Nbecause they are valuable to the organism.
Dialogue: 0,0:12:13.07,0:12:17.00,Default,,0000,0000,0000,,And some other ones\Nthat are not used in the set of 20,
Dialogue: 0,0:12:17.03,0:12:19.93,Default,,0000,0000,0000,,they will not appear at all\Nin any type of concentration.
Dialogue: 0,0:12:19.95,0:12:22.66,Default,,0000,0000,0000,,So this also turns out\Nto be extremely robust.
Dialogue: 0,0:12:22.68,0:12:25.80,Default,,0000,0000,0000,,It doesn't matter what kind of sediment\Nyou're using to grind up,
Dialogue: 0,0:12:25.82,0:12:29.10,Default,,0000,0000,0000,,whether it's bacteria\Nor any other plants or animals.
Dialogue: 0,0:12:29.12,0:12:30.55,Default,,0000,0000,0000,,Anywhere there's life,
Dialogue: 0,0:12:30.57,0:12:32.52,Default,,0000,0000,0000,,you're going to have this distribution,
Dialogue: 0,0:12:32.55,0:12:34.36,Default,,0000,0000,0000,,as opposed to that distribution.
Dialogue: 0,0:12:34.39,0:12:37.63,Default,,0000,0000,0000,,And it is detectable\Nnot just in amino acids.
Dialogue: 0,0:12:37.65,0:12:38.87,Default,,0000,0000,0000,,Now you could ask:
Dialogue: 0,0:12:38.89,0:12:42.05,Default,,0000,0000,0000,,Well, what about these Avidians?
Dialogue: 0,0:12:42.07,0:12:45.12,Default,,0000,0000,0000,,The Avidians being the denizens\Nof this computer world
Dialogue: 0,0:12:45.15,0:12:48.59,Default,,0000,0000,0000,,where they are perfectly happy\Nreplicating and growing in complexity.
Dialogue: 0,0:12:48.62,0:12:53.64,Default,,0000,0000,0000,,So this is the distribution that you get\Nif, in fact, there is no life.
Dialogue: 0,0:12:53.66,0:12:56.38,Default,,0000,0000,0000,,They have about 28 of these instructions.
Dialogue: 0,0:12:56.40,0:12:59.75,Default,,0000,0000,0000,,And if you have a system where\Nthey're being replaced one by the other,
Dialogue: 0,0:12:59.78,0:13:01.96,Default,,0000,0000,0000,,it's like the monkeys\Nwriting on a typewriter.
Dialogue: 0,0:13:01.99,0:13:06.21,Default,,0000,0000,0000,,Each of these instructions\Nappears with roughly the equal frequency.
Dialogue: 0,0:13:07.12,0:13:11.90,Default,,0000,0000,0000,,But if you now take\Na set of replicating guys
Dialogue: 0,0:13:11.92,0:13:13.87,Default,,0000,0000,0000,,like in the video that you saw,
Dialogue: 0,0:13:13.89,0:13:15.41,Default,,0000,0000,0000,,it looks like this.
Dialogue: 0,0:13:16.20,0:13:17.67,Default,,0000,0000,0000,,So there are some instructions
Dialogue: 0,0:13:17.70,0:13:20.13,Default,,0000,0000,0000,,that are extremely valuable\Nto these organisms,
Dialogue: 0,0:13:20.15,0:13:22.12,Default,,0000,0000,0000,,and their frequency is going to be high.
Dialogue: 0,0:13:22.15,0:13:26.19,Default,,0000,0000,0000,,And there's actually some instructions\Nthat you only use once, if ever.
Dialogue: 0,0:13:26.21,0:13:27.74,Default,,0000,0000,0000,,So they are either poisonous
Dialogue: 0,0:13:27.76,0:13:32.26,Default,,0000,0000,0000,,or really should be used\Nat less of a level than random.
Dialogue: 0,0:13:32.29,0:13:34.98,Default,,0000,0000,0000,,In this case, the frequency is lower.
Dialogue: 0,0:13:35.93,0:13:38.60,Default,,0000,0000,0000,,And so now we can see,\Nis that really a robust signature?
Dialogue: 0,0:13:38.63,0:13:39.98,Default,,0000,0000,0000,,I can tell you indeed it is,
Dialogue: 0,0:13:40.01,0:13:43.26,Default,,0000,0000,0000,,because this type of spectrum,\Njust like what you've seen in books,
Dialogue: 0,0:13:43.28,0:13:45.43,Default,,0000,0000,0000,,and just like what you've seen\Nin amino acids,
Dialogue: 0,0:13:45.46,0:13:48.10,Default,,0000,0000,0000,,it doesn't really matter\Nhow you change the environment,
Dialogue: 0,0:13:48.12,0:13:50.75,Default,,0000,0000,0000,,it's very robust, it's going\Nto reflect the environment.
Dialogue: 0,0:13:50.77,0:13:53.72,Default,,0000,0000,0000,,So I'm going to show you now\Na little experiment that we did.
Dialogue: 0,0:13:53.74,0:13:55.13,Default,,0000,0000,0000,,And I have to explain to you,
Dialogue: 0,0:13:55.15,0:13:56.33,Default,,0000,0000,0000,,the top of this graph
Dialogue: 0,0:13:56.36,0:13:59.10,Default,,0000,0000,0000,,shows you that frequency\Ndistribution that I talked about.
Dialogue: 0,0:13:59.13,0:14:02.93,Default,,0000,0000,0000,,Here, that's the lifeless environment
Dialogue: 0,0:14:02.96,0:14:06.37,Default,,0000,0000,0000,,where each instruction occurs\Nat an equal frequency.
Dialogue: 0,0:14:07.30,0:14:12.30,Default,,0000,0000,0000,,And below there, I show, in fact,\Nthe mutation rate in the environment.
Dialogue: 0,0:14:12.32,0:14:15.62,Default,,0000,0000,0000,,And I'm starting this\Nat a mutation rate that is so high
Dialogue: 0,0:14:15.65,0:14:19.61,Default,,0000,0000,0000,,that even if you would drop\Na replicating program
Dialogue: 0,0:14:19.64,0:14:23.76,Default,,0000,0000,0000,,that would otherwise happily grow up\Nto fill the entire world,
Dialogue: 0,0:14:23.79,0:14:26.80,Default,,0000,0000,0000,,if you drop it in, it gets mutated\Nto death immediately.
Dialogue: 0,0:14:26.82,0:14:32.17,Default,,0000,0000,0000,,So there is no life possible\Nat that type of mutation rate.
Dialogue: 0,0:14:32.19,0:14:36.23,Default,,0000,0000,0000,,But then I'm going to slowly\Nturn down the heat, so to speak,
Dialogue: 0,0:14:36.25,0:14:38.44,Default,,0000,0000,0000,,and then there's this viability threshold
Dialogue: 0,0:14:38.46,0:14:42.35,Default,,0000,0000,0000,,where now it would be possible\Nfor a replicator to actually live.
Dialogue: 0,0:14:42.38,0:14:47.72,Default,,0000,0000,0000,,And indeed, we're going to be dropping\Nthese guys into that soup all the time.
Dialogue: 0,0:14:48.16,0:14:49.80,Default,,0000,0000,0000,,So let's see what that looks like.
Dialogue: 0,0:14:49.82,0:14:52.82,Default,,0000,0000,0000,,So first, nothing, nothing, nothing.
Dialogue: 0,0:14:52.84,0:14:54.66,Default,,0000,0000,0000,,Too hot, too hot.
Dialogue: 0,0:14:54.68,0:14:56.98,Default,,0000,0000,0000,,Now the viability threshold is reached,
Dialogue: 0,0:14:57.00,0:15:01.49,Default,,0000,0000,0000,,and the frequency distribution\Nhas dramatically changed
Dialogue: 0,0:15:01.52,0:15:02.99,Default,,0000,0000,0000,,and, in fact, stabilizes.
Dialogue: 0,0:15:03.02,0:15:04.53,Default,,0000,0000,0000,,And now what I did there
Dialogue: 0,0:15:04.55,0:15:08.15,Default,,0000,0000,0000,,is, I was being nasty,\NI just turned up the heat again and again.
Dialogue: 0,0:15:08.17,0:15:10.52,Default,,0000,0000,0000,,And of course, it reaches\Nthe viability threshold.
Dialogue: 0,0:15:10.54,0:15:13.41,Default,,0000,0000,0000,,And I'm just showing this to you\Nagain because it's so nice.
Dialogue: 0,0:15:13.43,0:15:14.98,Default,,0000,0000,0000,,You hit the viability threshold.
Dialogue: 0,0:15:15.00,0:15:16.98,Default,,0000,0000,0000,,The distribution changes to "alive!"
Dialogue: 0,0:15:17.43,0:15:20.65,Default,,0000,0000,0000,,And then, once you hit the threshold
Dialogue: 0,0:15:20.67,0:15:24.72,Default,,0000,0000,0000,,where the mutation rate is so high\Nthat you cannot self-reproduce,
Dialogue: 0,0:15:24.74,0:15:29.67,Default,,0000,0000,0000,,you cannot copy the information\Nforward to your offspring
Dialogue: 0,0:15:29.69,0:15:34.42,Default,,0000,0000,0000,,without making so many mistakes\Nthat your ability to replicate vanishes.
Dialogue: 0,0:15:34.44,0:15:36.30,Default,,0000,0000,0000,,And then, that signature is lost.
Dialogue: 0,0:15:37.96,0:15:39.66,Default,,0000,0000,0000,,What do we learn from that?
Dialogue: 0,0:15:39.69,0:15:43.48,Default,,0000,0000,0000,,Well, I think we learn\Na number of things from that.
Dialogue: 0,0:15:43.51,0:15:44.98,Default,,0000,0000,0000,,One of them is,
Dialogue: 0,0:15:45.00,0:15:50.22,Default,,0000,0000,0000,,if we are able to think about life\Nin abstract terms --
Dialogue: 0,0:15:50.25,0:15:52.88,Default,,0000,0000,0000,,and we're not talking\Nabout things like plants,
Dialogue: 0,0:15:52.90,0:15:54.83,Default,,0000,0000,0000,,and we're not talking about amino acids,
Dialogue: 0,0:15:54.85,0:15:56.62,Default,,0000,0000,0000,,and we're not talking about bacteria,
Dialogue: 0,0:15:56.64,0:15:58.75,Default,,0000,0000,0000,,but we think in terms of processes --
Dialogue: 0,0:15:58.77,0:16:00.98,Default,,0000,0000,0000,,then we could start to think about life
Dialogue: 0,0:16:01.00,0:16:03.62,Default,,0000,0000,0000,,not as something\Nthat is so special to Earth,
Dialogue: 0,0:16:03.64,0:16:06.15,Default,,0000,0000,0000,,but that, in fact, could exist anywhere.
Dialogue: 0,0:16:06.18,0:16:10.49,Default,,0000,0000,0000,,Because it really only has to do\Nwith these concepts of information,
Dialogue: 0,0:16:10.51,0:16:14.57,Default,,0000,0000,0000,,of storing information\Nwithin physical substrates --
Dialogue: 0,0:16:14.60,0:16:18.61,Default,,0000,0000,0000,,anything: bits, nucleic acids,\Nanything that's an alphabet --
Dialogue: 0,0:16:18.64,0:16:20.52,Default,,0000,0000,0000,,and make sure that there's some process
Dialogue: 0,0:16:20.54,0:16:24.25,Default,,0000,0000,0000,,so that this information can be stored\Nfor much longer than you would expect --
Dialogue: 0,0:16:24.82,0:16:29.15,Default,,0000,0000,0000,,the time scales for\Nthe deterioration of information.
Dialogue: 0,0:16:29.18,0:16:32.34,Default,,0000,0000,0000,,And if you can do that,\Nthen you have life.
Dialogue: 0,0:16:32.37,0:16:34.62,Default,,0000,0000,0000,,So the first thing that we learn
Dialogue: 0,0:16:34.65,0:16:39.86,Default,,0000,0000,0000,,is that it is possible to define life\Nin terms of processes alone,
Dialogue: 0,0:16:39.88,0:16:44.86,Default,,0000,0000,0000,,without referring at all\Nto the type of things that we hold dear,
Dialogue: 0,0:16:44.88,0:16:47.55,Default,,0000,0000,0000,,as far as the type of life on Earth is.
Dialogue: 0,0:16:47.58,0:16:50.22,Default,,0000,0000,0000,,And that, in a sense, removes us again,
Dialogue: 0,0:16:50.24,0:16:53.07,Default,,0000,0000,0000,,like all of our scientific discoveries,\Nor many of them --
Dialogue: 0,0:16:53.10,0:16:55.87,Default,,0000,0000,0000,,it's this continuous dethroning of man --
Dialogue: 0,0:16:55.89,0:16:58.62,Default,,0000,0000,0000,,of how we think we're special\Nbecause we're alive.
Dialogue: 0,0:16:58.64,0:17:01.70,Default,,0000,0000,0000,,Well, we can make life;\Nwe can make life in the computer.
Dialogue: 0,0:17:01.72,0:17:03.54,Default,,0000,0000,0000,,Granted, it's limited,
Dialogue: 0,0:17:03.56,0:17:08.68,Default,,0000,0000,0000,,but we have learned what it takes\Nin order to actually construct it.
Dialogue: 0,0:17:08.71,0:17:11.49,Default,,0000,0000,0000,,And once we have that,
Dialogue: 0,0:17:11.52,0:17:14.16,Default,,0000,0000,0000,,then it is not such\Na difficult task anymore
Dialogue: 0,0:17:14.19,0:17:18.34,Default,,0000,0000,0000,,to say, if we understand\Nthe fundamental processes
Dialogue: 0,0:17:18.36,0:17:21.71,Default,,0000,0000,0000,,that do not refer\Nto any particular substrate,
Dialogue: 0,0:17:21.73,0:17:25.50,Default,,0000,0000,0000,,then we can go out and try other worlds,
Dialogue: 0,0:17:25.52,0:17:29.30,Default,,0000,0000,0000,,figure out what kind of chemical\Nalphabets might there be,
Dialogue: 0,0:17:30.03,0:17:34.76,Default,,0000,0000,0000,,figure enough about the normal chemistry,\Nthe geochemistry of the planet,
Dialogue: 0,0:17:34.78,0:17:38.56,Default,,0000,0000,0000,,so that we know what this distribution\Nwould look like in the absence of life,
Dialogue: 0,0:17:38.58,0:17:41.55,Default,,0000,0000,0000,,and then look for large\Ndeviations from this --
Dialogue: 0,0:17:41.58,0:17:46.69,Default,,0000,0000,0000,,this thing sticking out, which says,\N"This chemical really shouldn't be there."
Dialogue: 0,0:17:46.71,0:17:48.67,Default,,0000,0000,0000,,Now we don't know that there's life then,
Dialogue: 0,0:17:48.69,0:17:49.90,Default,,0000,0000,0000,,but we could say,
Dialogue: 0,0:17:49.92,0:17:53.69,Default,,0000,0000,0000,,"Well at least I'm going to have to take\Na look very precisely at this chemical
Dialogue: 0,0:17:53.71,0:17:55.76,Default,,0000,0000,0000,,and see where it comes from."
Dialogue: 0,0:17:55.78,0:17:59.49,Default,,0000,0000,0000,,And that might be our chance\Nof actually discovering life
Dialogue: 0,0:17:59.52,0:18:01.64,Default,,0000,0000,0000,,when we cannot visibly see it.
Dialogue: 0,0:18:01.66,0:18:06.22,Default,,0000,0000,0000,,And so that's really the only\Ntake-home message that I have for you.
Dialogue: 0,0:18:06.25,0:18:10.48,Default,,0000,0000,0000,,Life can be less mysterious\Nthan we make it out to be
Dialogue: 0,0:18:10.50,0:18:13.71,Default,,0000,0000,0000,,when we try to think\Nabout how it would be on other planets.
Dialogue: 0,0:18:14.28,0:18:17.67,Default,,0000,0000,0000,,And if we remove the mystery of life,
Dialogue: 0,0:18:17.69,0:18:22.38,Default,,0000,0000,0000,,then I think it is a little bit easier\Nfor us to think about how we live,
Dialogue: 0,0:18:22.40,0:18:25.46,Default,,0000,0000,0000,,and how perhaps we're not as special\Nas we always think we are.
Dialogue: 0,0:18:25.48,0:18:27.73,Default,,0000,0000,0000,,And I'm going to leave you with that.
Dialogue: 0,0:18:27.75,0:18:28.98,Default,,0000,0000,0000,,And thank you very much.
Dialogue: 0,0:18:29.00,0:18:31.17,Default,,0000,0000,0000,,(Applause)