[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:10.04,0:00:12.08,Default,,0000,0000,0000,,So, I have a strange career.
Dialogue: 0,0:00:12.80,0:00:15.92,Default,,0000,0000,0000,,I know it because people come up to me,\Nlike colleagues, and say,
Dialogue: 0,0:00:15.94,0:00:17.81,Default,,0000,0000,0000,,"Chris, you have a strange career."
Dialogue: 0,0:00:17.84,0:00:19.48,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:00:19.80,0:00:21.12,Default,,0000,0000,0000,,And I can see their point,
Dialogue: 0,0:00:21.14,0:00:26.48,Default,,0000,0000,0000,,because I started my career\Nas a theoretical nuclear physicist.
Dialogue: 0,0:00:26.50,0:00:30.66,Default,,0000,0000,0000,,And I was thinking about quarks\Nand gluons and heavy ion collisions,
Dialogue: 0,0:00:30.69,0:00:32.48,Default,,0000,0000,0000,,and I was only 14 years old...
Dialogue: 0,0:00:33.09,0:00:35.78,Default,,0000,0000,0000,,No, no, I wasn't 14 years old.
Dialogue: 0,0:00:36.74,0:00:38.48,Default,,0000,0000,0000,,But after that,
Dialogue: 0,0:00:39.30,0:00:41.24,Default,,0000,0000,0000,,I actually had my own lab
Dialogue: 0,0:00:41.26,0:00:43.38,Default,,0000,0000,0000,,in the Computational\NNeuroscience department,
Dialogue: 0,0:00:43.40,0:00:45.13,Default,,0000,0000,0000,,and I wasn't doing any neuroscience.
Dialogue: 0,0:00:45.15,0:00:48.08,Default,,0000,0000,0000,,Later, I would work\Non evolutionary genetics,
Dialogue: 0,0:00:48.11,0:00:50.06,Default,,0000,0000,0000,,and I would work on systems biology.
Dialogue: 0,0:00:50.08,0:00:52.75,Default,,0000,0000,0000,,But I'm going to tell you\Nabout something else today.
Dialogue: 0,0:00:52.77,0:00:57.03,Default,,0000,0000,0000,,I'm going to tell you\Nabout how I learned something about life.
Dialogue: 0,0:00:57.06,0:01:00.54,Default,,0000,0000,0000,,And I was actually a rocket scientist.
Dialogue: 0,0:01:00.56,0:01:02.86,Default,,0000,0000,0000,,I wasn't really a rocket scientist,
Dialogue: 0,0:01:02.89,0:01:07.24,Default,,0000,0000,0000,,but I was working\Nat the Jet Propulsion Laboratory
Dialogue: 0,0:01:07.77,0:01:10.40,Default,,0000,0000,0000,,in sunny California, where it's warm;
Dialogue: 0,0:01:10.43,0:01:14.28,Default,,0000,0000,0000,,whereas now I am\Nin the mid-West, and it's cold.
Dialogue: 0,0:01:14.30,0:01:16.98,Default,,0000,0000,0000,,But it was an exciting experience.
Dialogue: 0,0:01:17.00,0:01:20.44,Default,,0000,0000,0000,,One day, a NASA manager\Ncomes into my office,
Dialogue: 0,0:01:20.47,0:01:22.98,Default,,0000,0000,0000,,sits down and says
Dialogue: 0,0:01:23.72,0:01:25.47,Default,,0000,0000,0000,,that's my office, right there,
Dialogue: 0,0:01:25.49,0:01:28.92,Default,,0000,0000,0000,,and I had a nice office\Nwith the sun shining... anyway -
Dialogue: 0,0:01:30.33,0:01:31.40,Default,,0000,0000,0000,,He said, "Chris,
Dialogue: 0,0:01:32.10,0:01:35.90,Default,,0000,0000,0000,,can you please tell us,\Nhow do we look for life outside Earth?"
Dialogue: 0,0:01:36.86,0:01:39.44,Default,,0000,0000,0000,,And that came as a surprise to me,
Dialogue: 0,0:01:39.46,0:01:43.10,Default,,0000,0000,0000,,because I was actually hired\Nto work on quantum computation.
Dialogue: 0,0:01:43.61,0:01:45.11,Default,,0000,0000,0000,,Yet, I had a very good answer.
Dialogue: 0,0:01:45.14,0:01:46.56,Default,,0000,0000,0000,,I said, "I have no idea."
Dialogue: 0,0:01:46.94,0:01:48.09,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:01:48.11,0:01:53.46,Default,,0000,0000,0000,,And he told me, "Biosignatures,\Nwe need to look for a biosignature."
Dialogue: 0,0:01:53.48,0:01:54.84,Default,,0000,0000,0000,,And I said, "What is that?"
Dialogue: 0,0:01:54.87,0:01:57.46,Default,,0000,0000,0000,,And he said, "It's any\Nmeasurable phenomenon
Dialogue: 0,0:01:57.49,0:02:00.33,Default,,0000,0000,0000,,that allows us to indicate\Nthe presence of life."
Dialogue: 0,0:02:00.93,0:02:02.08,Default,,0000,0000,0000,,And I said, "Really?
Dialogue: 0,0:02:02.57,0:02:04.52,Default,,0000,0000,0000,,Because isn't that easy?
Dialogue: 0,0:02:04.54,0:02:06.38,Default,,0000,0000,0000,,I mean, we have life.
Dialogue: 0,0:02:08.20,0:02:10.17,Default,,0000,0000,0000,,Can't you apply a definition,
Dialogue: 0,0:02:10.20,0:02:14.37,Default,,0000,0000,0000,,for example, a Supreme Court-like\Ndefinition of life?"
Dialogue: 0,0:02:15.13,0:02:17.67,Default,,0000,0000,0000,,And then I thought about it\Na little bit, and I said,
Dialogue: 0,0:02:17.70,0:02:19.17,Default,,0000,0000,0000,,"Well, is it really that easy?
Dialogue: 0,0:02:19.20,0:02:21.39,Default,,0000,0000,0000,,Because, yes, if you see\Nsomething like this,
Dialogue: 0,0:02:21.41,0:02:23.76,Default,,0000,0000,0000,,then all right, fine,\NI'm going to call it life...
Dialogue: 0,0:02:23.78,0:02:24.93,Default,,0000,0000,0000,,No doubt about it.
Dialogue: 0,0:02:25.46,0:02:27.10,Default,,0000,0000,0000,,But here's something."
Dialogue: 0,0:02:27.12,0:02:30.18,Default,,0000,0000,0000,,And he goes, "Right,\Nthat's life too. I know that."
Dialogue: 0,0:02:30.20,0:02:34.79,Default,,0000,0000,0000,,Except, if you think that life\Nis also defined by things that die,
Dialogue: 0,0:02:34.82,0:02:36.57,Default,,0000,0000,0000,,you're not in luck with this thing,
Dialogue: 0,0:02:36.59,0:02:38.86,Default,,0000,0000,0000,,because that's actually\Na very strange organism.
Dialogue: 0,0:02:38.88,0:02:40.93,Default,,0000,0000,0000,,It grows up into the adult stage like that
Dialogue: 0,0:02:40.95,0:02:43.18,Default,,0000,0000,0000,,and then goes through\Na Benjamin Button phase,
Dialogue: 0,0:02:43.20,0:02:48.53,Default,,0000,0000,0000,,and actually goes backwards and backwards\Nuntil it's like a little embryo again,
Dialogue: 0,0:02:48.56,0:02:51.47,Default,,0000,0000,0000,,and then actually grows back up,\Nand back down and back up...
Dialogue: 0,0:02:51.50,0:02:53.28,Default,,0000,0000,0000,,Sort of yo-yo... and it never dies.
Dialogue: 0,0:02:53.30,0:02:56.22,Default,,0000,0000,0000,,So it's actually life,
Dialogue: 0,0:02:56.25,0:03:00.28,Default,,0000,0000,0000,,but it's actually not\Nas we thought life would be.
Dialogue: 0,0:03:00.79,0:03:02.70,Default,,0000,0000,0000,,And then you see something like that.
Dialogue: 0,0:03:02.73,0:03:05.60,Default,,0000,0000,0000,,And he was like, "My God,\Nwhat kind of a life form is that?"
Dialogue: 0,0:03:05.62,0:03:07.04,Default,,0000,0000,0000,,Anyone know?
Dialogue: 0,0:03:07.07,0:03:10.07,Default,,0000,0000,0000,,It's actually not life, it's a crystal.
Dialogue: 0,0:03:11.08,0:03:14.38,Default,,0000,0000,0000,,So once you start looking and looking\Nat smaller and smaller things...
Dialogue: 0,0:03:14.41,0:03:17.97,Default,,0000,0000,0000,,So this particular person wrote\Na whole article and said,
Dialogue: 0,0:03:17.99,0:03:19.77,Default,,0000,0000,0000,,"Hey, these are bacteria."
Dialogue: 0,0:03:19.80,0:03:22.17,Default,,0000,0000,0000,,Except, if you look a little bit closer,
Dialogue: 0,0:03:22.19,0:03:25.83,Default,,0000,0000,0000,,you see, in fact, that this thing\Nis way too small to be anything like that.
Dialogue: 0,0:03:25.85,0:03:29.01,Default,,0000,0000,0000,,So he was convinced,\Nbut, in fact, most people aren't.
Dialogue: 0,0:03:29.99,0:03:33.18,Default,,0000,0000,0000,,And then, of course,\NNASA also had a big announcement,
Dialogue: 0,0:03:33.20,0:03:36.06,Default,,0000,0000,0000,,and President Clinton\Ngave a press conference,
Dialogue: 0,0:03:36.09,0:03:41.84,Default,,0000,0000,0000,,about this amazing discovery\Nof life in a Martian meteorite.
Dialogue: 0,0:03:43.10,0:03:46.06,Default,,0000,0000,0000,,Except that nowadays,\Nit's heavily disputed.
Dialogue: 0,0:03:47.11,0:03:49.54,Default,,0000,0000,0000,,If you take the lesson\Nof all these pictures,
Dialogue: 0,0:03:49.56,0:03:52.46,Default,,0000,0000,0000,,then you realize, well, actually,\Nmaybe it's not that easy.
Dialogue: 0,0:03:52.48,0:03:55.88,Default,,0000,0000,0000,,Maybe I do need a definition of life
Dialogue: 0,0:03:55.91,0:03:58.18,Default,,0000,0000,0000,,in order to make that kind of distinction.
Dialogue: 0,0:03:59.01,0:04:01.54,Default,,0000,0000,0000,,So can life be defined?
Dialogue: 0,0:04:02.26,0:04:03.77,Default,,0000,0000,0000,,Well how would you go about it?
Dialogue: 0,0:04:03.79,0:04:07.80,Default,,0000,0000,0000,,Well of course, you'd go\Nto Encyclopedia Britannica and open at L.
Dialogue: 0,0:04:07.82,0:04:10.84,Default,,0000,0000,0000,,No, of course you don't do that;\Nyou put it somewhere in Google.
Dialogue: 0,0:04:10.86,0:04:12.45,Default,,0000,0000,0000,,And then you might get something.
Dialogue: 0,0:04:12.48,0:04:13.50,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:04:13.52,0:04:14.74,Default,,0000,0000,0000,,And what you might get...
Dialogue: 0,0:04:14.77,0:04:18.54,Default,,0000,0000,0000,,And anything that actually refers\Nto things that we are used to,
Dialogue: 0,0:04:18.57,0:04:19.79,Default,,0000,0000,0000,,you throw away.
Dialogue: 0,0:04:19.82,0:04:22.31,Default,,0000,0000,0000,,And then you might come up\Nwith something like this.
Dialogue: 0,0:04:22.34,0:04:24.06,Default,,0000,0000,0000,,And it says something longwinded
Dialogue: 0,0:04:25.82,0:04:28.82,Default,,0000,0000,0000,,complicated,\Nwith lots and lots of concepts.
Dialogue: 0,0:04:30.12,0:04:35.48,Default,,0000,0000,0000,,Who on Earth would write something\Nas convoluted and complex and inane?
Dialogue: 0,0:04:37.05,0:04:40.95,Default,,0000,0000,0000,,Oh, it's actually a really, really,\Nimportant set of concepts.
Dialogue: 0,0:04:40.98,0:04:43.08,Default,,0000,0000,0000,,So I'm highlighting just a few words
Dialogue: 0,0:04:43.10,0:04:47.52,Default,,0000,0000,0000,,and saying definitions\Nlike that rely on things
Dialogue: 0,0:04:47.55,0:04:53.70,Default,,0000,0000,0000,,that are not based on amino acids\Nor leaves or anything that we are used to,
Dialogue: 0,0:04:53.72,0:04:55.47,Default,,0000,0000,0000,,but in fact on processes only.
Dialogue: 0,0:04:55.50,0:04:57.37,Default,,0000,0000,0000,,And if you take a look at that,
Dialogue: 0,0:04:57.39,0:05:00.85,Default,,0000,0000,0000,,this was actually in a book that I wrote\Nthat deals with artificial life.
Dialogue: 0,0:05:00.87,0:05:05.10,Default,,0000,0000,0000,,And that explains why that NASA manager\Nwas actually in my office to begin with.
Dialogue: 0,0:05:05.12,0:05:08.21,Default,,0000,0000,0000,,Because the idea was that,\Nwith concepts like that,
Dialogue: 0,0:05:08.23,0:05:12.25,Default,,0000,0000,0000,,maybe we can actually\Nmanufacture a form of life.
Dialogue: 0,0:05:12.28,0:05:17.08,Default,,0000,0000,0000,,And so if you go and ask yourself,\N"What on Earth is artificial life?",
Dialogue: 0,0:05:17.10,0:05:20.77,Default,,0000,0000,0000,,let me give you a whirlwind tour\Nof how all this stuff came about.
Dialogue: 0,0:05:20.79,0:05:24.93,Default,,0000,0000,0000,,And it started out quite a while ago,
Dialogue: 0,0:05:24.95,0:05:29.28,Default,,0000,0000,0000,,when someone wrote one of the first\Nsuccessful computer viruses.
Dialogue: 0,0:05:29.58,0:05:31.76,Default,,0000,0000,0000,,And for those of you\Nwho aren't old enough,
Dialogue: 0,0:05:31.78,0:05:34.36,Default,,0000,0000,0000,,you have no idea\Nhow this infection was working...
Dialogue: 0,0:05:34.39,0:05:36.65,Default,,0000,0000,0000,,Namely, through these floppy disks.
Dialogue: 0,0:05:36.67,0:05:40.56,Default,,0000,0000,0000,,But the interesting thing\Nabout these computer virus infections
Dialogue: 0,0:05:40.58,0:05:44.73,Default,,0000,0000,0000,,was that, if you look at the rate\Nat which the infection worked,
Dialogue: 0,0:05:44.76,0:05:48.91,Default,,0000,0000,0000,,they show this spiky behavior\Nthat you're used to from a flu virus.
Dialogue: 0,0:05:48.93,0:05:51.28,Default,,0000,0000,0000,,And it is in fact due to this arms race
Dialogue: 0,0:05:51.30,0:05:54.76,Default,,0000,0000,0000,,between hackers\Nand operating system designers
Dialogue: 0,0:05:54.78,0:05:56.38,Default,,0000,0000,0000,,that things go back and forth.
Dialogue: 0,0:05:56.40,0:06:00.92,Default,,0000,0000,0000,,And the result is kind of\Na tree of life of these viruses,
Dialogue: 0,0:06:00.94,0:06:04.54,Default,,0000,0000,0000,,a phylogeny that looks very much\Nlike the type of life
Dialogue: 0,0:06:04.57,0:06:06.100,Default,,0000,0000,0000,,that we're used to,\Nat least on the viral level.
Dialogue: 0,0:06:07.02,0:06:08.35,Default,,0000,0000,0000,,So is that life?
Dialogue: 0,0:06:08.57,0:06:10.18,Default,,0000,0000,0000,,Not as far as I'm concerned.
Dialogue: 0,0:06:10.21,0:06:13.05,Default,,0000,0000,0000,,Why? Because these things\Ndon't evolve by themselves.
Dialogue: 0,0:06:13.07,0:06:15.02,Default,,0000,0000,0000,,In fact, they have hackers writing them.
Dialogue: 0,0:06:15.05,0:06:18.88,Default,,0000,0000,0000,,But the idea was taken\Nvery quickly a little bit further,
Dialogue: 0,0:06:18.90,0:06:22.70,Default,,0000,0000,0000,,when a scientist working\Nat the Santa Fe Institute decided,
Dialogue: 0,0:06:22.74,0:06:25.87,Default,,0000,0000,0000,,"Why don't we try to package\Nthese little viruses
Dialogue: 0,0:06:26.30,0:06:28.51,Default,,0000,0000,0000,,in artificial worlds\Ninside of the computer
Dialogue: 0,0:06:28.53,0:06:29.80,Default,,0000,0000,0000,,and let them evolve?"
Dialogue: 0,0:06:29.83,0:06:31.42,Default,,0000,0000,0000,,And this was Steen Rasmussen.
Dialogue: 0,0:06:31.45,0:06:34.14,Default,,0000,0000,0000,,And he designed this system,\Nbut it really didn't work,
Dialogue: 0,0:06:34.16,0:06:37.05,Default,,0000,0000,0000,,because his viruses\Nwere constantly destroying each other.
Dialogue: 0,0:06:37.07,0:06:41.59,Default,,0000,0000,0000,,But there was another scientist\Nwho had been watching this, an ecologist.
Dialogue: 0,0:06:41.61,0:06:44.10,Default,,0000,0000,0000,,And he went home and says,\N"I know how to fix this."
Dialogue: 0,0:06:44.13,0:06:45.77,Default,,0000,0000,0000,,And he wrote the Tierra system,
Dialogue: 0,0:06:45.80,0:06:47.00,Default,,0000,0000,0000,,and, in my book,
Dialogue: 0,0:06:47.02,0:06:51.25,Default,,0000,0000,0000,,is in fact one of the first\Ntruly artificial living systems...
Dialogue: 0,0:06:51.27,0:06:54.74,Default,,0000,0000,0000,,Except for the fact that these programs\Ndidn't really grow in complexity.
Dialogue: 0,0:06:54.76,0:06:57.62,Default,,0000,0000,0000,,So having seen this work,\Nworked a little bit on this,
Dialogue: 0,0:06:57.65,0:06:59.30,Default,,0000,0000,0000,,this is where I came in.
Dialogue: 0,0:06:59.33,0:07:02.97,Default,,0000,0000,0000,,And I decided to create a system\Nthat has all the properties
Dialogue: 0,0:07:02.100,0:07:06.84,Default,,0000,0000,0000,,that are necessary to see, in fact,\Nthe evolution of complexity,
Dialogue: 0,0:07:06.87,0:07:10.17,Default,,0000,0000,0000,,more and more complex\Nproblems constantly evolving.
Dialogue: 0,0:07:10.19,0:07:13.98,Default,,0000,0000,0000,,And of course, since I really don't know\Nhow to write code, I had help in this.
Dialogue: 0,0:07:14.00,0:07:15.55,Default,,0000,0000,0000,,I had two undergraduate students
Dialogue: 0,0:07:15.57,0:07:18.30,Default,,0000,0000,0000,,at California Institute of Technology\Nthat worked with me.
Dialogue: 0,0:07:19.22,0:07:22.08,Default,,0000,0000,0000,,That's Charles Ofria on the left,\NTitus Brown on the right.
Dialogue: 0,0:07:22.40,0:07:25.44,Default,,0000,0000,0000,,They are now, actually,\Nrespectable professors
Dialogue: 0,0:07:25.46,0:07:27.20,Default,,0000,0000,0000,,at Michigan State University,
Dialogue: 0,0:07:27.23,0:07:31.73,Default,,0000,0000,0000,,but I can assure you, back in the day,\Nwe were not a respectable team.
Dialogue: 0,0:07:31.75,0:07:33.80,Default,,0000,0000,0000,,And I'm really happy\Nthat no photo survives
Dialogue: 0,0:07:33.82,0:07:36.35,Default,,0000,0000,0000,,of the three of us\Nanywhere close together.
Dialogue: 0,0:07:37.09,0:07:38.97,Default,,0000,0000,0000,,But what is this system like?
Dialogue: 0,0:07:38.99,0:07:41.18,Default,,0000,0000,0000,,Well I can't really go into the details,
Dialogue: 0,0:07:41.20,0:07:43.86,Default,,0000,0000,0000,,but what you see here\Nis some of the entrails.
Dialogue: 0,0:07:43.88,0:07:47.97,Default,,0000,0000,0000,,But what I wanted to focus on\Nis this type of population structure.
Dialogue: 0,0:07:47.99,0:07:50.46,Default,,0000,0000,0000,,There's about 10,000\Nprograms sitting here.
Dialogue: 0,0:07:50.49,0:07:53.40,Default,,0000,0000,0000,,And all different strains\Nare colored in different colors.
Dialogue: 0,0:07:53.43,0:07:57.03,Default,,0000,0000,0000,,And as you see here, there are groups\Nthat are growing on top of each other,
Dialogue: 0,0:07:57.06,0:07:58.40,Default,,0000,0000,0000,,because they are spreading.
Dialogue: 0,0:07:58.42,0:08:02.53,Default,,0000,0000,0000,,Any time there is a program\Nthat's better at surviving in this world,
Dialogue: 0,0:08:02.55,0:08:04.52,Default,,0000,0000,0000,,due to whatever mutation it has acquired,
Dialogue: 0,0:08:04.54,0:08:08.01,Default,,0000,0000,0000,,it is going to spread over the others\Nand drive the others to extinction.
Dialogue: 0,0:08:08.04,0:08:09.59,Default,,0000,0000,0000,,So I'm going to show you a movie
Dialogue: 0,0:08:09.62,0:08:11.84,Default,,0000,0000,0000,,where you're going to see\Nthat kind of dynamic.
Dialogue: 0,0:08:11.87,0:08:16.14,Default,,0000,0000,0000,,And these kinds of experiments are started\Nwith programs that we wrote ourselves.
Dialogue: 0,0:08:16.17,0:08:19.50,Default,,0000,0000,0000,,We write our own stuff, replicate it,\Nand are very proud of ourselves.
Dialogue: 0,0:08:19.53,0:08:22.30,Default,,0000,0000,0000,,And we put them in,\Nand what you see immediately
Dialogue: 0,0:08:22.33,0:08:25.39,Default,,0000,0000,0000,,is that there are waves\Nand waves of innovation.
Dialogue: 0,0:08:25.42,0:08:27.31,Default,,0000,0000,0000,,By the way, this is highly accelerated,
Dialogue: 0,0:08:27.34,0:08:29.53,Default,,0000,0000,0000,,so it's like a 1000 generations a second.
Dialogue: 0,0:08:29.56,0:08:34.12,Default,,0000,0000,0000,,But immediately, the system goes like,\N"What kind of dumb piece of code was this?
Dialogue: 0,0:08:34.15,0:08:37.87,Default,,0000,0000,0000,,This can be improved upon\Nin so many ways, so quickly."
Dialogue: 0,0:08:37.89,0:08:41.64,Default,,0000,0000,0000,,So you see waves of new types\Ntaking over the other types.
Dialogue: 0,0:08:41.66,0:08:44.23,Default,,0000,0000,0000,,And this type of activity\Ngoes on for quite a while,
Dialogue: 0,0:08:44.25,0:08:49.38,Default,,0000,0000,0000,,until the main easy things\Nhave been acquired by these programs.
Dialogue: 0,0:08:49.60,0:08:53.46,Default,,0000,0000,0000,,And then, you see\Nsort of like a stasis coming on
Dialogue: 0,0:08:53.70,0:08:56.24,Default,,0000,0000,0000,,where the system essentially waits
Dialogue: 0,0:08:56.30,0:08:59.48,Default,,0000,0000,0000,,for a new type of innovation,\Nlike this one,
Dialogue: 0,0:08:59.51,0:09:03.79,Default,,0000,0000,0000,,which is going to spread over\Nall the other innovations that were before
Dialogue: 0,0:09:03.81,0:09:06.78,Default,,0000,0000,0000,,and is erasing the genes\Nthat it had before,
Dialogue: 0,0:09:06.80,0:09:10.78,Default,,0000,0000,0000,,until a new type of higher level\Nof complexity has been achieved.
Dialogue: 0,0:09:10.80,0:09:13.78,Default,,0000,0000,0000,,And this process goes on and on and on.
Dialogue: 0,0:09:14.47,0:09:15.78,Default,,0000,0000,0000,,So what we see here
Dialogue: 0,0:09:15.81,0:09:19.97,Default,,0000,0000,0000,,is a system that lives in very much\Nthe way we're used to how life goes.
Dialogue: 0,0:09:20.69,0:09:24.81,Default,,0000,0000,0000,,But what the NASA people\Nhad asked me really was,
Dialogue: 0,0:09:25.21,0:09:27.98,Default,,0000,0000,0000,,"Do these guys have a biosignature?
Dialogue: 0,0:09:28.58,0:09:30.39,Default,,0000,0000,0000,,Can we measure this type of life?
Dialogue: 0,0:09:30.42,0:09:31.61,Default,,0000,0000,0000,,Because if we can,
Dialogue: 0,0:09:31.63,0:09:35.48,Default,,0000,0000,0000,,maybe we have a chance of actually\Ndiscovering life somewhere else
Dialogue: 0,0:09:35.51,0:09:38.66,Default,,0000,0000,0000,,without being biased\Nby things like amino acids."
Dialogue: 0,0:09:39.22,0:09:40.64,Default,,0000,0000,0000,,So I sat down a little bit,
Dialogue: 0,0:09:40.73,0:09:43.02,Default,,0000,0000,0000,,and I said, "Well, if we do this,
Dialogue: 0,0:09:43.06,0:09:46.41,Default,,0000,0000,0000,,perhaps we should construct a biosignature
Dialogue: 0,0:09:46.68,0:09:51.65,Default,,0000,0000,0000,,that is based on life\Nas a universal process.
Dialogue: 0,0:09:52.00,0:09:56.96,Default,,0000,0000,0000,,In fact, it should perhaps make use\Nof the concepts that I developed
Dialogue: 0,0:09:56.99,0:10:01.08,Default,,0000,0000,0000,,just in order to sort of capture\Nwhat a simple living system might be."
Dialogue: 0,0:10:01.80,0:10:03.32,Default,,0000,0000,0000,,And the thing I came up with...
Dialogue: 0,0:10:03.34,0:10:07.32,Default,,0000,0000,0000,,I have to first give you\Nan introduction about the idea,
Dialogue: 0,0:10:07.35,0:10:10.89,Default,,0000,0000,0000,,and maybe that would be\Na meaning detector,
Dialogue: 0,0:10:10.91,0:10:12.46,Default,,0000,0000,0000,,rather than a life detector.
Dialogue: 0,0:10:13.03,0:10:14.78,Default,,0000,0000,0000,,And the way we would do that...
Dialogue: 0,0:10:14.80,0:10:17.44,Default,,0000,0000,0000,,I would like to find out\Nhow I can distinguish text
Dialogue: 0,0:10:17.46,0:10:22.11,Default,,0000,0000,0000,,that was written by a million monkeys,\Nas opposed to text that is in our books.
Dialogue: 0,0:10:23.34,0:10:25.22,Default,,0000,0000,0000,,And I would like to do it in such a way
Dialogue: 0,0:10:25.25,0:10:28.12,Default,,0000,0000,0000,,that I don't actually have to be able\Nto read the language,
Dialogue: 0,0:10:28.15,0:10:29.92,Default,,0000,0000,0000,,because I'm sure I won't be able to.
Dialogue: 0,0:10:29.94,0:10:32.44,Default,,0000,0000,0000,,As long as I know\Nthat there's some sort of alphabet.
Dialogue: 0,0:10:32.47,0:10:35.30,Default,,0000,0000,0000,,So here would be a frequency plot
Dialogue: 0,0:10:35.32,0:10:39.00,Default,,0000,0000,0000,,of how often you find\Neach of the 26 letters of the alphabet
Dialogue: 0,0:10:39.03,0:10:41.24,Default,,0000,0000,0000,,in a text written by random monkeys.
Dialogue: 0,0:10:43.10,0:10:47.65,Default,,0000,0000,0000,,And obviously, each of these letters\Ncomes off about roughly equally frequent.
Dialogue: 0,0:10:47.67,0:10:51.26,Default,,0000,0000,0000,,But if you now look at the same\Ndistribution in English texts,
Dialogue: 0,0:10:52.09,0:10:53.34,Default,,0000,0000,0000,,it looks like that.
Dialogue: 0,0:10:53.90,0:10:57.45,Default,,0000,0000,0000,,And I'm telling you,\Nthis is very robust across English texts.
Dialogue: 0,0:10:57.47,0:11:00.46,Default,,0000,0000,0000,,And if I look at French texts,\Nit looks a little bit different,
Dialogue: 0,0:11:00.48,0:11:01.66,Default,,0000,0000,0000,,or Italian or German.
Dialogue: 0,0:11:01.68,0:11:05.10,Default,,0000,0000,0000,,They all have their own type\Nof frequency distribution,
Dialogue: 0,0:11:05.12,0:11:06.56,Default,,0000,0000,0000,,but it's robust.
Dialogue: 0,0:11:06.58,0:11:09.79,Default,,0000,0000,0000,,It doesn't matter whether it writes\Nabout politics or about science.
Dialogue: 0,0:11:09.81,0:11:15.59,Default,,0000,0000,0000,,It doesn't matter whether it's a poem\Nor whether it's a mathematical text.
Dialogue: 0,0:11:15.62,0:11:17.45,Default,,0000,0000,0000,,It's a robust signature,
Dialogue: 0,0:11:17.48,0:11:19.30,Default,,0000,0000,0000,,and it's very stable.
Dialogue: 0,0:11:19.32,0:11:21.48,Default,,0000,0000,0000,,As long as our books\Nare written in English...
Dialogue: 0,0:11:21.50,0:11:24.29,Default,,0000,0000,0000,,Because people are rewriting them\Nand recopying them...
Dialogue: 0,0:11:24.32,0:11:25.68,Default,,0000,0000,0000,,It's going to be there.
Dialogue: 0,0:11:25.70,0:11:31.76,Default,,0000,0000,0000,,So that inspired me to think about,\Nwell, what if I try to use this idea
Dialogue: 0,0:11:31.78,0:11:35.54,Default,,0000,0000,0000,,in order, not to detect random texts\Nfrom texts with meaning,
Dialogue: 0,0:11:35.56,0:11:39.29,Default,,0000,0000,0000,,but rather detect the fact\Nthat there is meaning
Dialogue: 0,0:11:39.32,0:11:41.84,Default,,0000,0000,0000,,in the biomolecules that make up life.
Dialogue: 0,0:11:41.87,0:11:43.04,Default,,0000,0000,0000,,But first I have to ask:
Dialogue: 0,0:11:43.06,0:11:44.55,Default,,0000,0000,0000,,what are these building blocks,
Dialogue: 0,0:11:44.57,0:11:47.58,Default,,0000,0000,0000,,like the alphabet, elements\Nthat I showed you?
Dialogue: 0,0:11:47.69,0:11:50.56,Default,,0000,0000,0000,,Well it turns out, we have\Nmany different alternatives
Dialogue: 0,0:11:51.19,0:11:53.50,Default,,0000,0000,0000,,for such a set of building blocks.
Dialogue: 0,0:11:53.53,0:11:54.78,Default,,0000,0000,0000,,We could use amino acids,
Dialogue: 0,0:11:54.80,0:11:58.00,Default,,0000,0000,0000,,we could use nucleic acids,\Ncarboxylic acids, fatty acids.
Dialogue: 0,0:11:58.02,0:12:01.46,Default,,0000,0000,0000,,In fact, chemistry's extremely rich,\Nand our body uses a lot of them.
Dialogue: 0,0:12:01.49,0:12:03.79,Default,,0000,0000,0000,,So that we actually, to test this idea,
Dialogue: 0,0:12:03.82,0:12:07.36,Default,,0000,0000,0000,,first took a look at amino acids\Nand some other carboxylic acids.
Dialogue: 0,0:12:07.39,0:12:08.86,Default,,0000,0000,0000,,And here's the result.
Dialogue: 0,0:12:10.28,0:12:13.45,Default,,0000,0000,0000,,Here is, in fact, what you get
Dialogue: 0,0:12:13.47,0:12:16.50,Default,,0000,0000,0000,,if you, for example, look\Nat the distribution of amino acids
Dialogue: 0,0:12:16.52,0:12:21.26,Default,,0000,0000,0000,,on a comet or in interstellar space\Nor, in fact, in a laboratory,
Dialogue: 0,0:12:21.28,0:12:24.54,Default,,0000,0000,0000,,where you made very sure\Nthat in your primordial soup,
Dialogue: 0,0:12:24.56,0:12:26.48,Default,,0000,0000,0000,,there is no living stuff in there.
Dialogue: 0,0:12:27.60,0:12:32.57,Default,,0000,0000,0000,,What you find is mostly\Nglycine and then alanine
Dialogue: 0,0:12:32.61,0:12:34.97,Default,,0000,0000,0000,,and there's some trace elements\Nof the other ones.
Dialogue: 0,0:12:34.99,0:12:37.42,Default,,0000,0000,0000,,That is also very robust...
Dialogue: 0,0:12:37.64,0:12:41.48,Default,,0000,0000,0000,,What you find in systems like Earth
Dialogue: 0,0:12:41.50,0:12:44.64,Default,,0000,0000,0000,,where there are amino acids,\Nbut there is no life.
Dialogue: 0,0:12:44.67,0:12:49.30,Default,,0000,0000,0000,,But suppose you take some dirt\Nand dig through it
Dialogue: 0,0:12:49.32,0:12:52.28,Default,,0000,0000,0000,,and then put it into these spectrometers,
Dialogue: 0,0:12:52.31,0:12:54.40,Default,,0000,0000,0000,,because there's bacteria\Nall over the place;
Dialogue: 0,0:12:54.43,0:12:56.66,Default,,0000,0000,0000,,or you take water anywhere on Earth,
Dialogue: 0,0:12:56.68,0:12:58.20,Default,,0000,0000,0000,,because it's teaming with life,
Dialogue: 0,0:12:58.22,0:12:59.97,Default,,0000,0000,0000,,and you make the same analysis;
Dialogue: 0,0:12:59.100,0:13:02.58,Default,,0000,0000,0000,,the spectrum looks completely different.
Dialogue: 0,0:13:02.60,0:13:05.97,Default,,0000,0000,0000,,Of course, there is still\Nglycine and alanine,
Dialogue: 0,0:13:05.100,0:13:09.32,Default,,0000,0000,0000,,but in fact, there are these heavy\Nelements, these heavy amino acids,
Dialogue: 0,0:13:09.34,0:13:12.74,Default,,0000,0000,0000,,that are being produced\Nbecause they are valuable to the organism.
Dialogue: 0,0:13:13.87,0:13:17.80,Default,,0000,0000,0000,,And some other ones\Nthat are not used in the set of 20,
Dialogue: 0,0:13:17.83,0:13:21.24,Default,,0000,0000,0000,,they will not appear at all\Nin any type of concentration.
Dialogue: 0,0:13:21.55,0:13:24.26,Default,,0000,0000,0000,,So this also turns out\Nto be extremely robust.
Dialogue: 0,0:13:24.28,0:13:27.40,Default,,0000,0000,0000,,It doesn't matter what kind of sediment\Nyou're using to grind up,
Dialogue: 0,0:13:27.42,0:13:30.70,Default,,0000,0000,0000,,whether it's bacteria\Nor any other plants or animals.
Dialogue: 0,0:13:30.72,0:13:32.15,Default,,0000,0000,0000,,Anywhere there's life,
Dialogue: 0,0:13:32.17,0:13:34.12,Default,,0000,0000,0000,,you're going to have this distribution,
Dialogue: 0,0:13:34.15,0:13:35.96,Default,,0000,0000,0000,,as opposed to that distribution.
Dialogue: 0,0:13:35.99,0:13:39.23,Default,,0000,0000,0000,,And it is detectable\Nnot just in amino acids.
Dialogue: 0,0:13:40.05,0:13:41.27,Default,,0000,0000,0000,,Now you could ask:
Dialogue: 0,0:13:41.29,0:13:44.45,Default,,0000,0000,0000,,Well, what about these Avidians?
Dialogue: 0,0:13:44.47,0:13:47.52,Default,,0000,0000,0000,,The Avidians being the denizens\Nof this computer world
Dialogue: 0,0:13:47.55,0:13:50.99,Default,,0000,0000,0000,,where they are perfectly happy\Nreplicating and growing in complexity.
Dialogue: 0,0:13:51.02,0:13:56.04,Default,,0000,0000,0000,,So this is the distribution that you get\Nif, in fact, there is no life.
Dialogue: 0,0:13:56.06,0:13:58.78,Default,,0000,0000,0000,,They have about 28 of these instructions.
Dialogue: 0,0:13:58.80,0:14:02.15,Default,,0000,0000,0000,,And if you have a system where\Nthey're being replaced one by the other,
Dialogue: 0,0:14:02.18,0:14:04.36,Default,,0000,0000,0000,,it's like the monkeys\Nwriting on a typewriter.
Dialogue: 0,0:14:04.39,0:14:08.61,Default,,0000,0000,0000,,Each of these instructions\Nappears with roughly the equal frequency.
Dialogue: 0,0:14:09.52,0:14:14.30,Default,,0000,0000,0000,,But if you now take\Na set of replicating guys
Dialogue: 0,0:14:14.32,0:14:16.27,Default,,0000,0000,0000,,like in the video that you saw,
Dialogue: 0,0:14:16.29,0:14:17.81,Default,,0000,0000,0000,,it looks like this.
Dialogue: 0,0:14:18.60,0:14:20.07,Default,,0000,0000,0000,,So there are some instructions
Dialogue: 0,0:14:20.10,0:14:22.53,Default,,0000,0000,0000,,that are extremely valuable\Nto these organisms,
Dialogue: 0,0:14:22.55,0:14:24.52,Default,,0000,0000,0000,,and their frequency is going to be high.
Dialogue: 0,0:14:24.55,0:14:28.59,Default,,0000,0000,0000,,And there's actually some instructions\Nthat you only use once, if ever.
Dialogue: 0,0:14:28.61,0:14:30.14,Default,,0000,0000,0000,,So they are either poisonous
Dialogue: 0,0:14:30.16,0:14:34.66,Default,,0000,0000,0000,,or really should be used\Nat less of a level than random.
Dialogue: 0,0:14:34.69,0:14:37.38,Default,,0000,0000,0000,,In this case, the frequency is lower.
Dialogue: 0,0:14:38.33,0:14:41.00,Default,,0000,0000,0000,,And so now we can see,\Nis that really a robust signature?
Dialogue: 0,0:14:41.03,0:14:42.38,Default,,0000,0000,0000,,I can tell you indeed it is,
Dialogue: 0,0:14:42.41,0:14:45.66,Default,,0000,0000,0000,,because this type of spectrum,\Njust like what you've seen in books,
Dialogue: 0,0:14:45.68,0:14:47.83,Default,,0000,0000,0000,,and just like what you've seen\Nin amino acids,
Dialogue: 0,0:14:47.86,0:14:50.50,Default,,0000,0000,0000,,it doesn't really matter\Nhow you change the environment,
Dialogue: 0,0:14:50.52,0:14:53.15,Default,,0000,0000,0000,,it's very robust, it's going\Nto reflect the environment.
Dialogue: 0,0:14:53.17,0:14:56.12,Default,,0000,0000,0000,,So I'm going to show you now\Na little experiment that we did.
Dialogue: 0,0:14:56.14,0:14:57.53,Default,,0000,0000,0000,,And I have to explain to you,
Dialogue: 0,0:14:57.55,0:14:58.73,Default,,0000,0000,0000,,the top of this graph
Dialogue: 0,0:14:58.76,0:15:01.50,Default,,0000,0000,0000,,shows you that frequency\Ndistribution that I talked about.
Dialogue: 0,0:15:02.43,0:15:07.07,Default,,0000,0000,0000,,Here, that's the lifeless environment
Dialogue: 0,0:15:07.46,0:15:10.87,Default,,0000,0000,0000,,where each instruction occurs\Nat an equal frequency.
Dialogue: 0,0:15:11.80,0:15:16.80,Default,,0000,0000,0000,,And below there, I show, in fact,\Nthe mutation rate in the environment.
Dialogue: 0,0:15:16.82,0:15:20.12,Default,,0000,0000,0000,,And I'm starting this\Nat a mutation rate that is so high
Dialogue: 0,0:15:20.15,0:15:24.11,Default,,0000,0000,0000,,that even if you would drop\Na replicating program
Dialogue: 0,0:15:24.14,0:15:28.26,Default,,0000,0000,0000,,that would otherwise happily grow up\Nto fill the entire world,
Dialogue: 0,0:15:28.29,0:15:31.30,Default,,0000,0000,0000,,if you drop it in, it gets mutated\Nto death immediately.
Dialogue: 0,0:15:31.32,0:15:36.67,Default,,0000,0000,0000,,So there is no life possible\Nat that type of mutation rate.
Dialogue: 0,0:15:36.69,0:15:40.73,Default,,0000,0000,0000,,But then I'm going to slowly\Nturn down the heat, so to speak,
Dialogue: 0,0:15:40.75,0:15:42.94,Default,,0000,0000,0000,,and then there's this viability threshold
Dialogue: 0,0:15:42.96,0:15:46.85,Default,,0000,0000,0000,,where now it would be possible\Nfor a replicator to actually live.
Dialogue: 0,0:15:46.88,0:15:52.22,Default,,0000,0000,0000,,And indeed, we're going to be dropping\Nthese guys into that soup all the time.
Dialogue: 0,0:15:52.66,0:15:54.30,Default,,0000,0000,0000,,So let's see what that looks like.
Dialogue: 0,0:15:54.32,0:15:57.32,Default,,0000,0000,0000,,So first, nothing, nothing, nothing.
Dialogue: 0,0:15:57.34,0:15:59.16,Default,,0000,0000,0000,,Too hot, too hot.
Dialogue: 0,0:15:59.18,0:16:01.48,Default,,0000,0000,0000,,Now the viability threshold is reached,
Dialogue: 0,0:16:01.50,0:16:05.99,Default,,0000,0000,0000,,and the frequency distribution\Nhas dramatically changed
Dialogue: 0,0:16:06.02,0:16:07.49,Default,,0000,0000,0000,,and, in fact, stabilizes.
Dialogue: 0,0:16:07.52,0:16:09.03,Default,,0000,0000,0000,,And now what I did there
Dialogue: 0,0:16:09.05,0:16:12.65,Default,,0000,0000,0000,,is, I was being nasty,\NI just turned up the heat again and again.
Dialogue: 0,0:16:12.67,0:16:15.02,Default,,0000,0000,0000,,And of course, it reaches\Nthe viability threshold.
Dialogue: 0,0:16:15.04,0:16:17.91,Default,,0000,0000,0000,,And I'm just showing this to you\Nagain because it's so nice.
Dialogue: 0,0:16:17.93,0:16:19.48,Default,,0000,0000,0000,,You hit the viability threshold.
Dialogue: 0,0:16:19.50,0:16:22.02,Default,,0000,0000,0000,,The distribution changes to "alive!"
Dialogue: 0,0:16:22.43,0:16:25.65,Default,,0000,0000,0000,,And then, once you hit the threshold
Dialogue: 0,0:16:25.67,0:16:29.72,Default,,0000,0000,0000,,where the mutation rate is so high\Nthat you cannot self-reproduce,
Dialogue: 0,0:16:29.74,0:16:35.76,Default,,0000,0000,0000,,you cannot copy the information\Nforward to your offspring
Dialogue: 0,0:16:35.79,0:16:40.52,Default,,0000,0000,0000,,without making so many mistakes\Nthat your ability to replicate vanishes.
Dialogue: 0,0:16:40.54,0:16:42.40,Default,,0000,0000,0000,,And then, that signature is lost.
Dialogue: 0,0:16:44.16,0:16:45.86,Default,,0000,0000,0000,,What do we learn from that?
Dialogue: 0,0:16:46.19,0:16:49.98,Default,,0000,0000,0000,,Well, I think we learn\Na number of things from that.
Dialogue: 0,0:16:50.01,0:16:51.48,Default,,0000,0000,0000,,One of them is,
Dialogue: 0,0:16:51.50,0:16:56.72,Default,,0000,0000,0000,,if we are able to think about life\Nin abstract terms...
Dialogue: 0,0:16:56.75,0:16:59.38,Default,,0000,0000,0000,,And we're not talking\Nabout things like plants,
Dialogue: 0,0:16:59.40,0:17:01.33,Default,,0000,0000,0000,,and we're not talking about amino acids,
Dialogue: 0,0:17:01.35,0:17:03.12,Default,,0000,0000,0000,,and we're not talking about bacteria,
Dialogue: 0,0:17:03.14,0:17:05.25,Default,,0000,0000,0000,,but we think in terms of processes...
Dialogue: 0,0:17:05.27,0:17:07.48,Default,,0000,0000,0000,,Then we could start to think about life
Dialogue: 0,0:17:07.50,0:17:10.12,Default,,0000,0000,0000,,not as something\Nthat is so special to Earth,
Dialogue: 0,0:17:10.14,0:17:12.65,Default,,0000,0000,0000,,but that, in fact, could exist anywhere.
Dialogue: 0,0:17:12.68,0:17:16.99,Default,,0000,0000,0000,,Because it really only has to do\Nwith these concepts of information,
Dialogue: 0,0:17:17.01,0:17:21.07,Default,,0000,0000,0000,,of storing information\Nwithin physical substrates...
Dialogue: 0,0:17:21.10,0:17:25.11,Default,,0000,0000,0000,,Anything: bits, nucleic acids,\Nanything that's an alphabet...
Dialogue: 0,0:17:25.14,0:17:27.02,Default,,0000,0000,0000,,And make sure that there's some process
Dialogue: 0,0:17:27.04,0:17:30.75,Default,,0000,0000,0000,,so that this information can be stored\Nfor much longer than you would expect...
Dialogue: 0,0:17:31.32,0:17:35.65,Default,,0000,0000,0000,,The time scales for\Nthe deterioration of information.
Dialogue: 0,0:17:35.68,0:17:38.84,Default,,0000,0000,0000,,And if you can do that,\Nthen you have life.
Dialogue: 0,0:17:38.87,0:17:41.12,Default,,0000,0000,0000,,So the first thing that we learn
Dialogue: 0,0:17:41.15,0:17:46.36,Default,,0000,0000,0000,,is that it is possible to define life\Nin terms of processes alone,
Dialogue: 0,0:17:46.38,0:17:51.36,Default,,0000,0000,0000,,without referring at all\Nto the type of things that we hold dear,
Dialogue: 0,0:17:51.38,0:17:54.05,Default,,0000,0000,0000,,as far as the type of life on Earth is.
Dialogue: 0,0:17:54.08,0:17:56.72,Default,,0000,0000,0000,,And that, in a sense, removes us again,
Dialogue: 0,0:17:56.74,0:17:59.57,Default,,0000,0000,0000,,like all of our scientific discoveries,\Nor many of them...
Dialogue: 0,0:17:59.60,0:18:02.37,Default,,0000,0000,0000,,It leads to s continuous\Ndethroning of man...
Dialogue: 0,0:18:02.39,0:18:05.12,Default,,0000,0000,0000,,Of how we think we're special\Nbecause we're alive.
Dialogue: 0,0:18:05.14,0:18:08.20,Default,,0000,0000,0000,,Well, we can make life;\Nwe can make life in the computer.
Dialogue: 0,0:18:08.22,0:18:10.54,Default,,0000,0000,0000,,Granted, it's limited,
Dialogue: 0,0:18:10.56,0:18:15.68,Default,,0000,0000,0000,,but we have learned what it takes\Nin order to actually construct it.
Dialogue: 0,0:18:15.71,0:18:18.49,Default,,0000,0000,0000,,And once we have that,
Dialogue: 0,0:18:18.52,0:18:21.16,Default,,0000,0000,0000,,then it is not such\Na difficult task anymore
Dialogue: 0,0:18:21.19,0:18:25.34,Default,,0000,0000,0000,,to say, if we understand\Nthe fundamental processes
Dialogue: 0,0:18:25.36,0:18:28.71,Default,,0000,0000,0000,,that do not refer\Nto any particular substrate,
Dialogue: 0,0:18:28.73,0:18:32.50,Default,,0000,0000,0000,,then we can go out and try other worlds,
Dialogue: 0,0:18:32.52,0:18:36.30,Default,,0000,0000,0000,,figure out what kind of chemical\Nalphabets might there be,
Dialogue: 0,0:18:37.03,0:18:41.76,Default,,0000,0000,0000,,figure enough about the normal chemistry,\Nthe geochemistry of the planet,
Dialogue: 0,0:18:41.78,0:18:45.56,Default,,0000,0000,0000,,so that we know what this distribution\Nwould look like in the absence of life,
Dialogue: 0,0:18:45.58,0:18:48.55,Default,,0000,0000,0000,,and then look for large\Ndeviations from this...
Dialogue: 0,0:18:48.58,0:18:53.69,Default,,0000,0000,0000,,This thing sticking out, which says,\N"This chemical really shouldn't be there."
Dialogue: 0,0:18:53.71,0:18:55.67,Default,,0000,0000,0000,,Now we don't know that there's life then,
Dialogue: 0,0:18:55.69,0:18:56.90,Default,,0000,0000,0000,,but we could say,
Dialogue: 0,0:18:56.92,0:19:00.69,Default,,0000,0000,0000,,"Well at least I'm going to have to take\Na look very precisely at this chemical
Dialogue: 0,0:19:00.71,0:19:02.76,Default,,0000,0000,0000,,and see where it comes from."
Dialogue: 0,0:19:02.78,0:19:06.49,Default,,0000,0000,0000,,And that might be our chance\Nof actually discovering life
Dialogue: 0,0:19:06.52,0:19:08.64,Default,,0000,0000,0000,,when we cannot visibly see it,
Dialogue: 0,0:19:09.27,0:19:10.87,Default,,0000,0000,0000,,as I've shown you.
Dialogue: 0,0:19:11.86,0:19:16.42,Default,,0000,0000,0000,,And so that's really the only\Ntake-home message that I have for you.
Dialogue: 0,0:19:16.45,0:19:20.68,Default,,0000,0000,0000,,Life can be less mysterious\Nthan we make it out to be
Dialogue: 0,0:19:20.70,0:19:23.91,Default,,0000,0000,0000,,when we try to think\Nabout how it would be on other planets.
Dialogue: 0,0:19:24.48,0:19:27.87,Default,,0000,0000,0000,,And if we remove the mystery of life,
Dialogue: 0,0:19:27.89,0:19:32.58,Default,,0000,0000,0000,,then I think it is a little bit easier\Nfor us to think about how we live,
Dialogue: 0,0:19:32.60,0:19:35.66,Default,,0000,0000,0000,,and how perhaps we're not as special\Nas we always think we are.
Dialogue: 0,0:19:36.08,0:19:38.33,Default,,0000,0000,0000,,And I'm going to leave you with that.
Dialogue: 0,0:19:38.35,0:19:39.58,Default,,0000,0000,0000,,And thank you very much.
Dialogue: 0,0:19:39.60,0:19:41.77,Default,,0000,0000,0000,,(Applause)