Finding life we can't imagine | Christoph Adami

Prevodilac: Aleksandar Petrović Lektor: Marija Stepanovic

So, I have a strange career.

Ja se bavim čudnim poslom.

I know it because people come up to me, like colleagues, and say,

Znam to zato što mi ljudi, kolege na primer, prilaze

"Chris, you have a strange career."

i kažu: "Krise, baviš se čudnim poslom."

(Laughter)

(Smeh)

And I can see their point,

Razumem šta hoće da kažu,

because I started my career as a theoretical nuclear physicist.

jer sam počeo karijeru

kao teoretičar nuklearne fizike.

And I was thinking about quarks and gluons and heavy ion collisions,

Razmišljao sam o kvarkovima i gluonima

i sudarima teških jona,

and I was only 14 years old --

a imao sam samo 14 godina.

No, no, I wasn't 14 years old.

Ne, nisam imao 14 godina.

But after that,

Ali posle toga

I actually had my own lab

sam zapravo imao svoju laboratoriju

in the Computational Neuroscience department,

na departmanu za računarske neuronauke

and I wasn't doing any neuroscience.

a uopšte se nisam bavio neuronaukama.

Later, I would work on evolutionary genetics,

Kasnije sam se bavio evolucionom genetikom,

and I would work on systems biology.

a potom biologijom sistema.

But I'm going to tell you about something else today.

Ali danas ću vam govoriti o nečemu drugom.

I'm going to tell you about how I learned something about life.

Govoriću vam

o tome kako sam naučio nešto o životu.

And I was actually a rocket scientist.

A bio sam raketni naučnik.

I wasn't really a rocket scientist,

Nisam baš bio raketni naučnik,

but I was working at the Jet Propulsion Laboratory

ali sam radio

u Laboratoriji za razvijanje mlaznog pogona

in sunny California, where it's warm;

u sunčanoj Kaliforniji, gde je toplo;

whereas now I am in the mid-West, and it's cold.

dok sada radim na srednjem Zapadu,

i hladno mi je.

But it was an exciting experience.

Ali bilo je to jedno uzbudljivo iskustvo.

One day, a NASA manager comes into my office,

Jednog dana službenik NASA-e je ušao u moju kancelariju,

sits down and says,

seo i rekao:

"Can you please tell us, how do we look for life outside Earth?"

"Možete li, molim vas, da nam kažete

kako da tražimo život van Zemlje?"

And that came as a surprise to me,

To me je iznenadilo

because I was actually hired to work on quantum computation.

jer sam bio zaposlen tamo

kako bih radio na kvantnom računarstvu.

Yet, I had a very good answer.

Ipak, imao sam veoma dobar odgovor na njegovo pitanje.

I said, "I have no idea."

(Laughter)

Rekao sam: "Nemam pojma."

And he told me, "Biosignatures, we need to look for a biosignature."

On mi je rekao: "Znakovi života,

treba da tragamo za znakovima života."

And I said, "What is that?"

Ja sam pitao: "Šta je to?"

And he said, "It's any measurable phenomenon

A on je rekao: "To su merljive pojave

that allows us to indicate the presence of life."

koje nam ukazuju na prisustvo života."

And I said, "Really?

Zapitao sam: "Stvarno?

Because isn't that easy?

Jer, znate, nije li to lako?

I mean, we have life.

Mislim, mi imamo život.

Can't you apply a definition,

Zar ne možete da primenite definiciju,

for example, a Supreme Court-like definition of life?"

definiciju kakvu bi dao Vrhovni Sud, na primer?"

And then I thought about it a little bit, and I said,

Razmišljao sam malo o tome i rekao:

"Well, is it really that easy?

"Da li je zaista toliko lako?

Because, yes, if you see something like this,

Jer, da, kada vidite ovako nešto,

then all right, fine, I'm going to call it life --

onda je u redu, to jeste život,

no doubt about it.

nema sumnje u to.

But here's something."

Ali evo nečega."

And he goes, "Right, that's life too. I know that."

On će na to: "Da, u redu, i to je život, znam to."

Except, if you think that life is also defined by things that die,

Ali, ako mislite da se život definiše

kao nešto što na kraju umire

you're not in luck with this thing,

onda s ovim nećete imati sreće,

because that's actually a very strange organism.

jer je ovo jedan vrlo čudan organizam.

It grows up into the adult stage like that

On postaje odrasla jedinka,

and then goes through a Benjamin Button phase,

a onda prolazi kroz fazu "Bendžamin Baton"

and actually goes backwards and backwards until it's like a little embryo again,

zapravo, vraća se unazad

dok ponovo ne postane mali embrion,

and then actually grows back up, and back down and back up --

a onda poraste ponovo, pa se vrati unazad, pa ponovo raste - kao jo-jo,

sort of yo-yo -- and it never dies.

i nikad ne umire.

So it's actually life,

Tako da, to jeste život,

but it's actually not as we thought life would be.

ali nije baš

onakav kakvim ga zamišljamo.

And then you see something like that.

A onda vidite nešto kao što je ovo.

And he was like, "My God, what kind of a life form is that?"

On je upitao: "Bože, kakav je pa ovo oblik života?"

Anyone know?

Zna li neko?

It's actually not life, it's a crystal.

Ovo zapravo nije živo, to je kristal.

So once you start looking and looking at smaller and smaller things --

Dakle, jednom kada počnete da gledate i gledate

u sve manje i manje stvari...

so this particular person wrote a whole article and said,

Tako je ova osoba

napisala čitav članak, rekavši: "Hej, ovo su bakterije."

"Hey, these are bacteria."

Except, if you look a little bit closer,

Ali, kada pogledate malo bolje,

you see, in fact, that this thing is way too small to be anything like that.

videćete, u stvari, da je ovo suviše malo da bi bilo tako nešto.

Dakle, on je bio uveren,

So he was convinced, but, in fact, most people aren't.

ali, zapravo, većina ljudi nije bila.

And then, of course, NASA also had a big announcement,

A onda, naravno

NASA je objavila,

and President Clinton gave a press conference,

i predsednik Klinton je imao konferenciju za štampu

about this amazing discovery of life in a Martian meteorite.

vezanu za ovo neverovatno otkriće

života na marsovskom meteoritu.

Except that nowadays, it's heavily disputed.

Ipak, danas, ovo otkriće je predmet rasprave.

If you take the lesson of all these pictures,

Ako izvučete pouku iz svih ovih slika,

then you realize, well, actually, maybe it's not that easy.

shvatićete da ovo zapravo možda i nije tako lako.

Maybe I do need a definition of life

Možda nam i treba

neka definicija života

in order to make that kind of distinction.

kako bismo napravili razliku.

So can life be defined?

Pa može li život da se definiše?

Well how would you go about it?

Kako biste vi to uradili?

Well of course, you'd go to Encyclopedia Britannica and open at L.

Naravno,

uzeli biste Enciklopediju Britaniku i otvorili na slovo L.

No, of course you don't do that; you put it somewhere in Google.

Ne, naravno, ne biste uradili to, već biste izguglali.

And then you might get something.

Tada biste možda dobili nešto.

(Laughter)

And what you might get --

A ako od toga što dobijete,

and anything that actually refers to things that we are used to,

sve što govori o stvarima na koje smo navikli

you throw away.

odbacite,

And then you might come up with something like this.

dobićete nešto ovako.

And it says something complicated with lots and lots of concepts.

Ovo vam govori nešto komplikovano

i sadrži puno različitih koncepata.

Who on Earth would write something as convoluted and complex and inane?

Ko bi na ovom svetu napisao nešto

ovako nategnuto i kompleksno

i blesavo?

Oh, it's actually a really, really, important set of concepts.

No, to je zapravo veoma, veoma važan skup koncepata.

So I'm highlighting just a few words

Istaći ću samo nekoliko reči,

and saying definitions like that rely on things

a davanje takvih definicija

oslanja se na stvari koje nisu zasnovane

that are not based on amino acids or leaves or anything that we are used to,

na aminokiselinama ili listovima

ili na bilo šta na šta smo navikli,

but in fact on processes only.

nego isključivo na procese.

And if you take a look at that,

Ako bacite pogled na to

this was actually in a book that I wrote that deals with artificial life.

videćete da je to iz moje knjige koja se bavi veštačkim životom.

And that explains why that NASA manager was actually in my office to begin with.

To objašnjava šta je taj službenik NASA-e uopšte radio u mojoj kancelariji.

Because the idea was that, with concepts like that,

Zamisao je bila da sa takvim konceptima

maybe we can actually manufacture a form of life.

možda i možemo da napravimo

oblik života.

And so if you go and ask yourself, "What on Earth is artificial life?",

A ako se pitate:

"Šta je, zaboga, veštački život?

let me give you a whirlwind tour of how all this stuff came about.

pustite me da vam na brzinu pokažem

kako je do svega ovoga došlo.

And it started out quite a while ago,

Počelo je prilično davno

when someone wrote one of the first successful computer viruses.

kada je neko napisao

jedan od prvih uspešnih komjuterskih virusa.

And for those of you who aren't old enough,

Za one koji nisu dovoljno stari,

you have no idea how this infection was working --

nemate pojma kako je ova infekcija funkcionisala,

namely, through these floppy disks.

naime, preko disketa.

But the interesting thing about these computer virus infections

Ono što je zanimljivo kod ovih kompjuterskih virusnih infekcija

was that, if you look at the rate at which the infection worked,

je to da, ako pogledate nivoe aktivnosti ovih infekcija,

they show this spiky behavior that you're used to from a flu virus.

dobićete ovaj talasasti prikaz

kakav smo navikli da vidimo kod virusa gripa.

And it is in fact due to this arms race

Ovo je rezultat "nadmetanja u naoružanju"

between hackers and operating system designers

između hakera i dizajnera operativnih sistema,

that things go back and forth.

zato sve ide ovako napred-nazad.

And the result is kind of a tree of life of these viruses,

Rezultat je neka vrsta porodičnog stabla

ovih virusa

a phylogeny that looks very much like the type of life

prikaz razvoja koji prilično podseća na prikaze

that we're used to, at least on the viral level.

razvoja živog sveta na koje smo navikli, barem na nivou virusa.

So is that life?

Je li to, dakle, život? Ne, ako mene pitate.

Not as far as I'm concerned.

Why? Because these things don't evolve by themselves.

Zašto? Zato što ove stvari ne evoluiraju same od sebe.

In fact, they have hackers writing them.

Postoje hakeri koji ih pišu.

But the idea was taken very quickly a little bit further,

Ipak, ideja je vrlo brzo uznapredovala

when a scientist working at the Santa Fe Institute decided,

kada je jedan naučnik koji je radio u Naučnom institutu rekao:

"Why don't we try to package these little viruses

"Zašto ne probamo da spakujemo ove male viruse

in artificial worlds inside of the computer

u veštačke svetove unutar kompjutera

and let them evolve?"

i pustimo ih da evoluiraju?"

And this was Steen Rasmussen.

Taj čovek je bio Stin Rasmusen.

And he designed this system, but it really didn't work,

On je dizajnirao ovaj sistem, ali on zapravo nije radio,

because his viruses were constantly destroying each other.

jer su njegovi virusi stalno uništavali jedni druge.

But there was another scientist who had been watching this, an ecologist.

Sve ovo je posmatrao drugi naučnik, ekolog.

Otišavši kući jednog dana, rekao je: "Znam kako da rešim ovo."

And he went home and says, "I know how to fix this."

And he wrote the Tierra system,

Rezultat je bio "Tierra" sistem,

and, in my book,

i u svojoj knjizi sam rekao da je to jedan od prvih

is in fact one of the first truly artificial living systems --

zaista veštačkih "živih" sistema -

except for the fact that these programs didn't really grow in complexity.

samo što ti programi nisu zaista postajali složeniji.

So having seen this work, worked a little bit on this,

Videvši ovaj rad i poradivši malo na tome,

this is where I came in.

uključio sam se u celu stvar.

And I decided to create a system that has all the properties

Rešio sam da napravim sistem

koji sadrži sve potrebne osobine

that are necessary to see, in fact, the evolution of complexity,

koje dovode do evolucije složenosti,

more and more complex problems constantly evolving.

sve složenije i složenije probleme koji konstantno evoluiraju.

And of course, since I really don't know how to write code, I had help in this.

Naravno, pošto ja zaista ne umem da sastavim kod, imao sam pomoć.

Imao sam dvojicu studenata

I had two undergraduate students

at California Institute of Technology that worked with me.

sa Kalifornijskog Instituta za Tehnologiju koji su radili za mene.

That's Charles Ofria on the left, Titus Brown on the right.

Sa leve strane je Čarls Ofria, sa desne Tajtus Braun.

They are now, actually, respectable professors

Oni su danas ugledni profesori

at Michigan State University,

na Državnom univerzitetu u Mičigenu,

but I can assure you, back in the day, we were not a respectable team.

ali, uverevam vas, u to vreme,

mi nismo bili ugledan tim.

And I'm really happy that no photo survives

Drago mi je što nijedna fotografija

of the three of us anywhere close together.

nas trojice zajedno nije sačuvana.

But what is this system like?

Ali kakav je ovaj sistem?

Well I can't really go into the details,

Ne mogu baš da detaljišem,

but what you see here is some of the entrails.

ali ovde možete da vidite neke od elemenata.

But what I wanted to focus on is this type of population structure.

Ono na šta sam hteo da se fokusiram

je šema strukture populacije.

There's about 10,000 programs sitting here.

Ovde se nalazi oko 10.000 programa.

And all different strains are colored in different colors.

Različite vrste su obojene različitim bojama.

And as you see here, there are groups that are growing on top of each other,

Kao što vidite, grupe njih rastu jedna preko druge,

because they are spreading.

šire se.

Any time there is a program that's better at surviving in this world,

Kad god se pojavi program

koji bolje preživljava u ovom svetu,

due to whatever mutation it has acquired,

koja god mutacija da se pojavila kod njega,

it is going to spread over the others and drive the others to extinction.

raširiće se preko ostalih i dovesti ih do istrebljenja.

Pokazaću vam film u kome se vidi ta vrsta dinamike.

So I'm going to show you a movie

where you're going to see that kind of dynamic.

Ovakvi eksperimenti su počeli

And these kinds of experiments are started with programs that we wrote ourselves.

sa programima koje smo mi sami napisali.

We write our own stuff, replicate it, and are very proud of ourselves.

Pisali smo sopstvene programe, umnožavali ih,

i veoma smo ponosni na sebe.

And we put them in, and what you see immediately

Stavili smo ih unutra i, kao što se odmah vidi,

is that there are waves and waves of innovation.

javljaju se talasi i talasi inovacije.

By the way, this is highly accelerated,

Usput, ovo je vrlo ubrzano,

so it's like a 1000 generations a second.

nekih hiljadu generacija u sekundi.

But immediately, the system goes like, "What kind of dumb piece of code was this?

Ali vrlo brzo, sistem kaže:

"Kakva je sad ovo glupost od koda?

This can be improved upon in so many ways, so quickly."

Ovo se može unaprediti na toliko načina

i to veoma brzo."

So you see waves of new types taking over the other types.

Tako da vidite talase novih tipova

kako preovladavaju nad drugim tipovima.

And this type of activity goes on for quite a while,

Ovakva aktivnost traje prilično dugo,

until the main easy things have been acquired by these programs.

sve dok svi programi ne razviju one glavne lake funkcije.

And then, you see sort of like a stasis coming on

Onda vidite nešto kao stagnaciju

where the system essentially waits

u toku koje sistem čeka

for a new type of innovation, like this one,

neku novu inovaciju, kao što je ova,

which is going to spread over all the other innovations that were before

koja će se proširiti

i nadvladati druge inovacije koje su tu bile ranije,

and is erasing the genes that it had before,

obrisati gene koji su bili tu ranije

until a new type of higher level of complexity has been achieved.

sve dok se novi, složeniji, tip ne pojavi.

And this process goes on and on and on.

Ovaj proces traje i traje i traje.

So what we see here

Dakle, ono što vidimo ovde

is a system that lives in very much the way we're used to how life goes.

jeste sistem koji funkcioniše

na prilično sličan način na koji smo navikli da život funkcioniše.

But what the NASA people had asked me really was,

Ipak, ono što su me ljudi iz NASA-e zapravo pitali

"Do these guys have a biosignature?

bilo je: "Da li ova "stvorenja"

daju znake života?

Can we measure this type of life?

Možemo li da "izmerimo" ovaj oblik života?

Because if we can,

Jer, ako možemo,

maybe we have a chance of actually discovering life somewhere else

možda imamo šansu da zapravo otkrijemo život negde drugde

without being biased by things like amino acids."

i da pritom ne budemo ograničeni

stvarima kakve su aminokiseline."

So I said, "Well, perhaps we should construct a biosignature

Ja sam rekao: "Pa, možda mogu da konstruišem

prikaz znakova života

based on life as a universal process.

zasnovan na životu kao univerzalnom procesu.

In fact, it should perhaps make use of the concepts that I developed

Zapravo, taj prikaz može da koristi koncepte koje sam razvio

just in order to sort of capture what a simple living system might be."

samo kako bih zabeležio

šta bi jednostavan živi sistem mogao da predstavlja."

And the thing I came up with --

Ono što mi je palo na pamet,

I have to first give you an introduction about the idea,

da napravim uvod u ideju,

and maybe that would be a meaning detector,

bi zapravo bio neki detektor značenja,

rather than a life detector.

pre nego detektor života.

And the way we would do that --

Način na koji bismo to postigli --

I would like to find out how I can distinguish text

recimo, želim da saznam kako da razlikujem

that was written by a million monkeys, as opposed to text that is in our books.

tekst koji je napisalo milion majmuna,

od teksta koji je u knjigama.

And I would like to do it in such a way

I želeo bih to da uradim na takav način

that I don't actually have to be able to read the language,

da uopšte i ne moram da znam da čitam na tom jeziku,

because I'm sure I won't be able to.

pošto sam siguran da neću znati.

As long as I know that there's some sort of alphabet.

Uvek mora da postoji neka vrsta alfabeta.

Dakle ovo je nivo učestalosti,

So here would be a frequency plot

of how often you find each of the 26 letters of the alphabet

tj. koliko često se javlja

svako od 26 slova alfabeta

in a text written by random monkeys.

u tekstu koji su napisali neki majmuni.

And obviously, each of these letters comes off about roughly equally frequent.

Očigledno, svako od ovih slova

javlja se otprilike podjednako često.

But if you now look at the same distribution in English texts,

Ali ako pogledate distribuciju slova u tekstovima na engleskom,

it looks like that.

nivo učestalosti je ovakav.

And I'm telling you, this is very robust across English texts.

Kažem vam, ovaj nivo učestalosti u tekstovima na engleskom je vrlo stalan.

And if I look at French texts, it looks a little bit different,

Ako bi pogledali tekstove na francuskom, bilo bi malo drugačije,

or Italian or German.

kao i u tekstovima na italijanskom ili nemačkom.

They all have their own type of frequency distribution,

U svakom su slova drugačije distribuirana,

but it's robust.

ali nivo učestalosti je stalan.

It doesn't matter whether it writes about politics or about science.

Nije bitno da li tekst govori o politici ili o nauci,

da li je u pitanju poezija

It doesn't matter whether it's a poem or whether it's a mathematical text.

ili tekst o matematici,

It's a robust signature,

ova slika je vrlo robusna i stabilna.

and it's very stable.

As long as our books are written in English --

Dok god pišemo knjige na engleskom,

a ljudi ih stalno iznova pišu i umnožavaju,

because people are rewriting them and recopying them --

it's going to be there.

takva slika će biti prisutna.

So that inspired me to think about, well, what if I try to use this idea

To me je inspirisalo da razmislim o sledećem -

dakle, šta ako pokušam da primenim ovu ideju,

in order, not to detect random texts from texts with meaning,

ne da bih razlučio nasumične tekstove

od onih koji imaju značenje,

but rather detect the fact that there is meaning

već da bih otkrio da li postoji značenje

in the biomolecules that make up life.

u biomolekulima koji sačinjavaju život.

But first I have to ask:

Prvo moram da se zapitam:

what are these building blocks,

šta su uopšte ove kockice, ovaj alfabet, ovi elementi koje sam vam pokazao?

like the alphabet, elements that I showed you?

Well it turns out, we have many different alternatives

Ispostavilo se da ima više različitih zamena

for such a set of building blocks.

za ovaj set kockica.

We could use amino acids,

To mogu biti aminokiseline,

we could use nucleic acids, carboxylic acids, fatty acids.

nukleinske kiseline, karboksilne kiseline, masne kiseline.

In fact, chemistry's extremely rich, and our body uses a lot of them.

Zapravo, hemija je izuzetno bogata, i naše telo koristi mnogo hemikalija.

So that we actually, to test this idea,

Dakle, kako bismo testirali ovu ideju

first took a look at amino acids and some other carboxylic acids.

morali smo prvo da ispitamo aminokiseline i neke druge karboksilne kiseline.

And here's the result.

I evo rezultata.

Here is, in fact, what you get

Evo, ovo se dobija

if you, for example, look at the distribution of amino acids

kada, na primer, ispitate distribuciju aminokiselina

on a comet or in interstellar space or, in fact, in a laboratory,

na nekoj kometi ili u međuzvezdanom prostoru

ili u laboratoriji

where you made very sure that in your primordial soup,

za koju ste sigurni

da u njoj nema ničeg živog.

there is no living stuff in there.

What you find is mostly glycine and then alanine

Ono što ćete naći su uglavnom glicin i alanin

and there's some trace elements of the other ones.

a ostalih kiselina ima u tragovima.

That is also very robust --

Ova slika je takođe vrlo konstantna -

what you find in systems like Earth

ovo je ono što bismo našli u sistemima nalik Zemlji

where there are amino acids, but there is no life.

u kojima ima aminokiselina,

ali nema života.

But suppose you take some dirt and dig through it

Ali šta ako bismo uzeli malo zemlje

i kopali malo po njoj

and then put it into these spectrometers,

i onda je stavili u ovaj spektrometar?

because there's bacteria all over the place;

Pošto ima bakterija na sve strane.

or you take water anywhere on Earth,

Isti rezultat bi bio i sa vodom uzetom bilo gde na Zemlji,

because it's teaming with life,

kada bi se sprovela ista analiza,

and you make the same analysis;

jer je i ona prepuna života;

the spectrum looks completely different.

spektar bi izgledao potpuno drugačije.

Of course, there is still glycine and alanine,

Naravno, glicin i alanin bi još uvek bili tu,

but in fact, there are these heavy elements, these heavy amino acids,

ali bilo bi i teških elemenata, teških aminokiselina,

that are being produced because they are valuable to the organism.

koje se proizvode

zato što su od značaja za život organizma.

And some other ones that are not used in the set of 20,

Neke druge

koje ne spadaju u dvadeset esencijalnih,

they will not appear at all in any type of concentration.

se uopšte ne bi pojavile ni u kojoj koncentraciji.

So this also turns out to be extremely robust.

Dakle, i ova slika je konstantna.

It doesn't matter what kind of sediment you're using to grind up,

Nije bitno koji sediment je u pitanju,

da li su u pitanju bakterije ili neke biljke ili životinje.

whether it's bacteria or any other plants or animals.

Anywhere there's life,

Gde god ima života

you're going to have this distribution,

imaćete ovakvu distribuciju,

as opposed to that distribution.

a ne ovakvu.

And it is detectable not just in amino acids.

Ove razlike možemo očitati ne samo kada su aminokiseline u pitanju.

Now you could ask:

Sada se možda pitate:

Well, what about these Avidians?

dakle šta sa ovim "Avidijancima"?

The Avidians being the denizens of this computer world

"Avidijanci" su stanovnici kompjuterskog sveta

where they are perfectly happy replicating and growing in complexity.

u kome su savršeno srećni što se umnožavaju i postaju sve složeniji.

So this is the distribution that you get if, in fact, there is no life.

Dakle, ovo je prikaz distribucije koji dobijamo

u slučaju da života nema.

They have about 28 of these instructions.

Oni imaju 28 ovakvih instrukcija,

And if you have a system where they're being replaced one by the other,

i ukoliko imamo sistem u kome se one javljaju jedna za drugom,

sistem nema značenja - kao majmuni sa kucaćim mašinama.

it's like the monkeys writing on a typewriter.

Each of these instructions appears with roughly the equal frequency.

Svaka od instrukcija se pojavljuje

otprilike podjednako često.

But if you now take a set of replicating guys

Ali ako uzmemo skup ovih stvorenja koja se množe

like in the video that you saw,

kao na snimku koji ste videli,

it looks like this.

prikaz distribucije izgleda ovako.

So there are some instructions

Dakle, postoje neke instrukcije

that are extremely valuable to these organisms,

koje su izuzetno važne za ove "organizme",

and their frequency is going to be high.

i one će se javljati učestalije.

And there's actually some instructions that you only use once, if ever.

A ima i onih instrukcija

koje se koriste samo jednom, ili nikad.

So they are either poisonous

One su, dakle, ili otrovne, ili ih treba koristiti ređe

or really should be used at less of a level than random.

nego što bi se pojavljivale kada bi sve bilo nasumično.

In this case, the frequency is lower.

Nivo učestalosti ovih instrukcija je niži.

And so now we can see, is that really a robust signature?

Sada možemo da vidimo da li zaista postoji neka šema.

I can tell you indeed it is,

Mogu vam reći da postoji,

because this type of spectrum, just like what you've seen in books,

jer smo ovakav spektar videli na primeru sa knjigama,

and just like what you've seen in amino acids,

kao i na primeru sa aminokiselinama,

it doesn't really matter how you change the environment,

i ne menja se kada promenite okruženje, veoma je postojan;

it's very robust, it's going to reflect the environment.

i oslikava okruženje.

Pokazaću vam jedan mali eksperiment koji smo napravili.

So I'm going to show you now a little experiment that we did.

Moram da objasnim -

And I have to explain to you,

na vrhu ovog grafikona

the top of this graph

shows you that frequency distribution that I talked about.

prikazana je učestalost distribucije elemenata o kojoj sam pričao.

Here, that's the lifeless environment

Ovde imamo okolinu bez života

where each instruction occurs at an equal frequency.

gde se svaka od instrukcija ponavlja

podjednako često.

And below there, I show, in fact, the mutation rate in the environment.

A ispod je prikazan

nivo promene učestalosti instrukcija u okolini.

And I'm starting this at a mutation rate that is so high

Počeću eksperiment sa nivoom promene dovoljno visokim

that even if you would drop a replicating program

da, čak i ako bismo ubacili

program koji se umnožava

that would otherwise happily grow up to fill the entire world,

i koji bi inače rado porastao

i ispunio čitav svet,

if you drop it in, it gets mutated to death immediately.

on bi u ovom slučaju "umro" na licu mesta.

So there is no life possible at that type of mutation rate.

Dakle, život je nemoguć

kada je nivo mutacije ovakav.

But then I'm going to slowly turn down the heat, so to speak,

Ali ako polako smanjim temperaturu, da tako kažem,

and then there's this viability threshold

dolazim do praga održivosti u životu

where now it would be possible for a replicator to actually live.

na kome bi bilo moguće

da program koji se umnožava preživi.

And indeed, we're going to be dropping these guys into that soup all the time.

Dakle, ubacivaćemo ova stvorenja

u ovu čorbu sve vreme.

So let's see what that looks like.

Pogledajmo kako to sve izgleda.

So first, nothing, nothing, nothing.

U početku: ništa, ništa, ništa.

Too hot, too hot.

Vrelo, vrelo.

Now the viability threshold is reached,

Sada je prag održivosti dostignut,

and the frequency distribution has dramatically changed

a učestalost distribucije

značajno izmenjena, tj. stabilizovana.

and, in fact, stabilizes.

And now what I did there

A sada šta sam uradio?

is, I was being nasty, I just turned up the heat again and again.

Pa, bio sam nevaljao, povećao sam temperaturu ponovo.

And of course, it reaches the viability threshold.

I naravno, dostigli smo prag održivosti.

And I'm just showing this to you again because it's so nice.

Pokazujem vam ovo ponovo jer je mnogo lepo.

You hit the viability threshold.

Dostigli smo prag održivosti.

The distribution changes to "alive!"

Prikaz distribucije instrukcija se promeni u: "Živo!"

And then, once you hit the threshold

A onda, ako ponovo dođemo do tačke

where the mutation rate is so high that you cannot self-reproduce,

na kojoj je nivo mutacije toliko visok

da se programi ne mogu samoumnožiti,

informacije se ne mogu preneti

you cannot copy the information forward to your offspring

na potomstvo

without making so many mistakes that your ability to replicate vanishes.

bez pravljenja toliko grešaka

da sama sposobnost umnožavanja nestaje.

And then, that signature is lost.

Taj znak života je time izgubljen.

What do we learn from that?

Šta možemo zaključiti iz toga?

Well, I think we learn a number of things from that.

Pa, mnogo toga.

One of them is,

Između ostalog, zaključićemo

if we are able to think about life in abstract terms --

da, ako smo u stanju da zamislimo život

u apstraktnom smislu,

and we're not talking about things like plants,

ne kao biljke,

and we're not talking about amino acids,

aminokiseline

and we're not talking about bacteria,

ili bakterije,

but we think in terms of processes --

već kao skup procesa,

then we could start to think about life

možemo početi da gledamo na život

not as something that is so special to Earth,

ne kao na nešto isključivo svojstveno Zemlji,

but that, in fact, could exist anywhere.

već kao nešto što bi moglo postojati bilo gde.

Because it really only has to do with these concepts of information,

Zato što život ima veze,

pre svega, sa konceptima vezanim za informacije,

of storing information within physical substrates --

za skladištenje informacija

u okviru fizičkog konteksta -

anything: bits, nucleic acids, anything that's an alphabet --

bitova, nukleinskih kiselina

bilo šta što predstavlja sistem znakova -

and make sure that there's some process

obavezno je i postojanje nekog procesa

so that this information can be stored for much longer than you would expect --

koji omogućava da informacije budu skladištene

mnogo duže nego što biste očekivali

the time scales for the deterioration of information.

da mogu odoleti vremenu.

And if you can do that, then you have life.

Ako omogućimo tako nešto,

dobili smo život.

So the first thing that we learn

Dakle, prvo što smo zaključili

is that it is possible to define life in terms of processes alone,

jeste da je život moguće definisati

i samo kao skup procesa,

without referring at all to the type of things that we hold dear,

bez ikakvog oslanjanja

na stvari na koje smo naviknuti

as far as the type of life on Earth is.

kada je u pitanju zemaljski život.

And that, in a sense, removes us again,

To nas na neki način udaljava,

like all of our scientific discoveries, or many of them --

kao i sva naša velika naučna otkrića ili bar većina njih -

it's this continuous dethroning of man --

postepeno nas skida sa trona

naših ubeđenja kako smo posebni jer smo živi.

of how we think we're special because we're alive.

Well, we can make life; we can make life in the computer.

Dakle, možemo da napravimo život. Barem na kompjuteru.

Granted, it's limited,

Naravno, to je ograničen život,

but we have learned what it takes in order to actually construct it.

ali smo tako naučili šta nam sve treba

da bismo ga konstruisali.

And once we have that,

Jednom kad to budemo savladali

then it is not such a difficult task anymore

više neće biti tako teško zamisliti

to say, if we understand the fundamental processes

da, pošto razumemo fundamentalne procese

that do not refer to any particular substrate,

koji se ne odnose ni na jedan određeni kontekst,

then we can go out and try other worlds,

možemo otići odavde

i ispitati druge svetove,

figure out what kind of chemical alphabets might there be,

otkriti kakvi bi hemijski alfabeti tamo mogli da postoje,

figure enough about the normal chemistry, the geochemistry of the planet,

saznati nešto o njihovom hemijskom sastavu,

odnosno geohemiji te planete,

so that we know what this distribution would look like in the absence of life,

kako bismo znali kako nivoi distribucije izgledaju

u odsustvu života,

and then look for large deviations from this --

tada bismo mogli tragati za odstupanjima od toga -

this thing sticking out, which says, "This chemical really shouldn't be there."

ukoliko naiđemo na nešto što se izdvaja, recimo:

"Ovoj hemikaliji ovde nije mesto."

Now we don't know that there's life then,

Nećemo tada biti sigurni da tu ima života,

but we could say,

ali moći ćemo da kažemo:

"Well at least I'm going to have to take a look very precisely at this chemical

"Ispitaću ovu hemikaliju vrlo pažljivo

and see where it comes from."

da vidim odakle potiče."

And that might be our chance of actually discovering life

To može biti naša šansa da otkrijemo život

when we cannot visibly see it.

i kada život ne bude bio očigledan.

And so that's really the only take-home message that I have for you.

Dakle, to je jedina poruka koju želim

da ponesete odavde.

Life can be less mysterious than we make it out to be

Život postaje manje misteriozan

nego što nam se čini

when we try to think about how it would be on other planets.

kada pokušamo da ga zamislimo na drugim planetama.

And if we remove the mystery of life,

Ako uklonimo veo misterije sa naše predstave o životu,

then I think it is a little bit easier for us to think about how we live,

postaće nam lakše

da razmišljamo o tome kako mi živimo,

and how perhaps we're not as special as we always think we are.

i shvatićemo da možda nismo toliko posebni kao što smo oduvek mislili.

And I'm going to leave you with that.

Mislite o tome.

I hvala vam puno.

And thank you very much.

(Applause)

(Aplauz)