David Deutsch: A new way to explain explanation

Prevodilac: Vladimir Milosevic Lektor: Ivana Krivokuća

I'm sure that,

Siguran sam da su, tokom stotinak hiljada godina

throughout the 100,000-odd years of our species' existence

postojanja naše vrste,

and even before,

a čak i pre toga,

our ancestors looked up at the night sky and wondered what stars are --

naši preci gledali u noćno nebo

i pitali se šta su zvezde.

wondering, therefore,

Pitali su se, dakle,

how to explain what they saw

kako da objasne ono što su videli

in terms of things unseen.

preko stvari koje nisu videli, neviđenih stvari.

OK, so, most people only wondered that occasionally, like today,

Naravno, većina ljudi se samo pitala o tome povremeno, kao i danas,

in breaks from whatever normally preoccupied them.

u pauzama između čega god

što ih je uobičajeno preokupiralo.

But what normally preoccupied them also involved yearning to know.

Ali, ono što ih je obično preokupiralo

je takođe uključivalo čežnju za znanjem.

They wished they knew

Oni su želeli da znaju

how to prevent their food supply from sometimes failing,

kako da spreče da im snabdevanje hranom

povremeno zakaže,

and how they could rest when they were tired

i kako da se odmore kada su bili umorni,

without risking starvation,

bez rizika umiranja od gladi,

be warmer, cooler, safer,

kako da im bude toplije, svežije, bezbednije,

in less pain.

sa manje bola.

I bet those prehistoric cave artists would have loved to know

Kladim se da su ti praistorijski pećinski umetnici

stvarno voleli da znaju

how to draw better.

kako da bolje crtaju.

(Laughter)

U svakom aspektu svojih života,

In every aspect of their lives,

they wished for progress, just as we do.

želeli su napredak, baš kao i mi.

But they failed, almost completely, to make any.

Ali propali su, gotovo potpuno, u pokušajima da ostvare bilo kakav.

They didn't know how to.

Nisu znali kako.

Discoveries like fire happened so rarely

Otkrića kao što je vatra

su se dešavala tako retko, da sa gledišta pojedinca,

that, from an individual's point of view,

the world never improved.

svet nije nikada napredovao.

Nothing new was learned.

Ništa novo nije bivalo naučeno.

The first clue to the origin of starlight

Prvi nagoveštaj o poreklu svetla zvezda

happened as recently as 1899:

dogodio se gotovo juče, 1899: radioaktivnost.

radioactivity.

And within 40 years,

U roku od 40 godina,

physicists discovered the whole explanation,

fizičari su otkrili celo objašnjenje,

expressed, as usual, in elegant symbols.

izraženo, kao i obično, kroz elegantne simbole.

But never mind the symbols.

Ali, pustimo simbole.

Think how many discoveries they represent.

Pomislite koliko mnogo otkrića

oni predstavljaju.

Nuclei and nuclear reactions, of course.

Jezgra i nuklearne reakcije, naravno.

But isotopes,

Ali i izotope, čestice elektriciteta,

particles of electricity,

antimatter,

antimateriju,

neutrinos,

neutrine,

the conversion of mass to energy -- that's E=mc2 --

pretvaranje mase u energiju - odnosno, E=mc^2 -

gamma rays,

gama zrake,

transmutation.

transmutaciju.

That ancient dream that had always eluded the alchemists

Taj drevni san koji je uvek izmicao alhemičarima

was achieved through these same theories

postignut je kroz iste ove teorije

that explained starlight and other ancient mysteries

koje su objasnile svetlost zvezda,

i druge drevne misterije,

and new, unexpected phenomena.

i nove, neočekivane pojave.

That all that, discovered in 40 years,

To što sve to, otkriveno za 40 godina,

had not been in the previous hundred thousand

nije bilo otkriveno u prethodnih sto hiljada godina,

was not for lack of thinking

nije zbog nedostatka razmišljanja

about stars and all those other urgent problems they had.

o zvezdama i svim tim drugim gorućim problemima koje su imali.

They even arrived at answers, such as myths,

Čak su i dolazili do odgovora,

kao što su mitovi,

that dominated their lives,

koji su dominirali njihovim životima,

yet bore almost no resemblance to the truth.

a nisu imali skoro nikakve sličnosti

sa istinom.

The tragedy of that protracted stagnation

Tragedija te produžene stagnacije

isn't sufficiently recognized, I think.

nije dovoljno prepoznata, ja mislim.

These were people with brains of essentially the same design

To su bili ljudi sa mozgovima

suštinski istog dizajna

that eventually did discover all those things.

kakav na kraju jeste otkrio sve ove stvari.

But that ability to make progress

Ali sposobnost da se postigne napredak

remained almost unused,

je ostala skoro nekorišćena,

until the event that revolutionized the human condition

sve do događaja

koji je potpuno preokrenuo ljudske okolnosti

i promenio univerzum.

and changed the universe.

Or so we should hope,

Ili se barem nadajmo da jeste.

because that event was the scientific revolution,

Jer taj događaj je bila

naučna revolucija,

ever since which our knowledge of the physical world

od koje je stalno naše znanje o fizičkom svetu

and of how to adapt it to our wishes

i o načinu kako da ga prilagodimo svojim željama neumoljivo raslo.

has been growing relentlessly.

Now, what had changed?

Sada, šta se to bilo promenilo?

What were people now doing for the first time

Šta su to tada ljudi po prvi put radili

that made that difference between stagnation

što je napravilo tu razliku

između stagnacije

and rapid, open-ended discovery?

i brzog, neograničenog otkrivanja?

How to make that difference

Kako napraviti tu razliku

is surely the most important universal truth

je sigurno najvažnija univerzalna istina

that it's possible to know.

koju je moguće spoznati.

And worryingly, there's no consensus about what it is.

Zabrinjavajuće je, ali nema konsenzusa šta je to.

So, I'll tell you.

Zato, ja ću vam reći.

(Laughter)

Ali moraću prvo da se vratim malo unazad.

But I'll have to backtrack a little first.

Before the scientific revolution,

Pre naučne revolucije,

they believed that everything important, knowable,

verovali su da je sve što je važno, spoznatljivo,

was already known,

već bilo poznato,

enshrined in ancient writings, institutions

utkano u drevnim spisima, institucijama,

and in some genuinely useful rules of thumb --

i u nekim zaista korisnim iskustvenim pravilima -

which were, however, entrenched as dogmas,

ali koja su bila ukorenjena kao dogme,

along with many falsehoods.

zajedno sa mnogim neistinama.

So, they believed that knowledge came from authorities

Oni su verovali da je znanje dolazilo od autoriteta,

that actually knew very little.

koji su u stvari znali vrlo malo.

And therefore,

I zato je napredak

progress depended on learning how to reject

zavisio od učenja kako odbaciti

the authority of learned men, the priests, traditions and rulers,

autoritet učenih ljudi,

sveštenika, tradicija i vladara.

which is why the scientific revolution had to have a wider context:

I zbog toga je naučna revolucija

morala da ima širi kontekst.

the Enlightenment, a revolution in how people sought knowledge,

Prosvetiteljstvo, revolucija u načinu

kako su ljudi tražili znanje,

trying not to rely on authority.

pokušavajući da se ne oslanjaju na autoritet.

"Take no one's word for it."

„Nikome nemojte verovati na reč.“

But that can't be what made the difference.

Ali to ne može biti ono što je napravilo razliku.

Authorities had been rejected before, many times.

Autoriteti su odbacivani i ranije, mnogo puta.

And that rarely, if ever,

I to je retko, ako i ikada,

caused anything like the scientific revolution.

prouzrokovalo bilo šta nalik naučnoj revoluciji.

At the time, what they thought distinguished science

U to vreme, ono što su smatrali

da izdvaja nauku

was a radical idea about things unseen,

bila je radikalna ideja o neviđenim stvarima,

known as empiricism --

poznata kao empiricizam.

all knowledge derives from the senses.

Sve znanje proizlazi iz čula.

Well, we've seen that that can't be true.

Pa, videli smo da to ne može biti istina.

It did help by promoting observation and experiment.

Jeste pomoglo promovišući

posmatranje i eksperiment.

But, from the outset,

Ali, od početka je bilo očigledno

it was obvious that there was something horribly wrong with it.

da ima nešto užasno pogrešno u tome.

Knowledge comes from the senses?

Znanje dolazi od čula.

In what language?

Na kojem jeziku? Sigurno ne na jeziku matematike,

Certainly not the language of mathematics, in which, Galileo rightly said,

na kojem je, kako je Galileo ispravno rekao,

the book of nature is written.

napisana knjiga prirode.

Look at the world.

Pogledajte svet.

You don't see equations carved on the mountainsides.

Vi ne vidite jednačine uklesane na obroncima planina.

If you did, it would be because people had carved them.

Da ih vidite, to bi bilo jer su ih ljudi uklesali.

By the way, why don't we do that?

Uzgred budi rečeno, zašto to ne radimo?

(Laughter)

What's wrong with us?

Šta nije u redu s nama?

(Laughter)

(Smeh)

Empiricism is inadequate

Empiricizam je neodgovarajući, jer,

because, well, scientific theories explain the seen in terms of the unseen.

pa, naučne teorije objašnjavaju viđeno preko neviđenoga.

And the unseen, you have to admit,

A neviđeno, morate priznati,

doesn't come to us through the senses.

ne dolazi do nas kroz čula.

We don't see those nuclear reactions in stars.

Mi ne vidimo te nuklearne reakcije u zvezdama.

We don't see the origin of species.

Ne vidimo poreklo vrsta.

We don't see the curvature of space-time,

Ne vidimo zakrivljenost prostor-vremena,

and other universes.

niti druge svemire.

But we know about those things.

Ali znamo o tim stvarima.

How?

Kako?

Well, the classic empiricist answer is induction --

Pa, klasični odgovor empiricista je indukcija.

the unseen resembles the seen.

Neviđeno nalikuje viđenom.

But it doesn't.

Ali, ne nalikuje.

You know what the clinching evidence was that space-time is curved?

Znate li šta je bio ključni dokaz

da je prostor-vreme zakrivljeno?

It was a photograph -- not of space-time,

To je bila fotografija, ne prostor-vremena,

but of an eclipse, with a dot there rather than there.

već pomračenja, sa tačkom tamo umesto ovde.

And the evidence for evolution?

A dokaz evolucije?

Some rocks and some finches.

Nešto kamenja i nekoliko zeba.

And parallel universes?

A paralelni svemiri? Opet: tačke tamo, umesto ovde, na ekranu.

Again: dots there rather than there, on a screen.

What we see in all these cases

Ono što vidimo, u svim ovim slučajevima,

bears no resemblance to the reality that we conclude is responsible --

ne nosi nikakvu sličnost sa realnošću

za koju zaključujemo da je odgovorna -

samo dugački niz teorijskog rezonovanja

only a long chain of theoretical reasoning and interpretation connects them.

i interpretacija su ono što ih spaja.

"Ah!" say creationists.

„Ah“, kažu kreacionisti,

"So you admit it's all interpretation.

„Dakle, priznajete da je sve interpretacija.

No one's ever seen evolution.

Niko nikada nije video evoluciju.

We see rocks.

Vidimo stene.

You have your interpretation. We have ours.

Vi imate svoje interpretacije. Mi imamo svoje.

Yours comes from guesswork; ours, from the Bible."

Vaše proizilaze iz nagađanja;

a naše iz Biblije.“

But what creationist and empiricists both ignore

Ali, ono što kreacionisti i empiricisti ignorišu

is that, in that sense,

je da, u tom smislu,

no one's ever seen a Bible either,

niko takođe nije ni Bibliju video,

that the eye only detects light, which we don't perceive.

da oko samo detektuje svetlo, koje mi iskustveno ne doživljavamo.

Brains only detect nerve impulses.

Mozgovi samo detektuju nervne impulse.

And they don't perceive even those as what they really are,

I ne doživljavaju čak ni njih kakvi stvarno jesu,

namely electrical crackles.

naime, električna pucketanja.

So we perceive nothing as what it really is.

Dakle, mi ništa iskustveno ne doživljavamo onako kakvo u stvarnosti jeste.

Our connection to reality is never just perception.

Naša veza sa realnošću

nikada nije samo percepcija.

It's always, as Karl Popper put it,

Uvek je, kako je sročio Karl Poper,

theory-laden.

opterećena teorijom.

Scientific knowledge isn't derived from anything.

Naučno znanje se ne izvodi ni iz čega.

Like all knowledge, it's conjectural, guesswork,

Ono je kao i sve znanje.

Pretpostavljeno, nagađajuće,

tested by observation,

testirano opažanjem,

not derived from it.

a ne iz njega izvedeno.

So, were testable conjectures the great innovation

Dakle, jesu li proverljive pretpostavke

that opened the intellectual prison gates?

bile ta velika inovacija koja je otvorila kapije intelektualnog zatvora?

No, contrary to what's usually said, testability is common

Ne. Suprotno onome što se obično govori,

proverljivost je često prisutna

in myths and all sorts of other irrational modes of thinking.

u mitovima i svim vrstama drugih iracionalnih načina razmišljanja.

Any crank claiming the sun will go out next Tuesday

Svaki čudak koji tvrdi da će se sunce ugasiti sledećeg utorka

has got a testable prediction.

ima proverljivo predviđanje.

Consider the ancient Greek myth explaining seasons.

Uzmite u obzir antički grčki mit

koji objašnjava godišnja doba.

Hades, god of the underworld,

Had, bog podzemlja,

otima Persefonu, boginju proleća,

kidnaps Persephone, the goddess of spring,

and negotiates a forced marriage contract, requiring her to return regularly,

i sklapa prisilni bračni ugovor

koji je obavezuje da mu se redovno vraća,

and lets her go.

a zatim je pušta.

And each year,

I svake godine,

she is magically compelled to return.

ona je magično primorana da se vrati.

And her mother, Demeter,

A njena majka, Demetra,

goddess of the earth,

boginja Zemlje,

is sad, and makes it cold and barren.

je tužna, pa je čini hladnom i pustom.

That myth is testable.

Taj mit je proverljiv.

If winter is caused by Demeter's sadness,

Ako je zima prouzrokovana Demetrinom tugom,

then it must happen everywhere on earth simultaneously.

onda se ona mora dešavati svuda na Zemlji istovremeno.

So if the ancient Greeks had only known

Tako, da su antički Grci samo znali da je Australija

that Australia is at its warmest when Demeter is at her saddest ...

najtoplija kada je Demetra najtužnija,

(Laughter)

they'd have known that their theory is false.

znali bi da je njihova teorija pogrešna.

(Laughter)

Pa, šta je bilo pogrešno sa tim mitom,

So, what was wrong with that myth

and with all prescientific thinking?

i sa svim prednaučnim razmišljanjem,

And what, then, made that momentous difference?

i šta je, onda, napravilo tu značajnu razliku?

I think there's one thing you have to care about

Mislim da ima jedna stvar do koje bi trebalo da vam je stalo.

A iz nje proizilazi

and that implies testability, the scientific method,

proverljivost, naučni metod,

the Enlightenment and everything.

prosvetiteljstvo i sve.

And here's the crucial thing:

I evo te ključne stvari.

there is such a thing as a defect in a story.

Postoji nešto kao manjkavost u priči.

I don't just mean a logical defect.

Ne mislim samo na logičku manjkavost. Mislim na loše objašnjenje.

I mean a bad explanation.

What does that mean?

Šta to znači?

Well, an explanation is an assertion about what's there, unseen,

Pa, objašnjenje je tvrdnja o onome što postoji, neviđeno,

that accounts for what's seen;

a što objašnjava ono što je viđeno.

because the explanatory role of Persephone's marriage contract

Jer, objašnjavajuću ulogu

bračnog ugovora Persefone

could be played equally well

moglo bi podjednako dobro da odigra

by infinitely many other ad hoc entities.

beskonačno mnogo drugih

ad hoc entiteta.

Why a marriage contract and not any other reason

Zašto bračni ugovor, a ne neki drugi razlog

for regular annual action?

za redovnu godišnju aktivnost?

Here's one: Persephone wasn't released.

Evo jednog. Persefona nije puštena.

She escaped, and returns every spring to take revenge on Hades,

Pobegla je, i vraća se svakog proleća

kako bi se osvetila Hadu

with her spring powers.

svojim prolećnim moćima.

She cools his domain with spring air,

Ona hladi njegovu okolinu prolećnim vazduhom,

venting heat up to the surface, creating summer.

izbacujući toplotu gore na površinu, stvarajući leto.

That accounts for the same phenomena as the original myth.

To objašnjava isti fenomen kao i izvorni mit.

It's equally testable.

I podjednako je proverljivo.

Yet what it asserts about reality is, in many ways, the opposite.

Ipak, ono što tvrdi o realnosti

je, na mnoge načine, suprotno.

And that's possible

A to je moguće zbog toga što

because the details of the original myth are unrelated to seasons,

detalji izvornog mita

nisu u vezi sa godišnjim dobima,

except via the myth itself.

osim posredstvom samog mita.

This easy variability

Ova laka varijabilnost

is the sign of a bad explanation,

je znak lošeg objašnjenja.

because, without a functional reason

Jer, bez funkcionalnog razloga za preferiranje

to prefer one of countless variants,

jedne od bezbrojnih varijanti,

advocating one of them in preference to the others

braniti jednu od njih, pretpostaviti je drugima,

is irrational.

je iracionalno.

So, for the essence of what makes the difference to enable progress,

Dakle, za suštinu onoga

što pravi razliku da omogući napredak,

seek good explanations,

tražite dobra objašnjenja,

the ones that can't be easily varied,

ona koja se ne mogu jednostavno varirati,

while still explaining the phenomena.

a da još uvek objašnjavaju fenomen.

Now our current explanation of seasons

Sada, naše sadašnje objašnjenje godišnjih doba

is that the Earth's axis is tilted like that,

je da je Zemljina osa nagnuta tako

so each hemisphere tilts towards the sun for half the year,

da se svaka hemisfera naginje prema Suncu polovinu godine,

and away for the other half.

a od Sunca drugu polovinu.

[Not to scale!]

Bolje je staviti i ovo.

Better put that up.

(Laughter)

(Smeh)

That's a good explanation:

To je dobro objašnjenje: teško ga je menjati,

hard to vary,

because every detail plays a functional role.

jer svaki detalj igra funkcionalnu ulogu.

For instance, we know, independently of seasons,

Na primer, znamo, nezavisno od godišnjih doba,

that surfaces tilted away from radiant heat are heated less,

da se površine koje su nagnute dalje

od toplotnog zračenja manje greju,

and that a spinning sphere, in space,

i da rotirajuća kugla, u prostoru,

points in a constant direction.

pokazuje stalno u istom pravcu.

And the tilt also explains

A nagnutost takođe objašnjava

the sun's angle of elevation at different times of year,

ugao elevacije Sunca u različitim delovima godine,

and predicts that the seasons will be out of phase in the two hemispheres.

i predviđa da će godišnja doba

biti van faze u dvema hemisferama.

If they'd been observed in phase,

Da su opažena u fazi,

the theory would have been refuted.

teorija bi bila opovrgnuta.

But now, the fact that it's also a good explanation, hard to vary,

Ali ovako, činjenica da je to i dobro objašnjenje,

teško varijabilno, čini ključnu razliku.

makes the crucial difference.

Da su antički Grci saznali

If the ancient Greeks had found out about seasons in Australia,

o godišnjim dobima u Australiji,

they could have easily varied their myth to predict that.

mogli su lako prilagoditi svoj mit

da to predvidi.

For instance, when Demeter's upset,

Na primer, kada je Demetra uznemirena,

she banishes heat from her vicinity into the other hemisphere,

ona protera vrućinu iz svoje blizine

u drugu hemisferu, gde to stvara leto.

where it makes summer.

So, being proved wrong by observation

I tako, opovrgavanje opažanjem,

and changing their theory accordingly

pa prigodno variranje teorije,

still wouldn't have got the ancient Greeks one jot closer to understanding seasons,

ne bi još uvek antičke Grke

ni za jotu približilo razumevanju godišnjih doba,

because their explanation was bad -- easy to vary.

jer je njihovo objašnjenje bilo loše: jednostavno za variranje.

And it's only when an explanation is good

I samo onda kada je neko objašnjenje dobro

that it even matters whether it's testable.

je uopšte i bitno da li je proverljivo.

If the axis-tilt theory had been refuted,

Da je teorija o nagibu ose opovrgnuta,

its defenders would have had nowhere to go.

njeni proponenti ne bi imali gde.

No easily implemented change

Nijedna jednostavno primenjena varijacija

could make that tilt cause the same seasons in both hemispheres.

ne bi mogla učiniti da nagib

prouzrokuje ista godišnja doba u obe hemisfere.

The search for hard-to-vary explanations is the origin of all progress.

Potraga za teško promenljivim objašnjenjima

je ishodište celokupnog napretka.

It's the basic regulating principle of the Enlightenment.

To je osnovni regulatorni princip

prosvetiteljstva.

So, in science, two false approaches blight progress.

I tako, u nauci,

dva pogrešna pristupa razaraju napredak.

One's well-known: untestable theories.

Jedan je dobro poznat: neproverljive teorije.

But the more important one is explanationless theories.

Ali onaj važniji je - teorije bez objašnjenja.

Whenever you're told that some existing statistical trend will continue

Kada god vam kažu da će se neki postojeći statistički trend nastaviti,

but you aren't given a hard-to-vary account of what causes that trend,

ali vam nije dato i teško varijabilno objašnjenje

o tome šta uzrokuje taj trend,

you're being told a wizard did it.

govore vam da je to čarobnjak uradio.

When you are told that carrots have human rights

Kada vam kažu da šargarepe imaju ljudska prava,

because they share half our genes,

jer dele polovinu naših gena -

but not how gene percentages confer rights -- wizard.

ali ne i kako procenti gena dodeljuju prava - čarobnjak.

When someone announces that the nature-nurture debate

Kada neko objavi da je polemika urođeno-stečeno

has been settled

rešena jer postoje dokazi

because there's evidence that a given percentage of our political opinions

da je dati procenat

naših političkih mišljenja genetski nasleđen,

are genetically inherited,

but they don't explain how genes cause opinions,

ali ne objašnjavaju kako geni prouzrokuju mišljenja,

they've settled nothing.

nisu rešili ništa.

They're saying that our opinions are caused by wizards,

Oni govore da naša mišljenja prouzrokuju čarobnjaci,

a pretpostavimo, i njihova sopstvena.

and presumably, so are their own.

(Laughter)

That the truth consists of hard-to-vary assertions about reality

Da se istina sastoji

od teško varijabilnih tvrdnji o stvarnosti

is the most important fact about the physical world.

je najvažnija činjenica

o fizičkom svetu.

It's a fact that is itself unseen,

To je činjenica koja je i sama neviđena,

yet impossible to vary.

a ipak, nemoguće je varirati je.

Thank you.

Hvala vam.

(Applause)

(Aplauz)