I'm sure that, throughout the 100,000-odd years of our species' existence and even before, our ancestors looked up at the night sky and wondered what stars are -- wondering, therefore, how to explain what they saw in terms of things unseen.
Siguran sam da su, tokom stotinak hiljada godina postojanja naše vrste, a čak i pre toga, naši preci gledali u noćno nebo i pitali se šta su zvezde. Pitali su se, dakle, kako da objasne ono što su videli preko stvari koje nisu videli, neviđenih stvari.
OK, so, most people only wondered that occasionally, like today, in breaks from whatever normally preoccupied them. But what normally preoccupied them also involved yearning to know. They wished they knew how to prevent their food supply from sometimes failing, and how they could rest when they were tired without risking starvation, be warmer, cooler, safer, in less pain. I bet those prehistoric cave artists would have loved to know how to draw better.
Naravno, većina ljudi se samo pitala o tome povremeno, kao i danas, u pauzama između čega god što ih je uobičajeno preokupiralo. Ali, ono što ih je obično preokupiralo je takođe uključivalo čežnju za znanjem. Oni su želeli da znaju kako da spreče da im snabdevanje hranom povremeno zakaže, i kako da se odmore kada su bili umorni, bez rizika umiranja od gladi, kako da im bude toplije, svežije, bezbednije, sa manje bola. Kladim se da su ti praistorijski pećinski umetnici stvarno voleli da znaju kako da bolje crtaju.
(Laughter)
U svakom aspektu svojih života,
In every aspect of their lives, they wished for progress, just as we do. But they failed, almost completely, to make any. They didn't know how to. Discoveries like fire happened so rarely that, from an individual's point of view, the world never improved. Nothing new was learned.
želeli su napredak, baš kao i mi. Ali propali su, gotovo potpuno, u pokušajima da ostvare bilo kakav. Nisu znali kako. Otkrića kao što je vatra su se dešavala tako retko, da sa gledišta pojedinca, svet nije nikada napredovao. Ništa novo nije bivalo naučeno.
The first clue to the origin of starlight happened as recently as 1899: radioactivity. And within 40 years, physicists discovered the whole explanation, expressed, as usual, in elegant symbols. But never mind the symbols. Think how many discoveries they represent. Nuclei and nuclear reactions, of course. But isotopes, particles of electricity, antimatter, neutrinos, the conversion of mass to energy -- that's E=mc2 -- gamma rays, transmutation. That ancient dream that had always eluded the alchemists was achieved through these same theories that explained starlight and other ancient mysteries and new, unexpected phenomena.
Prvi nagoveštaj o poreklu svetla zvezda dogodio se gotovo juče, 1899: radioaktivnost. U roku od 40 godina, fizičari su otkrili celo objašnjenje, izraženo, kao i obično, kroz elegantne simbole. Ali, pustimo simbole. Pomislite koliko mnogo otkrića oni predstavljaju. Jezgra i nuklearne reakcije, naravno. Ali i izotope, čestice elektriciteta, antimateriju, neutrine, pretvaranje mase u energiju - odnosno, E=mc^2 - gama zrake, transmutaciju. Taj drevni san koji je uvek izmicao alhemičarima postignut je kroz iste ove teorije koje su objasnile svetlost zvezda, i druge drevne misterije, i nove, neočekivane pojave.
That all that, discovered in 40 years, had not been in the previous hundred thousand was not for lack of thinking about stars and all those other urgent problems they had. They even arrived at answers, such as myths, that dominated their lives, yet bore almost no resemblance to the truth. The tragedy of that protracted stagnation isn't sufficiently recognized, I think. These were people with brains of essentially the same design that eventually did discover all those things. But that ability to make progress remained almost unused, until the event that revolutionized the human condition and changed the universe.
To što sve to, otkriveno za 40 godina, nije bilo otkriveno u prethodnih sto hiljada godina, nije zbog nedostatka razmišljanja o zvezdama i svim tim drugim gorućim problemima koje su imali. Čak su i dolazili do odgovora, kao što su mitovi, koji su dominirali njihovim životima, a nisu imali skoro nikakve sličnosti sa istinom. Tragedija te produžene stagnacije nije dovoljno prepoznata, ja mislim. To su bili ljudi sa mozgovima suštinski istog dizajna kakav na kraju jeste otkrio sve ove stvari. Ali sposobnost da se postigne napredak je ostala skoro nekorišćena, sve do događaja koji je potpuno preokrenuo ljudske okolnosti i promenio univerzum.
Or so we should hope, because that event was the scientific revolution, ever since which our knowledge of the physical world and of how to adapt it to our wishes has been growing relentlessly. Now, what had changed? What were people now doing for the first time that made that difference between stagnation and rapid, open-ended discovery? How to make that difference is surely the most important universal truth that it's possible to know. And worryingly, there's no consensus about what it is. So, I'll tell you.
Ili se barem nadajmo da jeste. Jer taj događaj je bila naučna revolucija, od koje je stalno naše znanje o fizičkom svetu i o načinu kako da ga prilagodimo svojim željama neumoljivo raslo. Sada, šta se to bilo promenilo? Šta su to tada ljudi po prvi put radili što je napravilo tu razliku između stagnacije i brzog, neograničenog otkrivanja? Kako napraviti tu razliku je sigurno najvažnija univerzalna istina koju je moguće spoznati. Zabrinjavajuće je, ali nema konsenzusa šta je to. 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, they believed that everything important, knowable, was already known, enshrined in ancient writings, institutions and in some genuinely useful rules of thumb -- which were, however, entrenched as dogmas, along with many falsehoods. So, they believed that knowledge came from authorities that actually knew very little. And therefore, progress depended on learning how to reject the authority of learned men, the priests, traditions and rulers, which is why the scientific revolution had to have a wider context: the Enlightenment, a revolution in how people sought knowledge,
Pre naučne revolucije, verovali su da je sve što je važno, spoznatljivo, već bilo poznato, utkano u drevnim spisima, institucijama, i u nekim zaista korisnim iskustvenim pravilima - ali koja su bila ukorenjena kao dogme, zajedno sa mnogim neistinama. Oni su verovali da je znanje dolazilo od autoriteta, koji su u stvari znali vrlo malo. I zato je napredak zavisio od učenja kako odbaciti autoritet učenih ljudi, sveštenika, tradicija i vladara. I zbog toga je naučna revolucija morala da ima širi kontekst.
trying not to rely on authority. "Take no one's word for it." But that can't be what made the difference. Authorities had been rejected before, many times. And that rarely, if ever, caused anything like the scientific revolution. At the time, what they thought distinguished science was a radical idea about things unseen, known as empiricism -- all knowledge derives from the senses. Well, we've seen that that can't be true. It did help by promoting observation and experiment. But, from the outset, it was obvious that there was something horribly wrong with it.
Prosvetiteljstvo, revolucija u načinu kako su ljudi tražili znanje, pokušavajući da se ne oslanjaju na autoritet. „Nikome nemojte verovati na reč.“ Ali to ne može biti ono što je napravilo razliku. Autoriteti su odbacivani i ranije, mnogo puta. I to je retko, ako i ikada, prouzrokovalo bilo šta nalik naučnoj revoluciji. U to vreme, ono što su smatrali da izdvaja nauku bila je radikalna ideja o neviđenim stvarima, poznata kao empiricizam. Sve znanje proizlazi iz čula. Pa, videli smo da to ne može biti istina. Jeste pomoglo promovišući posmatranje i eksperiment. Ali, od početka je bilo očigledno da ima nešto užasno pogrešno u tome.
Knowledge comes from the senses? In what language? Certainly not the language of mathematics, in which, Galileo rightly said, the book of nature is written. Look at the world. You don't see equations carved on the mountainsides. If you did, it would be because people had carved them. By the way, why don't we do that?
Znanje dolazi od čula. Na kojem jeziku? Sigurno ne na jeziku matematike, na kojem je, kako je Galileo ispravno rekao, napisana knjiga prirode. Pogledajte svet. Vi ne vidite jednačine uklesane na obroncima planina. Da ih vidite, to bi bilo jer su ih ljudi uklesali. Uzgred budi rečeno, zašto to ne radimo?
(Laughter)
Šta nije u redu s nama?
What's wrong with us?
(Smeh)
(Laughter)
Empiricism is inadequate because, well, scientific theories explain the seen in terms of the unseen. And the unseen, you have to admit, doesn't come to us through the senses. We don't see those nuclear reactions in stars. We don't see the origin of species. We don't see the curvature of space-time, and other universes. But we know about those things. How?
Empiricizam je neodgovarajući, jer, pa, naučne teorije objašnjavaju viđeno preko neviđenoga. A neviđeno, morate priznati, ne dolazi do nas kroz čula. Mi ne vidimo te nuklearne reakcije u zvezdama. Ne vidimo poreklo vrsta. Ne vidimo zakrivljenost prostor-vremena, niti druge svemire. Ali znamo o tim stvarima. Kako?
Well, the classic empiricist answer is induction -- the unseen resembles the seen. But it doesn't. You know what the clinching evidence was that space-time is curved? It was a photograph -- not of space-time, but of an eclipse, with a dot there rather than there. And the evidence for evolution? Some rocks and some finches. And parallel universes? Again: dots there rather than there, on a screen. What we see in all these cases bears no resemblance to the reality that we conclude is responsible -- only a long chain of theoretical reasoning and interpretation connects them.
Pa, klasični odgovor empiricista je indukcija. Neviđeno nalikuje viđenom. Ali, ne nalikuje. Znate li šta je bio ključni dokaz da je prostor-vreme zakrivljeno? To je bila fotografija, ne prostor-vremena, već pomračenja, sa tačkom tamo umesto ovde. A dokaz evolucije? Nešto kamenja i nekoliko zeba. A paralelni svemiri? Opet: tačke tamo, umesto ovde, na ekranu. Ono što vidimo, u svim ovim slučajevima, ne nosi nikakvu sličnost sa realnošću za koju zaključujemo da je odgovorna - samo dugački niz teorijskog rezonovanja i interpretacija su ono što ih spaja.
"Ah!" say creationists. "So you admit it's all interpretation. No one's ever seen evolution. We see rocks. You have your interpretation. We have ours. Yours comes from guesswork; ours, from the Bible." But what creationist and empiricists both ignore is that, in that sense, no one's ever seen a Bible either, that the eye only detects light, which we don't perceive. Brains only detect nerve impulses. And they don't perceive even those as what they really are, namely electrical crackles. So we perceive nothing as what it really is.
„Ah“, kažu kreacionisti, „Dakle, priznajete da je sve interpretacija. Niko nikada nije video evoluciju. Vidimo stene. Vi imate svoje interpretacije. Mi imamo svoje. Vaše proizilaze iz nagađanja; a naše iz Biblije.“ Ali, ono što kreacionisti i empiricisti ignorišu je da, u tom smislu, niko takođe nije ni Bibliju video, da oko samo detektuje svetlo, koje mi iskustveno ne doživljavamo. Mozgovi samo detektuju nervne impulse. I ne doživljavaju čak ni njih kakvi stvarno jesu, naime, električna pucketanja. Dakle, mi ništa iskustveno ne doživljavamo onako kakvo u stvarnosti jeste.
Our connection to reality is never just perception. It's always, as Karl Popper put it, theory-laden. Scientific knowledge isn't derived from anything. Like all knowledge, it's conjectural, guesswork, tested by observation, not derived from it. So, were testable conjectures the great innovation that opened the intellectual prison gates? No, contrary to what's usually said, testability is common in myths and all sorts of other irrational modes of thinking. Any crank claiming the sun will go out next Tuesday has got a testable prediction.
Naša veza sa realnošću nikada nije samo percepcija. Uvek je, kako je sročio Karl Poper, opterećena teorijom. Naučno znanje se ne izvodi ni iz čega. Ono je kao i sve znanje. Pretpostavljeno, nagađajuće, testirano opažanjem, a ne iz njega izvedeno. Dakle, jesu li proverljive pretpostavke bile ta velika inovacija koja je otvorila kapije intelektualnog zatvora? Ne. Suprotno onome što se obično govori, proverljivost je često prisutna u mitovima i svim vrstama drugih iracionalnih načina razmišljanja. Svaki čudak koji tvrdi da će se sunce ugasiti sledećeg utorka ima proverljivo predviđanje.
Consider the ancient Greek myth explaining seasons. Hades, god of the underworld, kidnaps Persephone, the goddess of spring, and negotiates a forced marriage contract, requiring her to return regularly, and lets her go. And each year, she is magically compelled to return. And her mother, Demeter, goddess of the earth, is sad, and makes it cold and barren. That myth is testable. If winter is caused by Demeter's sadness, then it must happen everywhere on earth simultaneously. So if the ancient Greeks had only known that Australia is at its warmest when Demeter is at her saddest ...
Uzmite u obzir antički grčki mit koji objašnjava godišnja doba. Had, bog podzemlja, otima Persefonu, boginju proleća, i sklapa prisilni bračni ugovor koji je obavezuje da mu se redovno vraća, a zatim je pušta. I svake godine, ona je magično primorana da se vrati. A njena majka, Demetra, boginja Zemlje, je tužna, pa je čini hladnom i pustom. Taj mit je proverljiv. Ako je zima prouzrokovana Demetrinom tugom, onda se ona mora dešavati svuda na Zemlji istovremeno. Tako, da su antički Grci samo znali da je Australija najtoplija kada je Demetra najtužnija,
(Laughter)
znali bi da je njihova teorija pogrešna.
they'd have known that their theory is false.
(Laughter)
Pa, šta je bilo pogrešno sa tim mitom,
So, what was wrong with that myth and with all prescientific thinking? And what, then, made that momentous difference? I think there's one thing you have to care about and that implies testability, the scientific method, the Enlightenment and everything. And here's the crucial thing: there is such a thing as a defect in a story. I don't just mean a logical defect. I mean a bad explanation. What does that mean?
i sa svim prednaučnim razmišljanjem, i šta je, onda, napravilo tu značajnu razliku? Mislim da ima jedna stvar do koje bi trebalo da vam je stalo. A iz nje proizilazi proverljivost, naučni metod, prosvetiteljstvo i sve. I evo te ključne stvari. Postoji nešto kao manjkavost u priči. Ne mislim samo na logičku manjkavost. Mislim na loše objašnjenje. Šta to znači? Pa, objašnjenje je tvrdnja o onome što postoji, neviđeno,
Well, an explanation is an assertion about what's there, unseen, that accounts for what's seen; because the explanatory role of Persephone's marriage contract could be played equally well by infinitely many other ad hoc entities. Why a marriage contract and not any other reason for regular annual action? Here's one: Persephone wasn't released. She escaped, and returns every spring to take revenge on Hades, with her spring powers. She cools his domain with spring air, venting heat up to the surface, creating summer. That accounts for the same phenomena as the original myth. It's equally testable. Yet what it asserts about reality is, in many ways, the opposite. And that's possible because the details of the original myth are unrelated to seasons, except via the myth itself.
a što objašnjava ono što je viđeno. Jer, objašnjavajuću ulogu bračnog ugovora Persefone moglo bi podjednako dobro da odigra beskonačno mnogo drugih ad hoc entiteta. Zašto bračni ugovor, a ne neki drugi razlog za redovnu godišnju aktivnost? Evo jednog. Persefona nije puštena. Pobegla je, i vraća se svakog proleća kako bi se osvetila Hadu svojim prolećnim moćima. Ona hladi njegovu okolinu prolećnim vazduhom, izbacujući toplotu gore na površinu, stvarajući leto. To objašnjava isti fenomen kao i izvorni mit. I podjednako je proverljivo. Ipak, ono što tvrdi o realnosti je, na mnoge načine, suprotno. A to je moguće zbog toga što detalji izvornog mita nisu u vezi sa godišnjim dobima, osim posredstvom samog mita.
This easy variability is the sign of a bad explanation, because, without a functional reason to prefer one of countless variants, advocating one of them in preference to the others is irrational. So, for the essence of what makes the difference to enable progress, seek good explanations, the ones that can't be easily varied, while still explaining the phenomena.
Ova laka varijabilnost je znak lošeg objašnjenja. Jer, bez funkcionalnog razloga za preferiranje jedne od bezbrojnih varijanti, braniti jednu od njih, pretpostaviti je drugima, je iracionalno. Dakle, za suštinu onoga što pravi razliku da omogući napredak, tražite dobra objašnjenja, ona koja se ne mogu jednostavno varirati, a da još uvek objašnjavaju fenomen.
Now our current explanation of seasons is that the Earth's axis is tilted like that, so each hemisphere tilts towards the sun for half the year, and away for the other half.
Sada, naše sadašnje objašnjenje godišnjih doba je da je Zemljina osa nagnuta tako da se svaka hemisfera naginje prema Suncu polovinu godine, a od Sunca drugu polovinu.
[Not to scale!]
Bolje je staviti i ovo.
Better put that up.
(Smeh)
(Laughter)
To je dobro objašnjenje: teško ga je menjati,
That's a good explanation: hard to vary, because every detail plays a functional role. For instance, we know, independently of seasons, that surfaces tilted away from radiant heat are heated less, and that a spinning sphere, in space, points in a constant direction. And the tilt also explains the sun's angle of elevation at different times of year, and predicts that the seasons will be out of phase in the two hemispheres. If they'd been observed in phase, the theory would have been refuted. But now, the fact that it's also a good explanation, hard to vary, makes the crucial difference.
jer svaki detalj igra funkcionalnu ulogu. Na primer, znamo, nezavisno od godišnjih doba, da se površine koje su nagnute dalje od toplotnog zračenja manje greju, i da rotirajuća kugla, u prostoru, pokazuje stalno u istom pravcu. A nagnutost takođe objašnjava ugao elevacije Sunca u različitim delovima godine, i predviđa da će godišnja doba biti van faze u dvema hemisferama. Da su opažena u fazi, teorija bi bila opovrgnuta. Ali ovako, činjenica da je to i dobro objašnjenje, teško varijabilno, čini ključnu razliku.
If the ancient Greeks had found out about seasons in Australia, they could have easily varied their myth to predict that. For instance, when Demeter's upset, she banishes heat from her vicinity into the other hemisphere, where it makes summer. So, being proved wrong by observation and changing their theory accordingly still wouldn't have got the ancient Greeks one jot closer to understanding seasons, because their explanation was bad -- easy to vary. And it's only when an explanation is good that it even matters whether it's testable. If the axis-tilt theory had been refuted, its defenders would have had nowhere to go. No easily implemented change could make that tilt cause the same seasons in both hemispheres.
Da su antički Grci saznali o godišnjim dobima u Australiji, mogli su lako prilagoditi svoj mit da to predvidi. Na primer, kada je Demetra uznemirena, ona protera vrućinu iz svoje blizine u drugu hemisferu, gde to stvara leto. I tako, opovrgavanje opažanjem, pa prigodno variranje teorije, ne bi još uvek antičke Grke ni za jotu približilo razumevanju godišnjih doba, jer je njihovo objašnjenje bilo loše: jednostavno za variranje. I samo onda kada je neko objašnjenje dobro je uopšte i bitno da li je proverljivo. Da je teorija o nagibu ose opovrgnuta, njeni proponenti ne bi imali gde. Nijedna jednostavno primenjena varijacija 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. It's the basic regulating principle of the Enlightenment. So, in science, two false approaches blight progress. One's well-known: untestable theories. But the more important one is explanationless theories. Whenever you're told that some existing statistical trend will continue but you aren't given a hard-to-vary account of what causes that trend, you're being told a wizard did it.
Potraga za teško promenljivim objašnjenjima je ishodište celokupnog napretka. To je osnovni regulatorni princip prosvetiteljstva. I tako, u nauci, dva pogrešna pristupa razaraju napredak. Jedan je dobro poznat: neproverljive teorije. Ali onaj važniji je - teorije bez objašnjenja. Kada god vam kažu da će se neki postojeći statistički trend nastaviti, ali vam nije dato i teško varijabilno objašnjenje o tome šta uzrokuje taj trend, govore vam da je to čarobnjak uradio.
When you are told that carrots have human rights because they share half our genes, but not how gene percentages confer rights -- wizard. When someone announces that the nature-nurture debate has been settled because there's evidence that a given percentage of our political opinions are genetically inherited, but they don't explain how genes cause opinions, they've settled nothing. They're saying that our opinions are caused by wizards, and presumably, so are their own.
Kada vam kažu da šargarepe imaju ljudska prava, jer dele polovinu naših gena - ali ne i kako procenti gena dodeljuju prava - čarobnjak. Kada neko objavi da je polemika urođeno-stečeno rešena jer postoje dokazi da je dati procenat naših političkih mišljenja genetski nasleđen, ali ne objašnjavaju kako geni prouzrokuju mišljenja, nisu rešili ništa. Oni govore da naša mišljenja prouzrokuju čarobnjaci, a pretpostavimo, i njihova sopstvena.
(Laughter)
Da se istina sastoji
That the truth consists of hard-to-vary assertions about reality is the most important fact about the physical world. It's a fact that is itself unseen, yet impossible to vary.
od teško varijabilnih tvrdnji o stvarnosti je najvažnija činjenica o fizičkom svetu. To je činjenica koja je i sama neviđena, a ipak, nemoguće je varirati je.
Thank you.
Hvala vam.
(Applause)
(Aplauz)