Thank you for putting up these pictures of my colleagues over here. (Laughter) We'll be talking about them. Now, I'm going try an experiment. I don't do experiments, normally. I'm a theorist. But I'm going see what happens if I press this button. Sure enough. OK. I used to work in this field of elementary particles. What happens to matter if you chop it up very fine? What is it made of? And the laws of these particles are valid throughout the universe, and they're very much connected with the history of the universe.
Hvala što ste postavili slike mojih kolega ovdje. (Smijeh) Pričat ćemo o njima. Pokušat ću izvesti jedan eksperiment. Inače ne eksperimentiram, ja sam teoretičar. Ali zanima me što će se dogoditi ako pritisnem ovo dugme. Sigurno. OK. Nekad sam radio u ovom području elementarnih čestica. Što se događa s materijom ako je fino nasjeckate? Od čega se sastoji? A zakoni tih čestica vrijede širom svemira, i uvelike su povezani s njegovom poviješću.
We know a lot about four forces. There must be a lot more, but those are at very, very small distances, and we haven't really interacted with them very much yet. The main thing I want to talk about is this: that we have this remarkable experience in this field of fundamental physics that beauty is a very successful criterion for choosing the right theory. And why on earth could that be so?
Znamo mnogo o četiri sile. Mora ih biti puno više, ali su na vrlo, vrlo malim udaljenostima, i još zapravo nismo ostvarivali puno interakcije s njima. Glavno o čemu želim govoriti je sljedeće: da na polju fundamentalne fizike imamo izuzetno iskustvo koje govori kako je ljepota uspješan kriterij za odabir prave teorije. Kako to, pobogu, može biti?
Well, here's an example from my own experience. It's fairly dramatic, actually, to have this happen. Three or four of us, in 1957, put forward a partially complete theory of one of these forces, this weak force. And it was in disagreement with seven -- seven, count them, seven experiments. Experiments were all wrong.
Evo primjera iz mojeg osobnog iskustva. Prilično je dramatično, u stvari, kada se ovo dogodi. Nas trojica ili četvorica, godine 1957., predložili smo djelomičnu teoriju jedne od tih sila, slabe sile. Ona nije bila u skladu sa sedam – sedam, izbrojte, sedam eksperimenata. Svi su eksperimenti bili pogrešni.
And we published before knowing that, because we figured it was so beautiful, it's gotta be right! The experiments had to be wrong, and they were. Now our friend over there, Albert Einstein, used to pay very little attention when people said, "You know, there's a man with an experiment that seems to disagree with special relativity. DC Miller. What about that?" And he would say, "Aw, that'll go away." (Laughter)
Objavili smo teoriju prije nego što smo to znali, jer smo mislili da ako je tako lijepa, mora biti točna! Eksperimenti su morali biti u krivu, i bili su. Naš prijatelj ondje, Albert Einstein, nije obraćao puno pažnje kad bi ljudi rekli, "Znate, imate čovjeka čiji eksperiment se izgleda ne slaže sa specijalnom relativnošću. DC Miller. Što mislite o tome?" A on bi rekao, "O, to će proći." (Smijeh)
Now, why does stuff like that work? That's the question. Now, yeah, what do we mean by beautiful? That's one thing. I'll try to make that clear -- partially clear. Why should it work, and is this something to do with human beings? I'll let you in on the answer to the last one that I offer, and that is, it has nothing to do with human beings. Somewhere in some other planet, orbiting some very distant star, maybe in a another galaxy, there could well be entities that are at least as intelligent as we are, and are interested in science. It's not impossible; I think there probably are lots.
Zašto su takve stvari moguće? To je pitanje. Sad, što smatramo lijepim? To je jedno. Nastojat ću to razjasniti – djelomično razjasniti. Zašto je tako, ima li to veze s ljudskim bićima? Odgovorit ću vam na posljednje pitanje, a odgovor je nema, nema veze s ljudima. Negdje, na nekom drugom planetu, u orbiti oko daleke zvijezde, možda u drugoj galaksiji, mogla bi postojati bića koja su inteligentna barem koliko i mi, i koje zanima znanost. Nije nemoguće; mislim da ih je mnogo.
Very likely, none is close enough to interact with us. But they could be out there, very easily. And suppose they have, you know, very different sensory apparatus, and so on. They have seven tentacles, and they have 14 little funny-looking compound eyes, and a brain shaped like a pretzel. Would they really have different laws? There are lots of people who believe that, and I think it is utter baloney. I think there are laws out there, and we of course don't understand them at any given time very well -- but we try. And we try to get closer and closer.
Vjerojatno nitko od njih nije dovoljno blizu da stupi u kontakt s nama. Ali lako bi mogli biti ondje. Pretpostavimo da imaju sasvim različit skup osjetila. Imaju sedam ticala, 14 malenih složenih očiju smiješnog izgleda, i mozak u obliku pereca. Da li bi oni zaista imali drugačije zakone? Mnogi ljudi u to vjeruju, a ja mislim da je to glupost. Mislim kako postoje zakoni, i mi ih, naravno, ne shvaćamo dobro u bilo koje doba -- ali se trudimo. I trudimo se doći sve bliže i bliže.
And someday, we may actually figure out the fundamental unified theory of the particles and forces, what I call the "fundamental law." We may not even be terribly far from it. But even if we don't run across it in our lifetimes, we can still think there is one out there, and we're just trying to get closer and closer to it. I think that's the main point to be made. We express these things mathematically. And when the mathematics is very simple -- when in terms of some mathematical notation, you can write the theory in a very brief space, without a lot of complication -- that's essentially what we mean by beauty or elegance.
Jednoga dana, mogli bismo otkriti fundamentalnu objedinjujuću teoriju čestica i sila, koju nazivam "fundamentalnim zakonom". Možda nismo ni tako daleko od tog otkrića. Ali čak i ako ne dođemo do njega u našem životnom vijeku, ipak možemo smatrati da ono postoji, i naprosto mu se pokušavamo što više približiti. Mislim kako je to ono što je najvažnije istaknuti. Mi to izražavamo matematički. A kada je matematika vrlo jednostavna -- kad, u smislu neke matematičke notacije, možete napisati teoriju koja je kratka, bez mnogo komplikacija -- to je, u suštini, ono što smatramo ljepotom ili elegancijom.
Here's what I was saying about the laws. They're really there. Newton certainly believed that. And he said, here, "It is the business of natural philosophy to find out those laws." The basic law, let's say -- here's an assumption. The assumption is that the basic law really takes the form of a unified theory of all the particles. Now, some people call that a theory of everything. That's wrong because the theory is quantum mechanical. And I won't go into a lot of stuff about quantum mechanics and what it's like, and so on. You've heard a lot of wrong things about it anyway. (Laughter) There are even movies about it with a lot of wrong stuff.
Eto što sam govorio o zakonima. Oni stvarno postoje. Newton je svakako u to vjerovao. Rekao je, "Zadaća je filozofije prirode otkriti te zakone." Temeljni zakon, recimo – evo pretpostavke. Pretpostavka je da temeljni zakon ima oblik objedinjavajuće teorije svih čestica. Neki ljudi to nazivaju teorijom svega. To je pogrešno jer je teorija kvantno-mehanička. Neću ulaziti duboko u kvantnu mehaniku i njezina svojstva. Ionako ste čuli puno toga pogrešnog o njoj. (Smijeh) Imate čak i filmove o njoj s puno pogrešaka.
But the main thing here is that it predicts probabilities. Now, sometimes those probabilities are near certainties. And in a lot of familiar cases, they of course are. But other times they're not, and you have only probabilities for different outcomes. So what that means is that the history of the universe is not determined just by the fundamental law. It's the fundamental law and this incredibly long series of accidents, or chance outcomes, that are there in addition.
Ali najvažnija stvar je da ona predviđa vjerojatnosti. Te su vjerojatnosti ponekad skoro izvjesnosti. I u mnogim poznatim slučajevima, naravno da jesu. Ali u drugim slučajevima nisu, i imate samo vjerojatnosti različitih ishoda. Pa se čini kako povijest svemira nije uvjetovana jedino fundamentalnim zakonom. Tu su fundamentalni zakon i nevjerojatno dug niz slučajnosti, slučajnih ishoda, koji također postoje.
And the fundamental theory doesn't include those chance outcomes; they are in addition. So it's not a theory of everything. And in fact, a huge amount of the information in the universe around us comes from those accidents, and not just from the fundamental laws. Now, it's often said that getting closer and closer to the fundamental laws by examining phenomena at low energies, and then higher energies, and then higher energies, or short distances, and then shorter distances, and then still shorter distances, and so on, is like peeling the skin of an onion. And we keep doing that, and build more powerful machines, accelerators for particles. We look deeper and deeper into the structure of particles, and in that way we get probably closer and closer to this fundamental law.
A fundamentalna teorija ne uključuje te slučajne ishode; oni su dodatak. Zato to nije teorija svega. Zapravo, ogromna količina informacija u svemiru nastaje iz tih slučaja, a ne samo iz fundamentalnih zakona. Često se tvrdi da približavanje fundamentalnim zakonima putem ispitivanja fenomena pri niskim, a zatim i visokim energijama, pa još višim energijama, na kratkim udaljenostima, pa još kraćim, pa još kraćim, da je to poput ljuštenja luka. Mi to činimo i gradimo sve moćnije uređaje, akceleratore čestica. Poniremo sve dublje i dublje u strukturu čestica, i na taj se način vjerojatno približavamo fundamentalnom zakonu.
Now, what happens is that as we do that, as we peel these skins of the onion, and we get closer and closer to the underlying law, we see that each skin has something in common with the previous one, and with the next one. We write them out mathematically, and we see they use very similar mathematics. They require very similar mathematics. That is absolutely remarkable, and that is a central feature of what I'm trying to say today. Newton called it -- that's Newton, by the way -- that one.
No, dok ljuštimo taj luk i dolazimo sve bliže i bliže temeljnom zakonu, vidimo da svaka ljuska ima nešto zajedničko s prethodnom, a i sa narednom. Ispisujemo to matematički i vidimo da koriste sličnu matematiku. To zahtijeva sasvim sličnu matematiku. To je apsolutno fenomenalno, i ono najvažnije što vam pokušavam danas reći. Newton je to nazvao – ovo je Newton, usput -- onaj.
This one is Albert Einstein. Hi, Al! And anyway, he said, "nature conformable to herself" -- personifying nature as a female. And so what happens is that the new phenomena, the new skins, the inner skins of the slightly smaller skins of the onion that we get to, resemble the slightly larger ones. And the kind of mathematics that we had for the previous skin is almost the same as what we need for the next skin. And that's why the equations look so simple. Because they use mathematics we already have.
Ovo je Albert Einstein. Pozdrav, Al! Kakobilo rekao je, "Priroda je u skladu sa samom sobom" – personificirajući prirodu kao ženu. Dakle, događa se da novi fenomeni, nove ljuske, unutarnje ljuske manjih ljuski luka do kojih dopiremo, sliče na malo veće ljuske. I matematika koja nam treba za prethodnu ljusku je skoro ista kao ona koju trebamo za sljedeću. I zato jednadžbe izgledaju tako jednostavne. Jer koriste matematiku koju već imamo.
A trivial example is this: Newton found the law of gravity, which goes like one over the square of the distance between the things gravitated. Coulomb, in France, found the same law for electric charges. Here's an example of this similarity. You look at gravity, you see a certain law. Then you look at electricity. Sure enough. The same rule. It's a very simple example. There are lots of more sophisticated examples. Symmetry is very important in this discussion. You know what it means. A circle, for example, is symmetric under rotations about the center of the circle. You rotate around the center of the circle, the circle remains unchanged. You take a sphere, in three dimensions, you rotate around the center of the sphere, and all those rotations leave the sphere alone. They are symmetries of the sphere. So we say, in general, that there's a symmetry under certain operations if those operations leave the phenomenon, or its description, unchanged.
Evo trivijalnog primjera: Newton je otkrio zakon gravitacije, koji glasi jedan nad kvadratom udaljenosti između gravitiranih subjekata. Coulomb, u Francuskoj, otkrio je da isti zakon vrijedi za električne naboje. Evo primjera te sličnosti. Gledate gravitaciju, vidite određeni zakon. Zatim gledate elekticitet. Sigurno. Isto pravilo. To je vrlo jednostavan primjer. Ima mnogo profinjenijih primjera. Simetrija je vrlo važna za ovu diskusiju. Znate što to znači. Krug, na primjer, je simetričan po rotacijama oko središta kruga. Rotirate oko središta kruga i krug ostaje nepromijenjen. Uzmite kuglu. U tri dimenzije rotirate oko središta, i sve te rotacije ne mijenjaju kuglu. To su simetrije kugle. Pa kažemo, općenito, da postoji simetrija u okviru određenih postupaka ako ti postupci, ne mijenjaju fenomen ili njegov opis.
Maxwell's equations are of course symmetrical under rotations of all of space. Doesn't matter if we turn the whole of space around by some angle, it doesn't leave the -- doesn't change the phenomenon of electricity or magnetism. There's a new notation in the 19th century that expressed this, and if you use that notation, the equations get a lot simpler. Then Einstein, with his special theory of relativity, looked at a whole set of symmetries of Maxwell's equations, which are called special relativity. And those symmetries, then, make the equations even shorter, and even prettier, therefore.
Maxwellove jednadžbe su simetrične u rotacijama svega prostora. Nije važno okrećemo li cijeli prostor pod nekim kutom, to ne mijenja fenomen elektriciteta ili magnetizma. U 19. stoljeću se pojavljuje nova notacija koja to iskazuje i ako koristite tu notaciju, jednadžbe postaju puno jednostavnije. Pa Einstein, koji je, sa svojom specijalnom teorijom relativnosti, promotrio cijeli skup simetrija Maxwellovih jednadžbi, koje zovemo specijalna relativnost. I te simetrije su još skratile jednadžbe i učinile ih ljepšima nego ranije.
Let's look. You don't have to know what these things mean, doesn't make any difference. But you can just look at the form. (Laughter) You can look at the form. You see above, at the top, a long list of equations with three components for the three directions of space: x, y and z. Then, using vector analysis, you use rotational symmetry, and you get this next set. Then you use the symmetry of special relativity and you get an even simpler set down here, showing that symmetry exhibits better and better. The more and more symmetry you have, the better you exhibit the simplicity and elegance of the theory.
Pogledajmo. Ne morate znati što ovo znači, uopće nije važno. Ali gledajte samo oblik. (Smijeh) Možete gledati oblik. Vidite gore, na vrhu, dugi popis jednadžbi s tri komponente za tri prostorna smjera: x, y i z. Zatim, pomoću vektorske analize, koristite rotacijsku simetriju i dobijete sljedeći skup. Zatim koristite simetriju specijalne relativnosti i dobijete jednostavniji skup ovdje dolje, što pokazuje da se simetrija vidi sve bolje. Što više simetrije imate, to bolje pokazujete jednostavnost i eleganciju teorije.
The last two, the first equation says that electric charges and currents give rise to all the electric and magnetic fields. The next -- second -- equation says that there is no magnetism other than that. The only magnetism comes from electric charges and currents. Someday we may find some slight hole in that argument. But for the moment, that's the case.
Posljednje dvije, prva jednadžba kaže da električni naboj i struja povećavaju sva električna i magnetna polja. Sljedeća – druga – kaže kako nema drugog magnetizma osim toga. Jedini magnetizam dolazi od električnog naboja i struje. Jednoga dana ćemo možda pronaći rupicu u tom argumentu. Ali, trenutno, to je tako.
Now, here is a very exciting development that many people have not heard of. They should have heard of it, but it's a little tricky to explain in technical detail, so I won't do it. I'll just mention it. (Laughter) But Chen Ning Yang, called by us "Frank" Yang -- (Laughter) -- and Bob Mills put forward, 50 years ago, this generalization of Maxwell's equations, with a new symmetry. A whole new symmetry. Mathematics very similar, but there was a whole new symmetry. They hoped that this would contribute somehow to particle physics -- didn't. It didn't, by itself, contribute to particle physics.
Evo jednog vrlo uzbudljivog otkrića za koje mnogi nisu čuli. Trebali su čuti za to, ali malo je zeznuto objasniti tehničke detalje, pa neću ni ja. Samo ću vam spomenuti. (Smijeh) Ali Chen Ning Yang, koga mi zovemo "Frank" Yang -- (Smijeh) -- i Bob Mills su to predložili, prije 50 godina, uopćavanje Maxwellovih jednadžbi, s novom simetrijom. Cijelom novom simetrijom. Matematika je vrlo slična, ali s cijelom novom simetrijom. Nadali su se da će to nekako doprinijeti fizici čestica -- ali nije. Sama po sebi, nije doprinijela fizici čestica.
But then some of us generalized it further. And then it did! And it gave a very beautiful description of the strong force and of the weak force. So here we say, again, what we said before: that each skin of the onion shows a similarity to the adjoining skins. So the mathematics for the adjoining skins is very similar to what we need for the new one. And therefore it looks beautiful because we already know how to write it in a lovely, concise way.
A zatim su to neki od nas još poopćili. I tada je doprinijelo! I dalo prelijep opis jake sile i slabe sile. Pa opet kažemo, što smo već rekli: da svaka ljuska luka pokazuje sličnost sa susjednom ljuskom. Pa je matematika susjednih ljuski slična onoj kakvu trebamo za novu ljusku. I zato to izgleda lijepo, jer već znamo kako je napisati na lijep, sažet način.
So here are the themes. We believe there is a unified theory underlying all the regularities. Steps toward unification exhibit the simplicity. Symmetry exhibits the simplicity. And then there is self-similarity across the scales -- in other words, from one skin of the onion to another one. Proximate self-similarity. And that accounts for this phenomenon. That will account for why beauty is a successful criterion for selecting the right theory.
Ovo su teme. Vjerujemo da postoji jedinstvena teorija u podlozi svih regularnosti. Koraci prema objedinjavanju iskazuju jednostavnost. Simetrija iskazuje jednostavnost. A postoji i međusobna sličnost na svim razinama – drugim riječima, od jedne ljuske luka do druge. Približna međusobna sličnost. A to objašnjava ovaj fenomen. To objašnjava zašto je ljepota uspješan kriterij za odabir prave teorije.
Here's what Newton himself said: "Nature is very consonant and conformable to her self." One thing he was thinking of is something that most of us take for granted today, but in his day it wasn't taken for granted. There's the story, which is not absolutely certain to be right, but a lot of people told it. Four sources told it. That when they had the plague in Cambridge, and he went down to his mother's farm -- because the university was closed -- he saw an apple fall from a tree, or on his head or something. And he realized suddenly that the force that drew the apple down to the earth could be the same as the force regulating the motions of the planets and the moon.
Evo što je Newton rekao: "Priroda je harmonična i u skladu sama sa sobom." On je razmišljao o nečemu što većina nas danas uzima zdravo za gotovo, ali u njegovo doba se nije uzimalo zdravo za gotovo. Ima priča, za koju nije sasvim sigurno da je istinita, ali se puno puta prepričavala. Četiri izvora ju je pričalo. U vrijeme kuge u Cambridgeu, kad je otišao na majčinu farmu – jer je sveučilište zatvoreno -- vidio je kako jabuka pada sa stabla, ili mu je pala na glavu. I iznenada je shvatio da bi sila koja je povukla jabuku prema zemlji mogla biti ista ona sila koja upravlja kretanjem planeta i Mjeseca.
That was a big unification for those days, although today we take it for granted. It's the same theory of gravity. So he said that this principle of nature, consonance: "This principle of nature being very remote from the conceptions of philosophers, I forbore to describe it in that book, lest I should be accounted an extravagant freak ... " That's what we all have to watch out for, (Laughter) especially at this meeting. " ... and so prejudice my readers against all those things which were the main design of the book."
To je bila objedinjujuća teorija onih dana, premda je danas uzimamo zdravo za gotovo. To je ta teorija gravitacije. Pa je rekao za taj prirodni princip, harmoniju: "Taj je prirodni princip jako daleko od filozofskih koncepata, i suzdržavam se da ga opišem u knjizi, da ne bih bio smatran ekstravagantnom nakazom ... " Svi se mi moramo toga čuvati, (Smijeh) naročito na ovom skupu. " ... i izazvao predrasude u čitatelja protiv svih teza koje su temelj ove knjige."
Now, who today would claim that as a mere conceit of the human mind? That the force that causes the apple to fall to the ground is the same force that causes the planets and the moon to move around, and so on? Everybody knows that. It's a property of gravitation. It's not something in the human mind. The human mind can, of course, appreciate it and enjoy it, use it, but it's not -- it doesn't stem from the human mind. It stems from the character of gravity. And that's true of all the things we're talking about. They are properties of the fundamental law. The fundamental law is such that the different skins of the onion resemble one another, and therefore the math for one skin allows you to express beautifully and simply the phenomenon of the next skin.
Tko bi danas tvrdio da je to izmišljotina ljudskog uma? Da je sila uslijed koje jabuka pada na tlo ista ona sila koja vodi kretanje planeta i Mjeseca? Svi to znaju. To je svojstvo gravitacije. Ta ideja nije u ljudskom umu. Ljudski um je, naravno, može cijeniti i uživati u njoj, rabiti je, ali ona nije samo plod ljudskog uma. Ona proistječe iz svojstava gravitacije. Isto vrijedi za sve o čemu pričamo. Sve su to svojstva fundamentalnog zakona. Fundamentalni zakon je takav da različite ljuske luka sliče jedna na drugu, i zato vam matematika jedne ljuske omogućava da lijepo i jednostavno objasnite fenomen sljedeće ljuske.
I say here that Newton did a lot of things that year: gravity, the laws of motion, the calculus, white light composed of all the colors of the rainbow. And he could have written quite an essay on "What I Did Over My Summer Vacation." (Laughter) So we don't have to assume these principles as separate metaphysical postulates. They follow from the fundamental theory. They are what we call emergent properties. You don't need -- you don't need something more to get something more. That's what emergence means.
Newton je otkrio puno stvari te godine: gravitaciju, zakone gibanja, račun, da se bijela svjetlost sastoji od duginih boja. I mogao je napisati popriličan esej na temu "Što sam radio tijekom ljetnih ferija.“ (Smijeh) Znači, ne moramo tretirati te principe kao zasebne metafizičke postulate. Oni proistječu iz fundamentalne teorije. Oni su ono što nazivamo pojavna svojstva. Ne trebate nešto više da biste dobili nešto više. To je ono što pojavnost znači.
Life can emerge from physics and chemistry, plus a lot of accidents. The human mind can arise from neurobiology and a lot of accidents, the way the chemical bond arises from physics and certain accidents. It doesn't diminish the importance of these subjects to know that they follow from more fundamental things, plus accidents. That's a general rule, and it's critically important to realize that. You don't need something more in order to get something more. People keep asking that when they read my book, "The Quark and the Jaguar," and they say, "Isn't there something more beyond what you have there?" Presumably, they mean something supernatural. Anyway, there isn't. (Laughter) You don't need something more to explain something more. Thank you very much. (Applause)
Život se može pojaviti iz fizike i kemije, plus mnogo slučajnosti. Ljudski um može nastati iz neurobiologije i mnogih slučajnosti, isto kao što se kemijske veze rađaju iz fizike i određenih slučajnosti. Važnost tih stvari ne umanjuje spoznaja da proistječu iz fundamentalnijih stvari, plus slučaja. To je opće pravilo i kritično je važno to shvatiti. Ne trebate nešto više da biste dobili nešto više. Ljudi uvijek pitaju čitajući moju knjigu, "Kvark i jaguar," "Ne postoji li i nešto povrh ovoga što spominjete ovdje?" Za pretpostaviti je da misle na nešto nadnaravno. Bilo kako bilo, ne postoji. (Smijeh) Ne treba vam nešto više da biste objasnili nešto više. Hvala vam lijepa. (Pljesak)