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Stephen Hawking

COPYRIGHT CANADIAN BROADCASTING CORPORATION

This is take 1. Starting June 20th. Interview with Professor Hawking.

WHEN DID YOU FIRST REALIZE THAT YOU WANTED TO BE A PHYSICIST?

I think I knew from about the age of 9 or 10 that I wanted to be a scientist. And probably from about the age of 15 that I wanted to be a physicist. Because I wanted to understand the basic problems of the universe. And try to understand how the universe works.

IS THIS AN ALL-CONSUMING KIND OF PASSION WITH YOU?

I don't quite know how you define that. Most of my activity is like playing with model fireworks, or model railways or model planes. Or playing complicated games. I was angling at some way of finding out how the world worked around me.

YOU WERE VERY BIG INTO MODELLING. IT'S CONTINUING.

I was never very good with my hands. So my models did not work very well. But I was always interested in models that I could control. Where I think that nowadays I have translated that into studying physics. Because in a way if you understand the universe, then you have control of it.

WHAT EXACTLY, LET'S BACK UP A LITTLE BIT OR LET'S START GETTING INTO PHYSICS, WHAT EXACTLY IS IT THAT A THEORETICAL PHYSICIST DOES?

What a theoretical physicist does is try to construct mathematical models which represent the universe. And which describe the results of observations. And we can say a model is a good model if it has few arbitrary elements, and if it describes all the observation so far made. And if it predicts the result of new observations correctly.

CAN YOU STOP FOR A SEC?

(cut tape)

Slate.

TRADITIONALLY, MUCH OF WHAT YOU SAY A PHYICIST DOES, TRY AND UNDERSTAND WHY THE UNIVERSE IS THE WAY THE UNIVERSE IS, HAS BEEN THE SUBJECT OF RELIGION, AND THERE HAVE OFTEN BEEN CONFLICTS BETWEEN ORGANIZED RELIGION AND THE CHURCH, GALILEOFOR INSTANCE, YOUR PREDECESSOR, 300 YEARS. 20TH CENTURY PHYSICS SEEMS TO HAVE MORE IN COMMON WITH MYSTICISM THAN MATERIALISM. WHAT ARE THE PRINCIPLE PHYSICAL IDEAS THAT HAVE OCCURRED IN THIS CENTURY THAT HAVE SHAPED THAT?

I don't think physics has much contact with mysticism. In fact it's really the very opposite of mysticism. Physics aims to find a rational model for the universe. And mysticism aims to describe the universe basically as a mystery. I think in a way physics has been a progress away from mysticism. Towards a rational understanding of the universe.

OKAY, BUT CERTAINLY IN THE 20TH CENTURY WHAT WE HAVE SEEN IS THE BREAKDOWN OF OUR COMMON EVERY DAY EXPERIENCE, AND OUR COMMON EVERY DAY WAY OF PERCEIVING THE WORLD TENDS TO BREAK DOWN IN MODERN PHYSICS. WHAT I'M GETTING AT IS TWO CENTRAL IDEAS WHICH HAVE OCCURRED IN THIS CENTURY OF RELATIVITY AND QUANTUM MECHANICS, BOTH OF WHICH COMMON SENSE APPROACH TO THE UNIVERSE IN THIS ORDINARY EVERYDAY EXPERIENCE TENDS TO BREAK DOWN COMPLETELY.

I think the whole history of human thought has been steady progress. In which old ideas are replaced by new ideas. You might say that common sense says that the world is flat. However, the ancient Greeks discovered that the world was round. And that must have been just as much of an upset to them as relativity and quantum mechanics are to us.

CAN YOU JUST PAUSE FOR A SECOND?...

(cut tape)

Slate.

Common sense tells us that the world is flat. However, the ancient Greeks discovered that the world was really round. That must have been as big an upset to them as the ideas of relativity and quantum mechanics are to us. Then up to the 15th century, after the 15th century common sense told people that the sun goes round the earth. But then they discovered that the earth really goes round the sun. And that gave rise to a big intellectual revolution. And up to this century we thought that space was flat. But then Einstein showed that one count account for gravity by saying that space time is really curved. And up to this century we thought that you could measure the position and velocity of a particle up to arbitrary accuracy. But then in this century we discovered a new kind of theory called quantum mechanics... which tells us that you cannot measure both the position and the velocity of a particle simultaneously to arbitrary accuracy. The more accurately you measure the position, the less accurately you know the velocity, and visa versa.

SO THIS INTRODUCES THE NOTION OF PROBABILITY INTO THE LAWS OF THE UNIVERSE?

Yes, because particles do not have a well defined position. They just have a probability distribution of being found in different places.

I UNDERSTAND THAT THIS UPSET ALBERT EINSTEIN VERY MUCH.

Einstein could not accept this element of probability or chance. He said that God does not play dice. But all the evidence we have suggests that there really is an element of randomness in the universe.

WHERE ELSE DOES COMMON SENSE BREAK DOWN TO THE LEVEL OF QUANTUM MECHANICS? I'M THINKING NOW OF PARTICLES APPEARING OUT OF NOTHING, WAVE PARTICLE DUALITIES, THINGS LIKE THAT.

What appears to be common sense is very much a function of time. In ancient times it was common sense to say the world was flat. And nowadays, if you were to ask a child, he would be able to tell you that you could travel in a spaceship to visit other planets and galaxies. But most people know rather little about quantum mechanics. Most people know very little about quantum mechanics, and therefore they find it appears to be contradictory to common sense. But maybe in the future when children are brought up in school with the idea of quantum mechanics, and they see it on television, they'll accept the ideas inherent in ...

THERE ARE MANY DIFFICULT IDEAS TO TAKE HOLD OF IN MODERN PHYSICS. ONE OF THEM IS THE NOTION OF A SINGULARITY. WHAT EXACTLY IS A SINGULARITY?

A singularity in space time is a place where the density of matter and the curvature of space time become infinite. And after singularity, the concepts of space and time break down.

SO WE CAN'T SAY ANYTHING ABOUT WHAT THE UNIVERSE IS LIKE...

Well, all the laws of physics are formulated in terms of space time, and therefore out of singularity they break down. In fact we cannot predict what will happen to the singularity.

THE COMMONLY ACCEPTED WAY THAT THE UNIVERSE BEGAN IS AS A SINGULARITY, WITH AN ENORMOUS EXPLOSION CALLED THE BIG BANG, AN ENORMOUS EXPANSION CALLED THE BIG BANG. ACCORDING TO WHAT YOU'RE SAYING THAT MEANS THAT WE REALLY CAN'T SAY ANYTHING ABOUT THE UNIVERSE AT THE POINT IT BEGAN. THIS MUST MAKE PEOPLE WHO BELIEVE IN DIVINE CREATION VERY HAPPY.

(cut tape)

Professor Hawking intv., 20Jun, tape 2.

Slate.

If Einstein's general theory of relativity is correct, the universe began with a singularity called the big bang. Now because it was a singularity, all the laws of physics broke down. And therefore we cannot predict how the universe began. A few years ago I was at a conference on cosmology that was held in the Vatican. And at the end of the conference the participants were granted an audience with the Pope. The Pope said it was fine for them to inquire into the early history of the universe, but they should not ask questions about the big bang itself... because that was the work of God. However, at that conference I proposed that Einstein's general theory of relativity would have to be modified to take quantum mechanics into account. And that modification would mean that there was no singularity. Space time would be finite in extent, but with no singularities. In this picture, space time would be like the surface of the earth. It's finite in extent, but it doesn't have any boundary or edge or singularities.

SO IT WOULDN'T BE POSSIBLE TO SAY THAT REALLY THAT THE UNIVERSE HAS A BEGINNING OR END, OR WHAT WOULD BE POSSIBLE TO SAY ABOUT BEGINNING AND CAUSATION?

The universe... the universe would have a beginning and an end in the same sense that degrees of latitude have a beginning and an end at the north and south poles respectively. There isn't any point with a latitude 91 degrees north. And similarly, there isn't any point in the universe which is before the big bang. And the, but the north pole is a perfectly regular point of the earth's surface, it's not a singular point. And similarly, I believe that the big bang was a perfectly regular point of space time. And all the laws of physics would hold at the big bang. And if that is the case, we can completely predict the state of the universe from the laws of physics.

SO WHAT CAN YOU SAY ABOUT, ...ESSENTIALLY MEANS THAT THE UNIVERSE, YOU CANNOT SAY THAT THE UNIVERSE IS CAUSED, RIGHT? IS THAT CORRECT?

That's right. The universe does not have any beginning or end. It does not have any cause or consequence. It simply is.

YOU HAVE PUT THIS OUT AS UNDER THE WORD PROPOSAL, AND NOT THEORY. WHAT IS THE DIFFERENCE?

There isn't really any difference. There isn't really any difference. Every theory is really proposal. You can't deduce a new theory. You have to make a new proposal. What you do is, you make a new proposal and calculate the consequences. And if they agree with observations then you call it a new theory.

THE CONSEQUENCES OF A THEORY WHICH SAYS THAT THE UNIVERSE IS NOT CAUSED ARE FAR GREATER PROBABLY IN THE REALM OF PHILOSOPHY AND RELIGION THAN THEY ARE IN THE REALM OF PHYSICS. LET'S LEAVE THE QUESTION OF THE PHILOSOPHERS AND THE RELIGIONISTS ASIDE FOR A SECOND. WHAT HAS THE REACTION BEEN TO THE REST OF THE WORLD OF PHYSICISTS? HOW HAVE THEY REACTED TO A CAUSELESS UNIVERSE? AN UNCAUSED UNIVERSE?

I think that most of those who believe my proposal... sorry. I think that most of those who have heard my proposal and understand it, believe it's a possibility. And insofar as it doesn't lead to contradictionist observations, it may be correct.

(cut tape)

Slate.

Most people who understand my proposal believe that it is a possibility. But I think that most of them would reserve judgment as to whether it is correct. But I don't think that anybody believes it is definitely wrong.

WHAT ABOUT THE PHILOSOPHICAL IMPLICATIONS OF WHAT YOU'RE PROPOSING? DOESN'T IT REQUIRE US TO FORM A COMPLETELY DIFFERENT CONCEPTION OF HUMANKIND AND HUMANKIND'S RELATIONSHIP TO A SUPREME DIETY?

Well, most scientists don't like to think too much about philosophical questions. They feel that such questions are really badly defined. And they'd rather stick to questions that they understand.

NEVERTHELESS, THE HISTORY OF DISCOVERIES MADE IN SCIENCE, BOTH THEORETICAL AND PRACTICAL, ARE CONSTANTLY ALTERING THE PREVAILING WORLD VIEW.

That is certainly true, but many scientists feel if they start talking about such questions, they'll be regarded as cranks rather than as serious scientists.

I DON'T KNOW, EINSTEIN SHOULD HAVE KEPT HIS MOUTH SHUT AND NOT SAID ANYTHING ABOUT... OKAY. YOU CARE NOT TO SPECULATE ABOUT WHAT THE PHILOSOPHICAL...

I think that there are important philsophical implications, and that scientists really should think about them. But what I'm saying is that I think most scientists are just rather reluctant to talk about such questions.

THAT MEANS INCLUDING YOU NOW, RIGHT?

No, not including me.

OKAY, SO WHAT KIND OF IMPLICATIONS ARE WE TALKING ABOUT?

Obviously implications about the existence and the nature of God. Is there a God who intervenes in the universe, or one who wound up the clock to set things going? I think with the progress of science, most scientists now believe that God does not intervene in the universe. And they believe that the universe evolves according to laws of science. And that there aren't any exceptions to these laws. But I think that most scientists still reserve judgment on how the universe was set up in the first place. Whether that was an act of God, or whether that too was subject to the laws of science. What I'm suggest is, that it was indeed subject to the laws of science.

WHEN I ASKED THE QUESTION, HOWEVER, I SAID DOES IT NOT REQUIRE A RADICAL RELOOKING AT THE WHOLE RELATIONSHIP BETWEEN WHAT WE CONSIDER A DIVINE BEING, AND OURSELVES? SOME PEOPLE ARE PROPOSING THAT AN EASTERN CONCEPT, OR A CONCEPT BORROWED FROM EASTERN PHILOSOPHY MIGHT SOLVE THE PROBLEM IN THAT THERE DOES NOT HAVE TO BE A CAUSAL RELATIONSHIP BETWEEN SPACE TIME, AND WHAT IS NOT SPACE TIME. THE TWO THINGS SIMPLY ARE.

My opinion is that such ideas don't really explain anything. They merely shroud everything in obscurity.

ALL OF THEORETICAL PHYSICS SEEMS TO BE DIRECTED TOWARDS THE EVENTUAL GOAL, THAT'S A UNIFIED FIELD THEORY, AN UNDERSTANDING ONF FUNDAMENTAL LAWS THAT UNIFY ALL OF NATURE, INCLUDING MANKIND. WILL WE EVER FIND SUCH A THEORY, AND IF SO, WHAT COULD BE THE CONSEQUENCES?

I think it's an open question as to whether we will find a complete unified theory. All I can say is that we don't seem to have one at the moment.

*END

SLATE

YOU WERE SAYING THAT THERE MAYBE SUCH A THING . . .

We may never find a complete unified theory, but I think that there is a 50-50 chance that we'll do so by the end of the century.

WHAT WOULD BE THE CONSEQUENCES OF SUCH A THEORY? WOULD WE THEN KNOW EVERYTHING THERE IS TO KNOW ABOUT PHYSICAL REALITY?

In principle, but not in practice. Because the equations are very difficult to solve in any but the simplest situations. We already know the laws of physics that underlie the behaviour of matter in normal circumstances. So in principle, we should be able to predict all of physics, all of chemistry and biology. But we've not had much success in predicting human behaviour from mathematical equations.

SO LIFE WILL STILL BE FULL OF SURPRISES?

Yes, in principle we should be able to predict everything. But in practice it won't make any difference. We already know the laws of physics which govern this matter except in circumstances as extreme as the beginning of the early stages of the universe.

YOU LIVE IN A WORLD THAT APPEARS TO BE VERY ESOTERIC AND DISTANT AND ABSTRACT FROM THE ORDINARY MAN-IN-THE-STREET, EVEN TO YOUR WIFE. DO YOU EVER GET FRUSTRATED BY THE DIFFICULTIES IN COMMUNICATING THE NATURE OF YOUR WORK?

I believe most people have an interest in how the universe works, even though they may not have much technical knowledge. But I think in principle it should be easy to explain the basic ideas.

HOW ABOUT IN PRACTICE, DOES IT EVER FRUSTRATE YOU?

I do my best, and I do think I have some success.

YOU ARE QUITE ACTIVE ON BEHALF OF DISABLED PEOPLE IN OBTAINING GRANTS. WHAT ATTITUDE DO YOU TAKE TO YOUR OWN DISABILITY?

It is a bit of an inconvenience. But it has not really prevented me from doing what I want to do in life. In a way, it has made me appreciate much more . . . I've been much fortunate in being able to carry on. And that is really due to all the help that I've had from my family and colleagues.

HAD YOU NOT BEEN DISABLED, WOULD YOU HAVE BEEN INVOLVED IN THE SAME BRANCH OF PHYSICS?

If I had not been disabled, then certain things would have been easier. Like reading books or writing down equations. But on the other hand, I would have had to spend more time lecturing and setting examinations. So, all in all, I don't think it has made much difference to the amount of work that I would have been able to do. If it has had any effect at all, it has probably affected the kind of work I do. Because I think I'd probably have worked with problems involving a lot of equations. And if I had not been disabled, I might have done a lot more work in problems which required a great deal of equations.

YOU SAID THAT WHEN YOU FIRST FOUND OUT YOU HAD YOUR DISEASE IT WAS VERY DIFFICULT, THAT YOU BECAME QUITE FULL OF DESPAIR AND QUITE BITTER. COULD YOU TELL ME A LITTLE BIT ABOUT THAT PERIOD?

I don't think I became bitter. But I was certainly depressed. I didn't at the time think there was much point in completing my Ph.D. because my life expectency was so short.

HOW DID IT CHANGE FOR YOU?

SLATE

The disease progressed rapidly at first. But then it seemed to slow down. And around the same time I began to fully understand the problem I was working on. But what really made a difference was that I became engaged to Jane. That meant that if I was going to get married, I'd have to get a job. And if I was going to get a job, I'd have to write some papers. So that really started me working. And I've been at it every since.

BECAUSE OF YOUR ILLNESS, ARE YOU IN A RACE AGAINST TIME?

Not really, in a sense all theoretical physicists are in a race against time. Because as they get older, it's rather harder to do theoretical physics. My supervisor, Dennis Yama, had a party when he was 30 to celebrate his retirement as a theoretical physicist. But in fact his best work came after that.

JUST GOES TO SHOW YOU . . .

I'm now 43, and generally considered a bit overhill for a theoretical physicist.

YOU SEEM TO BE HOLDING UP OKAY. YOUR SCIENCE IS MORALLY NEUTRAL. WHAT ISSUES SHOULD SCIENTISTS TODAY BE SPEAKING OUT ABOUT?

I think that science itself is morally neutral. But scientists themselves need not be morally neutral. They are human beings like everyone else. They have moral responsibilities.

WHAT ISSUES THEN SHOULD SCIENTISTS BE TALKING ABOUT?

All issues, but particularly those like nuclear warfare. Which involve a complicated set of equations. I think questions such as nuclear war, which involve an awful lot of complicated questions which most people cannot judge for themselves.

...HAVE WRITTEN ABOUT YOU IN WAYS THAT ALMOST IMPLIES YOU'RE LIKE A COMPLETE CERBO BEING. THAT YOU DON'T HAVE AN EMOTIONAL LIFE . . .

That is completely untrue. I don't live for science alone. Science is very important to me, but it is not enough. In fact if that's all I had, then my life would be very empty. I'm very lucky that I have my family. They are very important to me.

ARE THEY A SOURCE OF JOY?

Oh yes.

CUT FOR SYNCH