Quotes by Stephen Hawking

Quantum physics tells us that no matter how thorough our observation of the present, the (unobserved) past, like the future, is indefinite and exists only as a spectrum of possibilities.

If aliens ever visit us, I think the outcome would be much as Christopher Columbus first landed in America, which didn't turn out very well for the Native Americans.

Considering the number of planets and stars that we know exist, it's extremely unlikely that we are the only form of evolved life.

We are all now connected by the internet, like neurons in a giant brain.

However bad life may seem, there is always something you can do and succeed at. Where there's life, there's hope.

Teamwork means never having to take all the blame yourself.

By 2600, the world population would be standing shoulder to shoulder and the electricity consumed would make the earth glow red-hot.

Before we understand science, it is natural to believe that God created the universe.

I have found far greater enthusiasm for science in America than here in Britain. There is more enthusiasm for everything in America.

There is nothing bigger or older than the universe.

I'm an atheist.

I believe there are no questions that science can't answer about a physical universe.

I want my books sold on airport bookstalls.

I'm never any good in the morning. It is only after four in the afternoon that I get going.

Although quantum mechanics has been around for nearly 70 years, it is still not generally understood or appreciated, even by those that use it to do calculations.

Children in backseats cause accidents. Accidents in backseats cause children.

I like physics, but I love cartoons.

A theory is a good theory if it satisfies two requirements: it must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations.

Disability need not be an obstacle to success.

So some might imagine that I am an expert on time, although of course these days an expert is not necessarily a good thing to be.

The increase of disorder or entropy with time is one example of what is called an arrow of time, something that distinguishes the past from the future, giving a direction to time.

Only a very few would allow creatures like us to exist. Thus our presence selects out from this vast array only those universes that are compatible with our existence. Although we are puny and insignificant on the scale of the cosmos, this makes us in a sense the lords of creation.

Never put off the work till tomorrow what you can put off today.

The wise never marry, and when they marry they become otherwise.

One is always a long way from solving a problem until one actually has the answer.

When I hear of Schrödinger's cat, I reach for my pistol.

We think that life develops spontaneously on Earth, so it must be possible for life to develop on suitable planets elsewhere in the universe. But we don't know the probability that a planet develops life.

It is reasonable to ask who or what created the universe, but if the answer is God, then the question has merely been deflected to that of who created God.

Half the battle is just showing up.

Science makes God unnecessary.

The Simpsons is the best thing on American television.

A society in which the individual feels responsible for his or her actions is more likely to work together and survive to spread its values.

I think the next century will be the century of complexity.

Equations are just the boring part of mathematics. I attempt to see things in terms of geometry.

I first had the idea of writing a popular book about the universe in 1982. My intention was partly to earn money to pay my daughter's school fees.

One could imagine such technology outsmarting financial markets, out-inventing human researchers, out-manipulating human leaders, and developing weapons we cannot even understand.

Maybe my variety is due to bad absorption of vitamins.

To my mathematical brain, the numbers alone make thinking about aliens perfectly rational.

If the government is covering up knowledge of aliens, they are doing a better job of it than they do at anything else.

The question is: is the way the universe began chosen by God for reasons we can't understand, or was it determined by a law of science? I believe the second. If you like, you can call the laws of science 'God', but it wouldn't be a personal God that you could meet, and ask questions.

You may see a cup of tea fall off a table and break into pieces on the floor... But you will never see the cup gather itself back together and jump back on the table. The increase of disorder, or entropy, is what distinguishes the past from the future, giving a direction to time.

We are only the temporary custodians of the particles which we are made of. They will go on to lead a future existence in the enormous universe that made them.

I've noticed that even people who believe in fate look both ways before crossing the street.

I don't believe that the ultimate theory will come by steady work along existing lines. We need something new. We can't predict what that will be or when we will find it because if we knew that, we would have found it already!

I'm really easy to get along with once you see it my way.

The human race shouldn't have all its eggs in one basket, or on one planet. Let's hope we can avoid dropping the basket until we have spread the load.

Government works best under the glare of public scrutiny. Absent such scrutiny, abuses occur.

I was not a good student. I did not spend much time at college; I was too busy enjoying myself.

Disability can be no handicap.

There are plenty of dead scientists I admire, but I can't think of any living ones. This is probably because it is only in retrospect that one can see who made the important contributions.

I believe that the long-term future of the human race must be space and that it represents an important life insurance for our future survival, as it could prevent the disappearance of humanity by colonizing other planets.

Doing a job RIGHT the first time gets the job done. Doing the job WRONG fourteen times gives you job security.

Teamwork... means never having to take all the blame yourself.

Though we feel we can choose what we do, our understanding of the molecular basis of biology shows that biological processes are governed by the laws of physics and chemistry and therefore are as determined as the orbits of the planets.

We shouldn't be surprised that conditions in the universe are suitable for life, but this is not evidence that the universe was designed to allow for life. We could call order by the name of God, but it would be an impersonal God. There's not much personal about the laws of physics.

We could call order by the name of God, but it would be an impersonal God. There's not much personal about the laws of physics.

Chaos, when left alone, tends to multiply.

The meaning in life is not out there but inbetween our ears. In many ways this makes us the lords of creation.

When you are faced with the possibility of an early death, it makes you realize that life is worth living and that there are lots of things you want to do.

I'm very interested in film making. It's telling a story, fiction or non-fiction. I have been filmed quite a lot. Contrary to popular belief, filming isn't glamorous. It can be wearingly repetitious, as the same shot is taken over and over again.

It is a waste of time to be angry about my disability. One has to get on with life and I haven't done badly. People won't have time for you if you are always angry or complaining.

Don't be disabled in spirit as well as physically.

We don't let animals suffer, so why humans?

A picture is worth a thousand words...and uses up a thousand times the memory.

Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it.

Why do we remember the past, but not the future?

Hang in there, retirement is only thirty years away!

Now, radical forward thinking is offering hope for the future: Replacement body parts to order. A team of scientists in California believe that if you can design them on a computer, you should be able to print them out.

Then we shall... be able to take part in the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason -- for then we would know the mind of God.

Go the extra mile. It makes your boss look like an incompetent slacker.

It is very important for young people keep their sense of wonder and keep asking why.

Today, we commit to this next great leap into the cosmos because we're human, and our nature is to fly.

Bodies like the earth are not made to move on curved orbits by a force called gravity; instead, they follow the nearest thing to a straight path in a curved space, which is called a geodesic. A geodesic is the shortest (or longest) path between two nearby points.

It is tribute to how far we have come in theoretical physics that it now takes enormous machines and a great deal of money to perform experiments whose results we can not predict.

Because there is a law such as gravity, the Universe can and will create itself from nothing.

Of course it is possible that UFO's really do contain aliens as many people believe, and the government is hushing it up.

The progress of the human race in understanding the universe has established a small corner of order in an increasingly disordered universe.

Over a very small number of rolls of the dice, the uncertainty principle is very important.

In effect, we have redefined the task of science to be the discovery of laws that will enable us to predict events up to the limits set by the uncertainty principle.

At times, I get very lonely because people are afraid to talk to me or don't wait for me to write a response. I'm shy and tongue-tied at times. I find it difficult to talk to people who I don't know.

There should be a better way to start a day than waking up every morning.

In the last 200 years the population of our planet has grown exponentially, at a rate of 1.9% per year. If it continued at this rate, with the population doubling every 40 years, by 2600 we would all be standing literally shoulder to shoulder.

Mankind's greatest achievements have come about by talking and its greatest failures by not talking. It doesn't have to be like this.

What place, then, for a creator?

Science fiction can be exciting and very gripping, but it doesn't tell us anything about the universe in which we live.

The human capacity for guilt is such that people can always find ways to blame themselves.

So great a contribution to physics was Two New Sciences that scholars have long maintained that the book anticipated Isaac Newton's laws of motion.

Before I lost my voice, it was slurred, so only those close to me could understand, but with the computer voice, I found I could give popular lectures. I enjoy communicating science. It is important that the public understands basic science, if they are not to leave vital decisions to others.

The development of full artificial intelligence could spell the end of the human race.

If we ever do find a complete theory of the universe, it would be a great triumph of human reason but it wouldn't leave much for us to do. We need an intellectual challenge.

I don't care much for equations myself. This is partly because it is difficult for me to write them down, but mainly because I don't have an intuitive feeling for equations.

Maxwell is the physicist's physicist.

Only in the few universes that are like ours would intelligent beings develop and ask the question: Why is the universe the way we see it? The answer is then simple: If it had been any different, we would not be here!

There is no prescribed route to follow to arrive at a new idea. You have to make the intuitive leap.

It should soon be possible dramatically to increase the intelligence and life span of a few individuals. They and their offspring could become a master race. Evolution pays no regard to social justice. It was not fair on the Neanderthals they were replaced by modern humans.

My expectations were reduced to zero when I was 21. Everything since then has been a bonus.

I want to encourage public interest in space. I have never let my condition stop me. You only live once.

Our only chance of long-term survival is not to remain lurking on planet Earth, but to spread out into space.

There are no black holes -- in the sense of regimes from which light can't escape to infinity. There are however apparent horizons which persist for a period of time.

One could say: The boundary condition of the universe is that it has no boundary. The universe would be completely self-contained and not affected by anything outside itself. It would neither be created nor destroyed. It would just BE.

A person who smiles in the face of adversity...probably has a scapegoat.

Many people do not like the idea that time has a beginning, probably because it smacks of divine intervention.

Just like a computer, we must remember things in the order in which entropy increases. This makes the second law of thermodynamics almost trivial. Disorder increases with time because we measure time in the direction in which disorder increases. You can't have a safer bet than that!

You cannot understand the glories of the universe without believing there is some Supreme Power behind it.

One should love animals. They are so tasty.

We've created life in our own image.

Nuclear weapons need large facilities, but genetic engineering can be done in a small lab. You can't regulate every lab in the world. The danger is that either by accident or design, we create a virus that destroys us.

Money is not everything. There's Master card and Visa.

God may exist, but science can explain the universe without the need for a creator.

If I had a time machine, I'd visit Marilyn Monroe in her prime or drop in on Galileo as he turned his telescope to the heavens.

Although I cannot move and I have to speak through a computer, in my mind I am free.

So Einstein was wrong when he said, God does not play dice. Consideration of black holes suggests, not only that God does play dice, but that he sometimes confuses us by throwing them where they can't be seen.

What lies north of the North Pole?

Whether you want to uncover the secrets of the universe, or you just want to pursue a career in the 21st century, basic computer programming is an essential skill to learn.

Nothing is fool-proof to a sufficiently talented fool.

Perhaps we could write code to optimize code, then run that code through the code optimizer?

Success is a relative term. It brings so many relatives.

You cannot predict the future.

The beatings will continue until morale improves.

Its a crazy world out there. Be curious.

When the going gets tough, the tough take a coffee break.

Nothing is better than reading and gaining more and more knowledge.

The universe doesn't allow perfection.

I regard the afterlife to be a fairy story for people that are afraid of the dark.

The thing about smart people is that they seem like crazy people to dumb people.

So next time someone complains that you have made a mistake, tell him that may be a good thing. Because without imperfection, neither you nor I would exist.