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English theoretical physicist and cosmologist (1942- )

Disorder increases with time because we measure time in the direction in which disorder increases.

STEPHEN HAWKING, A Brief History of Time

What I have done is to show that it is possible for the way the universe began to be determined by the laws of science. In that case, it would not be necessary to appeal to God to decide how the universe began. This doesn't prove that there is no God, only that God is not necessary.

STEPHEN HAWKING, Der Spiegel, Oct. 17, 1988

I think computer viruses should count as life ... I think it says something about human nature that the only form of life we have created so far is purely destructive. We've created life in our own image.

STEPHEN HAWKING, The Daily News, Aug. 4, 1994

Our brains interpret the input from our sensory organs by making a model of the world. When such a model is successful at explaining events, we tend to attribute to it, and to the elements and concepts that constitute it, the quality of reality or absolute truth. But there may be different ways in which one could model the same physical situation, with each employing different fundamental elements and concepts. If two such physical theories or models accurately predict the same events, one cannot be said to be more real than the other; rather, we are free to use whichever model is most convenient.


So long as the universe had a beginning, we could suppose it had a creator. But if the universe is really completely self-contained, having no boundary or edge, it would have neither beginning nor end: it would simply be. What place, then, for a creator?

STEPHEN HAWKING, A Brief History of Time

If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans.... We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet.

STEPHEN HAWKING, Into the Universe with Stephen Hawking

The whole history of science has been the gradual realization that events do not happen in an arbitrary manner, but that they reflect a certain underlying order, which may or may not be divinely inspired.

STEPHEN HAWKING, A Brief History of Time

There ought to be something very special about the boundary conditions of the universe and what can be more special than that there is no boundary?

STEPHEN HAWKING, attributed, The Anthropic Cosmological Principle

According to quantum physics, no matter how much information we obtain or how powerful our computing abilities, the outcomes of physical processes cannot be predicted with certainty because they are not determined with certainty.


God abhors a naked singularity.

STEPHEN HAWKING, A Brief History of Time

I don't think the human race will survive the next thousand years, unless we spread into space. There are too many accidents that can befall life on a single planet. But I'm an optimist. We will reach out to the stars.

STEPHEN HAWKING, The Daily Telegraph, Oct. 16, 2001

Ignorance of nature's ways led people in ancient times to invent gods to lord it over every aspect of human life. There were gods of love and war; of the sun, earth, and sky; of the oceans and rivers; of rain and thunderstorms; even of earthquakes and volcanoes. When the gods were pleased, mankind was treated to good weather, peace, and freedom from natural disaster and disease. When they were displeased, there came draught, war, pestilence, and epidemics. Since the connection of cause and effect in nature was invisible to their eyes, these gods appeared inscrutable, and people at their mercy.


Even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe? The usual approach of science of constructing a mathematical model cannot answer the questions of why there should be a universe for the model to describe. Why does the universe go to all the bother of existing?

STEPHEN HAWKING, A Brief History of Time

We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special.

STEPHEN HAWKING, Der Spiegel, Oct. 17, 1988

A few years ago the city council of Monza, Italy, barred pet owners from keeping goldfish in curved goldfish bowls. The measure's sponsor explained the measure in part by saying that it is cruel to keep a fish in a bowl with curved sides because, gazing out, the fish would have a distorted view of reality. But how do we know we have the true, undistorted picture of reality? Might not we ourselves also be inside some big goldfish bowl and have our vision distorted by an enormous lens? The goldfish's picture of reality is different from ours, but can we be sure it is less real?


Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory. As philosopher of science Karl Popper has emphasized, a good theory is characterized by the fact that it makes a number of predictions that could in principle be disproved or falsified by observation. Each time new experiments are observed to agree with the predictions the theory survives, and our confidence in it is increased; but if ever a new observation is found to disagree, we have to abandon or modify the theory.

STEPHEN HAWKING, A Brief History of Time

If we do discover a complete theory, it should in time be understandable in broad principle by everyone, not just a few scientists. Then we shall all, philosophers, scientists, and just ordinary people, 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.

STEPHEN HAWKING, Black Holes and Baby Universes and Other Essays

I have noticed even people who claim everything is predestined, and that we can do nothing to change it, look before they cross the road.

STEPHEN HAWKING, attributed, Words from the Wise

I'm sorry to disappoint science fiction fans, but if information is preserved, there is no possibility of using black holes to travel to other universes. If you jump into a black hole, your mass energy will be returned to our universe but in a mangled form which contains the information about what you were like but in a state where it can not be easily recognized. It is like burning an encyclopedia. Information is not lost, if one keeps the smoke and the ashes. But it is difficult to read. In practice, it would be too difficult to re-build a macroscopic object like an encyclopedia that fell inside a black hole from information in the radiation, but the information preserving result is important for microscopic processes involving virtual black holes.

STEPHEN HAWKING, "Information Loss in Black Holes," July 2005

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

STEPHEN HAWKING, attributed, The Gigantic Book of Teachers' Wisdom

For millions of years, mankind lived just like the animals. Then something happened which unleashed the power of our imagination. We learned to talk and we learned to listen. Speech has allowed the communication of ideas, enabling human beings to work together to build the impossible. Mankind's greatest achievements have come about by talking, and its greatest failures by not talking. It doesn't have to be like this. Our greatest hopes could become reality in the future. With the technology at our disposal, the possibilities are unbounded. All we need to do is make sure we keep talking.

STEPHEN HAWKING, British Telecom advertisement, 1993

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