Stephen Hawking

We are all different. There is no such thing as a standard or run-of-the-mill human being, but we share the same human spirit.

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.

Success in creating AI would be the biggest event in human history. Unfortunately, it might also be the last, unless we learn how to avoid the risks.

In my school, the brightest boys did math and physics, the less bright did physics and chemistry, and the least bright did biology. I wanted to do math and physics, but my father made me do chemistry because he thought there would be no jobs for mathematicians.

We are in danger of destroying ourselves by our greed and stupidity. We cannot remain looking inwards at ourselves on a small and increasingly polluted and overcrowded planet.

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.

Work gives you meaning and purpose and life is empty without it.

A few years ago, the city council of Monza, Italy, barred pet owners from keeping goldfish in curved bowls... 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?

As scientists, we step on the shoulders of science, building on the work that has come before us — aiming to inspire a new generation of young scientists to continue once we are gone.

Life would be tragic if it weren't funny.

While physics and mathematics may tell us how the universe began, they are not much use in predicting human behavior because there are far too many equations to solve. I'm no better than anyone else at understanding what makes people tick, particularly women.

I believe alien life is quite common in the universe, although intelligent life is less so. Some say it has yet to appear on planet Earth.

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

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

My advice to other disabled people would be, concentrate on things your disability doesn't prevent you doing well, and don't regret the things it interferes with. Don't be disabled in spirit as well as physically.

Stem cell research is the key to developing cures for degenerative conditions like Parkinson's and motor neuron disease from which I and many others suffer. The fact that the cells may come from embryos is not an objection, because the embryos are going to die anyway.

Look up at the stars and not down at your feet. Try to make sense of what you see, and wonder about what makes the universe exist. Be curious.

However difficult life may seem, there is always something you can do and succeed at.

With genetic engineering, we will be able to increase the complexity of our DNA, and improve the human race. But it will be a slow process, because one will have to wait about 18 years to see the effect of changes to the genetic code.

The past, like the future, is indefinite and exists only as a spectrum of possibilities.