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?

— Stephen Hawking

Among physicists, I'm respected I hope.

— Stephen Hawking

. . .a scientific theory is just a mathematical model we make to describe our observations: it exists only in our minds. So it is meaningless to ask: which is real, "real" or "imaginary" time? It is simply a matter of which is the more useful description.

— Stephen Hawking

As Irving Good realized in 1965, machines with superhuman intelligence could repeatedly improve their design even further, triggering what Vernon Vine called a 'singularity.'

— Stephen Hawking

A zero-gravity flight is a first step toward space travel.

— Stephen Hawking

Before 1915, space and time were thought of as a fixed arena in which events took place, but which was not affected by what happened in it. Space and time are now dynamic quantities... space and time not only affect but are also affected by everything that happens in the universe.

— Stephen Hawking

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.

— Stephen Hawking

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

— Stephen Hawking

Computers double their performance every month.

— Stephen Hawking

Even if it turns out that time travel is impossible, it is important that we understand why it is impossible.

— Stephen Hawking