Stephen Hawking

Imaginary time is a new dimension, at right angles to ordinary, real time.

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.

One can't predict the weather more than a few days in advance.

We define ourselves as intelligent. That's odd, because we're doing the definition - We're creating our own definition and saying, 'We are intelligent!'

If you're not having a good time, find something else that gives you some joy in life.