Once I wept for I had no shoes. Then I met a man with no feet, so I took his shoes. I mean, it wasn't as if he was going to need them.
Stephen HawkingObservations indicate that the universe is expanding at an ever increasing rate. It will expand forever, getting emptier and darker.
Stephen HawkingAny physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it.
Stephen HawkingOne might think this means that imaginary numbers are just a mathematical game having nothing to do with the real world. From the viewpoint of positivist philosophy, however, one cannot determine what is real. All one can do is find which mathematical models describe the universe we live in. It turns out that a mathematical model involving imaginary time predicts not only effects we have already observed but also effects we have not been able to measure yet nevertheless believe in for other reasons. So what is real and what is imaginary? Is the distinction just in our minds?
Stephen Hawking