[In the Universe it may be that] Primitive life is very common and intelligent life is fairly rare. Some would say it has yet to occur on Earth.

Success is a relative term. It brings so many relatives.

In Britain, like most of the developed world, stem-cell research is regarded as a great opportunity. America will be left behind if it doesn't change policy.

As those who have seen Jurassic Park will know, this means a tiny disturbance in one place, can cause a major change in another. A butterfly flapping its wings can cause rain in Central Park, New York. The trouble is, it is not repeatable. The next time the butterfly flaps its wings, a host of other things will be different, which will also influence the weather. That is why weather forecasts are so unreliable.

Time and space are finite in extent, but they don't have any boundary or edge. They would be like the surface of the earth, but with two more dimensions.

Children in backseats cause accidents. Accidents in backseats cause children.

We live in the most probable of all possible worlds.