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.

Maybe I don't have the most common kind of motor neuron disease, which usually kills in two or three years.

We should seek the greatest value of our action.

While there's life, there is hope.

It is tribute to how far we have come in theoretical physics that it now takes enormous machines and a great deal of money to perform experiments whose results we can not predict.

My expectations were reduced to zero when I was 21. Everything since then has been a bonus.

The real challenge is to work out what aliens might actually be like.