There are plenty of dead scientists I admire, but I can't think of any living ones. This is probably because it is only in retrospect that one can see who made the important contributions.

Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory.

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.

There should be no boundaries to human endeavor. However bad life may seem, there is always hope.

Why does the universe go to all the bother of existing?

A lot of prizes have been awarded for showing the universe is not as simple as we might have thought.

[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.