Now, we scientists … take it for granted that it is perfectly consistent to be unsure — that it is possible to live and not know. But I don’t know whether everyone realizes that this is true. Our freedom to doubt was born of a struggle against authority in the early days of science. It was a very deep and strong struggle. Permit us to question — to doubt, that’s all — not to be sure. And I think it is important that we do not forget the importance of this struggle and thus perhaps lose what we have gained. Here lies a responsibility to society.