When you inoculate children with a polio vaccine, you don't sleep well for two or three months.

I see the triumph of good over evil as a manifestation of the error-correcting process of evolution.

When things get bad enough, then something happens to correct the course. And it's for that reason that I speak about evolution as an error-making and an error-correcting process. And if we can be ever so much better - ever so much slightly better - at error correcting than at error making, then we'll make it.

I have come to recognize evolution not only as an active process that I am experiencing at the time, but as something I can guide by the choices I make.

Risks, I like to say, always pay off. You learn what to do, or what not to do.

I have had dreams and I have had nightmares, but I have conquered my nightmares because of my dreams.

I look upon ourselves as partners in all of this, and that each of us contributes and does what he can do best. And so I see not a top rung and a bottom rung - I see all this horizontally - and I see this as part of a matrix. And I see every human being as having a purpose, a destiny, if you like - the destiny that exists in each of us - and find ways and means to provide such opportunities for everyone.