My ambition was to bring to bear on medicine a chemical approach. I did that by chemical manipulation of viruses and chemical ways of thinking in biomedical research.

Evolution favors the survival of the wisest.

When I worked on the polio vaccine, I had a theory. I guided each [experiment] by imagining myself in the phenomenon in which I was interested. The intuitive realm . . . the realm of the imagination guides my thinking.

It is courage based on confidence, not daring, and it is confidence based on experience.

Solutions come through evolution. They come through asking the right questions, because the answers pre-exist. It is the questions that we must define and discover. You don't invent the answer-you reveal the answer.

Wisdom: It's something that you know when you see it. You can recognize it, you can experience it. I have defined wisdom as the capacity to make judgments that when looked back upon will seem to have been wise.

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.