"We were told in one lecture that it was possible to immunize against diphtheria and tetanus by the use of chemically treated toxins, or toxoids. And the following lecture, we were told that for immunization against a virus disease, you have to experience the infection, and that you could not induce immunity with the so-called "killed" or inactivated, chemically treated virus preparation. Well, somehow, that struck me. What struck me was that both statements couldn't be true. And I asked why this was so, and the answer that was given was in a sense, 'Because.' There was no satisfactory answer."

"Some people are constructive, if you like. Others are destructive. It's this diversity in humankind that results in some making positive contributions and some negative contributions. It's necessary to have enough who make positive contributions to overcome the problems of each age."

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

"I was told I could, if I wished, switch and get a Ph.D. in biochemistry but my preference was to stay with medicine. And I believe that this is all linked to my original ambition, or desire, which was to be of some help to humankind, so to speak, in a larger sense than just on a one-to-one basis. Just as I intended to study law, to make just laws, so I found myself interested now in the laws of nature, as distinct from the laws the people make."

"As a child I was not interested in science. I was merely interested in things human, the human side of nature, if you like, and I continue to be interested in that. That's what motivates me."

"I already see enough evidence for this optimism … in recent years I find that perhaps what Im seeking is a scientific basis for hope, and I think I've found it."

"Edward R. Murrow: Who owns the patent on this vaccine? Jonas Salk: Well, the people, I would say. There is no patent. Could you patent the sun?"

"There is something about human nature that has to be understood, and so … I've shifted my attention from an interest in unity to an interest in creativity."

"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. And what my hope is that we can find some way to fulfill the biological potential, if you like — the destiny that exists in each of us — and find ways and means to provide such opportunities for everyone. Now at the moment the world is suffering from large numbers of people who have no purpose in life — for whom there is no opportunity — and that's sad."

"Richard Heffner: You say "We can create ourselves and our future" Salk: — by shaping our selves not our cells — thats the important distinction. … We are shaping our cells, but we will not change our selves in the course of shaping our cells."

"As a bio-philosopher — as someone who draws upon the scriptures of nature, recognizing that we are the product of the process of evolution, and in a sense, we have become the process itself — through the emergence and evolution of our consciousness, our awareness, our capacity to imagine and to anticipate the future and to choose from amongst alternatives."

"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."

"What is … important is that we — number one: Learn to live with each other. Number two: try to bring out the best in each other. The best from the best, and the best from those who, perhaps, might not have the same endowment. And so this bespeaks an entirely different philosophy — a different way of life — a different kind of relationship — where the object is not to put down the other, but to raise up the other."

"I have the impression that the new generation of young people, are coming up on the scene with a sense "ancestorhood", and with more wisdom than was evident before. I think this comes about as a matter of necessity — Almost as if there is something in us that is innate, something inherent in us, that is destined for a longer term, rather than a shorter term future."

"I couldn't possibly have become a member of this institute if I hadn't founded it myself."

"I have dreams, and I have nightmares. I overcame the nightmares because of my dreams."

"Our greatest responsibility is to be good ancestors."

"Neither wisdom nor good will is now dominant. Hope lies in dreams, in imagination and in the courage of those who dare to make dreams into reality."

"Nothing happens quite by chance. It's a question of accretion of information and experience … it's just chance that I happened to be here at this particular time when there was available and at my disposal the great experience of all the investigators who plodded along for a number of years."

"Why did Mozart compose music?"