Reply when questioned on the safety of the polio vaccine he developed: It is safe, and you can't get safer than safe.

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

I pictured myself as a virus or a cancer cell and tried to sense what it would be like.

This is perhaps the most beautiful time in human history; it is really pregnant with all kinds of creative possibilities made possible by science and technology which now constitute the slave of man - if man is not enslaved by it.

There is a moment of conception and a moment of birth, but between them there is a long period of gestation.

If all the insects were to disappear from the earth, within 50 years all life on earth would end. If all human beings disappeared from the earth, within 50 years all forms of life would flourish.

Intuition will tell the thinking mind where to look next.