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

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.

Nothing happens quite by chance. It's a question of accretion of information and experience.

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

A good parent gives their child roots and wings.

I overcame the nightmares because of my dreams.

Intuition will tell the thinking mind where to look next.