No amount of study of present forms [of life] would permit us to infer [the existence of] dinosaurs

If you're too sloppy, then you never get reproducible results, then you never get reproducible results, and then you never can draw any conclusions but if you are just a little sloppy, then when you see something startling, you nail it down. So I called it the Principle of Limited Sloppiness.

[Physicists] feel that the field of bacterial viruses is a fine playground for serious children who ask ambitious questions.

The whole business was like a child's toy that you could buy at the dime store, all built in this wonderful way that you could explain in Life magazine so that really a five-year-old can understand what's going on...This was the greatest surprise for everyone.

Any living cell carries with it the experience of a billion years of experimentation by its ancestors.