I think it's much more interesting to live not knowing than to have answers which might be wrong.

Scientific views end in awe and mystery, lost at the edge in uncertainty, but they appear to be so deep and so impressive that the theory that it is all arranged as a stage for God to watch man's struggle for good and evil seems inadequate.

Know how to solve every problem that has been solved.

But see that the imagination of nature is far, far greater than the imagination of man.

The exception tests the rule.

The present situation in physics is as if we know chess, but we don't know one or two rules.

Only realistic flight schedules should be proposed, schedules that have a reasonable chance of being met. If in this way the government would not support them, then so be it. NASA owes it to the citizens from whom it asks support to be frank, honest, and informative.