The most valuable and least replacable resource is time.

A problem never exists in isolation; it is surrounded by other problems in space and time. The more of the context of a problem that a scientist can comprehend, the greater are his chances of finding a truly adequate solution.

Successful problem solving requires finding the right solution to the right problem. We fail more often because we solve the wrong problem than because we get the wrong solution to the right problem.

Common sense … has the very curious property of being more correct retrospectively than prospectively. It seems to me that one of the principal criteria to be applied to successful science is that its results are almost always obvious retrospectively; unfortunately, they seldom are prospectively. Common sense provides a kind of ultimate validation after science has completed its work; it seldom anticipates what science is going to discover.

Every problem interacts with other problems and is therefore part of a set of interrelated problems, a system of problems. I choose to call such a system a mess.

Nothing is harder to topple than a fact that supports a deeply held prejudice denied by its holder.

A bureaucrat is one who has the power to say "no" but none to say "yes."