Reality must take precedence over public relations, for nature cannot be fooled.

It has not yet become obvious to me that there's no real problem. I cannot define the real problem; therefore, I suspect there's no real problem, but I'm not sure there's no real problem.

It is always good to know which ideas cannot be checked directly, but it is not necessary to remove them all. It is not true that we can pursue science completely by using only those concepts which are directly subject to experiment.

The situation in the sciences is this: A concept or an idea which cannot be measured or cannot be referred directly to experiment may or may not be useful. It need not exist in a theory.