"If you keep proving stuff that others have done, getting confidence, increasing the complexities of ..." — Richard P. Feynman

From the point of view of basic physics, the most interesting phenomena are, of course, in the new places, the places where the rules do not work - not the places where they do work! That is the way in which we discover new rules.

The correct statement of the laws of physics involves some very unfamiliar ideas which require advanced mathematics for their description. Therefore, one needs a considerable amount of preparatory training even to learn what the words mean.

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.

Once you have a computer that can do a few things - strictly speaking, one that has a certain 'sufficient set' of basic procedures - it can do basically anything any other computer can do. This, loosely, is the basis of the great principle of 'Universality'.