I prefer concrete things and I don't like to learn more about abstract stuff than I absolutely have to. - Mark Kac

Unrestricted abstraction tends to divert attention from whole areas of application whose very discovery depends of the features that the abstract point of view rules out as being accidental.

When one is young, and seventeen is very young, one lives in the present. The future, even the near future, is cloaked in unreality.

Independence is the central concept of probability theory and few would believe today that understanding what it meant was ever a problem.