By concentrating on what, and leaving out why, mathematics is
reduced to an empty shell. The art is not in the "truth" but in
the explanation, the argument. It is the argument itself which
gives the truth its context, and determines what is really being
said and meant. Mathematics is the art of explanation. If you
deny students the opportunity to engage in this activity -- to
pose their own problems, make their own conjectures and
discoveries, to be wrong, to be creatively frustrated, to have an
inspiration, and to cobble together their own explanations and
proofs -- you deny them mathematics itself. So no, I'm not
complaining about the presence of facts and formulas in our
mathematics classes, I'm complaining about the lack of
mathematics in our mathematics classes.