A professor of mine once said to me that all teaching was a process of
lying, and then of replacing the lies with successively better
approximations of the truth. “I say it's like this,” he said, “and
then later I say, well, it's not actually like that, it's more like
this, because the real story is too complicated to explain all at
once.” I wouldn't have phrased it like this, but I agree with him in
principle. One of the most important issues in pedagogical practice
is deciding what to leave out, and for how long.

A professor of mine once said to me that all teaching was a process of
lying, and then of replacing the lies with successively better
approximations of the truth. “I say it's like this,” he said, “and
then later I say, well, it's not actually like that, it's more like
this, because the real story is too complicated to explain all at
once.” I wouldn't have phrased it like this, but I agree with him in
principle. One of the most important issues in pedagogical practice
is deciding what to leave out, and for how long.