We rarely recognize how wonderful it is that a person can traverse an entire lifetime without making a single really serious mistake — like putting a fork in one's eye or using a window instead of a door.

We turn to quantities when we can't compare the qualities of things.

Everything is similar if you're willing to look far out of focus.

You don't understand anything unless you understand there are at least 3 ways.

Common sense is not a simple thing. Instead, it is an immense society of hard-earned practical ideas - of multitudes of life-learned rules and exceptions, dispositions and tendencies, balances and checks.

Anyone could learn Lisp in one day, except that if they already knew Fortran, it would take three days.

This is a tricky domain because, unlike simple arithmetic, to solve a calculus problem - and in particular to perform integration - you have to be smart about which integration technique should be used: integration by partial fractions, integration by parts, and so on.