Smart people analyze and think.
They gather information from diverse sources and analyze everything, thinking for themselves and deciding what is right.
They search for the truth and are willing to learn.
They understand how the world works.
They can explain things clearly and easily because they truly understand them.
When they hear something they disagree with, they stop, think, and try to understand why it was said, looking for what they can learn. An open and curious mind is necessary for progress.