Silence is the only effective response to the fool.
While ignorance is a lack of data, the “fool” is one who clings to fragments of knowledge as a life raft, fearing that a single rethink would dissolve their identity: ego death.
Presenting facts to a clenched ego is futile; they are closed to words. Instead, striving to relax them with quiet understanding—rather than irritation—may plant a seed of wisdom.
On the other hand, the fool’s greatest gift is the mirror they hold up: they reveal your own foolishness and your desperate, reflexive need to be right.