On knowing until asked
“What then is time? If no one asks me, I know; if I wish to explain it to one who asks, I know not.”
Augustine is being exact rather than clever. He does know what time is, in the way anyone knows it — he uses it, measures it, waits through it. The knowledge simply will not survive being put into words.
Most of what a person actually knows is like this. It works while it stays unexamined and dissolves under a direct question, which is worth remembering before treating the ability to explain something as the test of understanding it.