According to Osho, the sun does not only appear in the day; it is there at night too, yet darkness makes it invisible to us. His playful reply points to a deeper truth: reality is ever-present, but our perception depends on conditions. When ignorance (darkness) lifts, what is always present (the sun/truth) becomes obvious.
The sun is always there, but at night it’s hidden by darkness—like truth you can’t see until you switch on inner light.