The Dungeons and Dragons Paradox
My daughter Hannah taught me a delicious paradox from the role-playing game "Dungeons and Dragons". In D&D there is such a thing as a Truth Zone; when your character is in a Truth Zone, then by the rules your character must tell the truth. But in D&D there is also such a thing as a Compulsive Liar Spell; when your character is hit with a Compulsive Liar Spell, then by the rules your character must tell lies. Normally such contradictory magic cancels out in D&D; but in this case they stack up. Therefore if your character is in a Truth Zone and is hit by a Compulsive Liar Spell, then by the rules your character must speak in paradoxes!
Hannah says that one way in D&D to get around the compulsive-liar-in-a-truth-zone paradox is for your character to speak in metaphor and fiction. Lies to tell the truth. Of course this can be tricky - as authors well know.
It occurs to me that a compulsive liar in a truth zone is a metaphor for the human condition. We live in the Universe, which is a truth zone; tell the truth or be expelled from the Universe. But we also live in human society; therefore we are hit with a compulsive liar spell; tell lies or be expelled from human society. Therefore fiction; telling lies to tell the truth.