Tell a man there are 300 billion stars in the universe and he'll believe you. Tell him a bench has wet paint on it and he'll have to touch it to be sure.

This is a modern, anonymous humorous aphorism that circulates widely in joke books, office posters, and online quotation collections. It plays on a familiar everyday scenario—someone ignoring a “Wet Paint” warning and touching the surface anyway—to contrast how readily people accept abstract, unverifiable claims (like astronomical numbers) while distrusting immediate, practical cautions unless they can test them firsthand. The line is typically presented as a standalone quip rather than tied to a particular speech, essay, or identifiable individual, and it functions more as folk humor about human nature than as a traceable literary citation.

The joke highlights a paradox in human credulity: we often accept grand, impersonal facts on authority because they carry little personal cost, yet we become skeptical about simple warnings that directly constrain our behavior. Touching the “wet paint” becomes a symbol of compulsive verification and curiosity, even when the evidence is clearly posted. Beneath the humor is a comment on epistemology and risk: people outsource belief about distant, technical matters to experts, but demand personal proof for immediate claims—sometimes even when that proof is messy or unnecessary. It gently satirizes stubbornness and the desire to learn by direct experience.

1) “Tell a man there are billions of stars in the universe and he’ll believe you. Tell him there’s wet paint and he has to touch it to be sure.”
2) “Tell someone there are 300 billion stars in the universe and they’ll believe you. Tell them a bench is wet and they’ll touch it.”
3) “Tell a man there are 300 billion stars in the universe and he’ll believe you. Tell him paint is wet and he’ll have to touch it.”