A room that answers perfectly in Chinese without understanding a word

Imagine someone who speaks no Chinese, locked in a room with a rulebook telling them exactly which Chinese symbols to output for any symbols slipped under the door. From outside, the responses look fluent — but the person inside understands nothing. John Searle used this to argue that a computer following a program, however convincingly it talks, doesn't thereby understand anything either.

— John Searle, Minds, Brains, and Programs — Behavioral and Brain Sciences, 1980