This cautionary statement appears in Kurt Vonnegut’s 1962 novel “Mother Night,” which presents the purported confessions of Howard W. Campbell Jr., a Nazi propagandist and American spy during World War II. The character discovers his false persona has become indistinguishable from his true self, raising complex questions about identity and morality. Vonnegut, who witnessed the firebombing of Dresden as a prisoner of war, understood how powerful our repeated actions and assumed roles can be — whether they’re adopted consciously or otherwise. If we pretend to be something or someone for long enough — be it for survival, social advantage, or simple experimentation — that pretense can shape our actual identity, potentially in unexpected ways.