And those who were seen dancing were thought to be insane by those who could not hear the music.

We searched Nietzsche's major works — Thus Spoke Zarathustra, The Gay Science, Beyond Good and Evil, Twilight of the Idols — as well as his letters and notebooks in the authoritative Colli–Montinari critical edition, and found no passage matching this line in German ("Und die man tanzen sah...") or in any reputable English translation. A dedicated investigation of the saying likewise found no match in Nietzsche's corpus, tracing close forms only to late-20th-century circulation (the earliest cited around 1981), well after his death in 1900. The book database returns are all recent and derivative — titles like Roger Ball's Mindshifts (2025), Blake D. Bauer's You Were Not Born to Suffer (2012), and Gregory Causey's Dancing With Natasha (2007) all simply repeat the line with Nietzsche's name and add no provenance. The sentiment is genuinely "Nietzschean" — he did prize dancing and music as metaphors, which is likely why the line attached itself to him — but thematic resemblance is not authorship, and the aphoristic, inspirational phrasing reads more like modern quote culture than 19th-century philosophical prose. Crucially, while we strongly doubt Nietzsche wrote it, we cannot name a specific competing author or a documented earlier source that originated the line, so the strict bar for "misattributed" is not met. The line is widely and commonly credited to Nietzsche across many sources but remains unsupported by any primary evidence: attributed.