there's a fine line between genius and insanity
Proverb expressing that extraordinary talent and madness are separated by only a thin boundary.
Looking at his eccentric ideas, I think there's a fine line between genius and insanity.
A Japanese proverb composed of 天才 (genius), 狂人 (madman), and 紙一重 (paper-thin difference). The exact origin is uncertain, but it reflects a common cross-cultural observation.