“Dr P.” had a vision problem. He could see 20/20, but somehow he lost his ability to read music—a significant problem for a music teacher. It gets worse. He also stopped being able to recognize people, at least when he could not hear their voices or see distinctive facial features. Abstracts weren’t a problem—he identified squares, circles, even a dodecahedron. He could see. But there he was trying to have conversations with fire hydrants, and genuinely mistaking his wife for a hat.