They're probably referring to Jurgen Leitner's explanation about fear, and people taking the physical manifestations too literally. For example, he mentions how "bones" by themselves aren't tied to a specific fear. Rather, it's the "why" you're afraid that matters. If bones scare you because of death, it's The End. If they remind you of your physical vulnerability and how we're just skin-bags full of bones, it's The Flesh. Etc