The phlogiston theory is a chemical hypothesis that was supported in the 18th century. According to this theory, all flammable materials contain an element called phlogiston and, when a substance is burned, its phlogiston is released and the remaining ash is held to be its true form. The background of the phlogiston theory was the desire for catharsis exemplified in witch-hunts and bloodletting in the early modern era. As to the former people thought burning witches at the stake could expel Satanism from them, lighten their sins as well as their physical weight and reduces them to their true forms. As to the latter they thought bloodletting could expel the cause of diseases from the body, lighten their symptom and reduce patients to their true healthy forms.

A scapegoat is, in the original Hebrew sense, a goat symbolically burdened with the sins of the ancient Jewish people. By extension, it has come to mean any group or individual that innocently bears the blame of others. What kind of beings are candidates of scapegoats?