The early Buddhist texts suggest that Buddha faced a difficulty in explaining what is reborn and how rebirth occurs, after he innovated the concept that there is "no self" ("Anatta"). Later Buddhist scholars, such as the mid-1st millennium CE Pali scholar Buddhaghosa, suggested that the lack of a self or soul does not mean lack of continuity; and the rebirth across different realms of birth – such as heavenly, human, animal, hellish and others – occurs in the same way that a flame is transferred from one candle to another. Buddhaghosa attempted to explain rebirth mechanism with "rebirth-linking consciousness" ("patisandhi").