Translation of "ab initio" into English

"At the outset", referring to an inquiry or investigation. In literature, refers to a story told from the beginning rather than in medias res|from the middle|. In law, refers to something being the case from the start or from the instant of the act, rather than from when the court declared it so. A judicial declaration of the invalidity of a marriage ab initio is a nullity. In science, refers to the first principles. In other contexts, often refers to beginner or training courses. Ab initio mundi means "from the beginning of the world".