The
Latin term
ab initio means
from the beginning and is used in several contexts:
- when describing literature: told from the beginning as opposed to in medias res (meaning starting in the middle of the story)
- as a legal term: 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: A calculation is said to be "ab initio" (or "from first principles") if it relies on basic and established laws of nature without additional assumptions or special models.