( ) is a Latin term meaning "from the beginning" and is derived from the Latin ("from") + , ablative

singular Singular may refer to: * Singular, the grammatical number that denotes a unit quantity, as opposed to the plural and other forms * Singular or sounder, a group of boar, see List of animal names * Singular (band), a Thai jazz pop duo *'' Singula ...

of ("beginning").

Etymology

, from Latin, literally "from the beginning", from ablative case of "entrance", "beginning", related to verb "to go into", "enter upon", "begin".

Uses

''Ab initio'' (abbreviation: ''ab init.'') is used in several contexts, including the following:

Law

law Law is a set of rules that are created and are enforceable by social or governmental institutions to regulate behavior, with its precise definition a matter of longstanding debate. It has been variously described as a science and as the ar ...

, ''ab initio'' 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. For instance, the term "void ''ab initio''" means "to be treated as invalid from the outset." E.g., in many

jurisdiction Jurisdiction (from Latin 'law' and 'speech' or 'declaration') is the legal term for the legal authority granted to a legal entity to enact justice. In federations like the United States, the concept of jurisdiction applies at multiple level ...

s, if a person signs a contract under duress, that contract is treated as being "void ''ab initio''". Typically, documents or acts which are void ''ab initio'' cannot be fixed and if a jurisdiction, a document, or an act is so declared at law to be void ''ab initio'', the parties are returned to their respective positions that they were at the beginning of the event. "Void ''ab initio''" is often contrasted with "voidable" ''in futuro'', such documents which become void only as of the date of a certain event or of the judicial declaration to that effect. For example, termination of a contract only operates ''in futuro''. An insurer facing a claim from an insured who had deceived the insurer on a material fact would claim that the insurance contract was void ''ab initio''; it was null and void from the beginning and that since there was no legally enforceable contract, the insurer ought not to have to pay.

Science and engineering

In general, a calculation is said to be ''ab initio'' (or "from

first principles In philosophy and science, a first principle is a basic proposition or assumption that cannot be deduced from any other proposition or assumption. First principles in philosophy are from first cause attitudes and taught by Aristotelians, and nuan ...

") if it relies on basic and established laws of nature without additional assumptions or special models. For example, an ''ab initio'' calculation of the properties of liquid water might start with the properties of the constituent hydrogen and oxygen atoms and the laws of electrostatics and quantum mechanics. From these basics, the properties of isolated individual water molecules would be derived, followed by computations of the interactions of larger and larger groups of water molecules, until the bulk properties of water had been determined. This in contrast to an approach that uses approximations (which could allow for easier computations) that have no direct link to these first principles. *

Documentation Documentation is any communicable material that is used to describe, explain or instruct regarding some attributes of an object, system or procedure, such as its parts, assembly, installation, maintenance, and use. As a form of knowledge managem ...

of a process is said to be ''ab initio'' (or '' from scratch'', or '' from the ground up'') if the documentation shows how to set up and complete the process from basic materials (to which a competent practitioner is expected to have access) without prior special preparation. * In

nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies th ...

, the mass-energy of different nuclei can be determined with ''ab initio'' methods by solving the

Schrödinger equation The Schrödinger equation is a partial differential equation that governs the wave function of a non-relativistic quantum-mechanical system. Its discovery was a significant landmark in the development of quantum mechanics. It is named after E ...

over all particles. * Likewise in

chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...

, this refers to ''ab initio'' quantum chemistry methods. * In

biophysics Biophysics is an interdisciplinary science that applies approaches and methods traditionally used in physics to study biological phenomena. Biophysics covers all scales of biological organization, from molecular to organismic and populations ...

, this refers to a method for the prediction of protein structures in protein folding. * In

bioinformatics Bioinformatics () is an interdisciplinary field of science that develops methods and Bioinformatics software, software tools for understanding biological data, especially when the data sets are large and complex. Bioinformatics uses biology, ...

, ''ab initio'' (or '' de novo'') methods make predictions about biological features using only a computational model without extrinsic comparison to existing data. * In

aviation Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' include fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air aircraft such as h ...

, this refers to the first stage of flight training.

Other uses

* In

literature Literature is any collection of Writing, written work, but it is also used more narrowly for writings specifically considered to be an art form, especially novels, Play (theatre), plays, and poetry, poems. It includes both print and Electroni ...

, a story told ''ab initio'' is told from the beginning;

Horace Quintus Horatius Flaccus (; 8 December 65 BC – 27 November 8 BC), Suetonius, Life of Horace commonly known in the English-speaking world as Horace (), was the leading Roman lyric poet during the time of Augustus (also known as Octavian). Th ...

called this method '' ab ovo'' ('from the egg'). This is as opposed to ''

in medias res A narrative work beginning ''in medias res'' (, "into the middle of things") opens in the chronological middle of the plot, rather than at the beginning (cf. '' ab ovo'', '' ab initio''). Often, exposition is initially bypassed, instead filled i ...

'' (in the middle of the story). * In

Aviation Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' include fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air aircraft such as h ...

, ''ab initio'' flight training refers to a pilot training program that starts from zero flight experience. * In learning a subject or foreign language, ''ab initio'' refers to study without previous knowledge or assumptions.

References

External links

Definition at Dictionary.com
{{Webarchive, url=https://web.archive.org/web/20121025135828/http://dictionary.reference.com/cite.html?qh=ab+initio&ia=mwlaw , date=2012-10-25 Latin legal terminology Latin literary phrases Narrative techniques