Principle

In law, higher-order, overarching principles establish rules to be followed, modified by sentencing guidelines relating to context and proportionality. In science and nature, a principle may define the essential characteristics of a system or reflect a system's designed purpose. The effective operation would be impossible if any one of the principles were to be ignored. A system may be explicitly based on and implemented from a document of principles, as was done in IBM's 360/370 Principles of Operation. It is important to differentiate an operational principle, including reference to "first principles," from higher-order "guiding" or "exemplary" principles, such as equality, justice, and sustainability. Higher-order, "superordinate" principles (Super-Ps) provide a basis for resolving differences and building agreement/alignment.

Examples of principles include entropy in a number of fields and least action in physics. Examples in descriptive, comprehensive, and fundamental law include doctrines or assumptions forming normative rules of conduct, such as the separation of church and state in statecraft, the central dogma of molecular biology, fairness in ethics, etc.

In common English, it is a substantive and collective term referring to rule governance, the absence of which, being "unprincipled," is considered a character defect. It may also be used to declare that a reality has diverged from some ideal or norm, as when something is said to be true only "in principle" but not in fact.

As law

As moral law

A principle represents values that orient and rule the conduct of persons in a particular society. To "act on principle" is to act in accordance with one's moral ideals. Principles are absorbed in childhood through a process of socialization. There is a presumption of liberty of individuals that is restrained. Exemplary principles include First, do no harm, the Golden Rule and the Doctrine of the Mean.

As a juridic law

It represents a set of values that inspire the written norms that organize the life of a society submitting to the powers of an authority, generally the state. The law establishes a legal obligation in a coercive way; it therefore acts as a principle conditioning of the action that limits the liberty of the individuals. See, for examples, the territorial principle, the homestead principle, and the precautionary principle.

As scientific law

Archimedes' principle, relating buoyancy to the weight of displaced water, is an early example of a law in science. Another early one developed by Malthus is the population principle, now called the Malthusian principle. Freud also wrote on principles, especially the reality principle necessary to keep the id and pleasure principle in check. Biologists use the principle of priority and principle of Binominal nomenclature for precision in naming species. There are many principles observed in physics, notably in cosmology which observes the mediocrity principle, the anthropic principle, the principle of relativity, and the cosmological principle. Other well-known principles include the uncertainty principle in quantum mechanics and the pigeonhole principle and superposition principle in mathematics.