"Principle" in the Context of Science

A principle in science is something which is not derived but is simply stated without proof.

Examples:

1. Heizenberg's Uncertainty Principle is not a principle being derived from other quantum mechanical ideas. It is increasingly referred to as "Heizenberg's Uncertainty Relations."
2. The Principle of Microscopic Reversibility is, surprisingly perhaps, not believed to be a consequence of the Second Law of Thermodynamics and therefore constitutes a true principle.

Prin"ci*ple (?), n. [F. principe, L. principium beginning, foundation, fr. princeps, -cipis. See Prince.]

1.

Beginning; commencement.

Doubting sad end of principle unsound. Spenser.

2.

A source, or origin; that from which anything proceeds; fundamental substance or energy; primordial substance; ultimate element, or cause.

The soul of man is an active principle. Tillotson.

3.

An original faculty or endowment.

Nature in your principles hath set [benignity]. Chaucer.

Those active principles whose direct and ultimate object is the communication either of enjoyment or suffering. Stewart.

4.

A fundamental truth; a comprehensive law or doctrine, from which others are derived, or on which others are founded; a general truth; an elementary proposition; a maxim; an axiom; a postulate.

Therefore, leaving the principles of the doctrine of Christ, let us go on unto perfection. Heb. vi. 1.

A good principle, not rightly understood, may prove as hurtful as a bad. Milton.

5.

A settled rule of action; a governing law of conduct; an opinion or belief which exercises a directing influence on the life and behavior; a rule (usually, a right rule) of conduct consistently directing one's actions; as, a person of no principle.

All kinds of dishonesty destroy our pretenses to an honest principle of mind. Law.

6. Chem.

Any original inherent constituent which characterizes a substance, or gives it its essential properties, and which can usually be separated by analysis; -- applied especially to drugs, plant extracts, etc.

Cathartine is the bitter, purgative principle of senna. Gregory.

Bitter principle, Principle of contradiction, etc. See under Bitter, Contradiction, etc.

© Webster 1913.

Prin"ci*ple (?), v. t. [imp. & p. p. Principled (?); p. pr. & vb. n. Principling (?).]

To equip with principles; to establish, or fix, in certain principles; to impress with any tenet, or rule of conduct, good or ill.

Governors should be well principled. L'Estrange.

Let an enthusiast be principled that he or his teacher is inspired. Locke.

© Webster 1913.