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Something first in a certain order, upon which anything else follows. An order of before and after is found in many things and in different ways. This article merely describes the scholastic notion of principle as applied to nature and to knowledge, and gives some distinctions that are commonly associated with it.

Principles in nature and knowledge. A succession of parts, one after another, is discernible in the material world, not only in the magnitudes of bodies but also in their motion and in time. The order of parts identifiable in local motion, itself most evident to man, enables him to understand the order in other changes. Hence he speaks of the principles of making or generating, which may be either intrinsic to the product or extrinsic to it. The foundation, or first part made in an edifice, is an intrinsic principle; likewise, the first part developed in organic generation, such as the heart or the brain, is such a principle. On the other hand, the mover or source of the motion is an extrinsic principle, as is the end or goal of the agent, insofar as the agent tends to a good beyond itself. The first principles in the order of nature are usually identified as matter, form, and privation (see philosophy of nature; matter and form).

In the learning process, that which first becomes known and leads to further knowledge is called a principle. The basic truths prerequisite for all learning are named axioms; other propositions that are only relatively first and of particular application, whether true or merely probable, are called hypotheses or postulates. According to the natural realism of aristotle and St. thomasaquinas, axioms express reason's grasp of things as intelligible, with their necessary and universal reasons of being. According to Immanuel kant, principles of thought merely express reason's understanding of necessary and universal relationships included in ordinary analytic judgments and, more especially, in judgments referred to as synthetic a priori. Kant doubted whether these principles are valid or true of things distinct from man's knowledge.

Furthermore, the rules and standards of art are called principles. In morals and politics, the rules of conduct and the standards of judgment are similarly referred to as principles, and this term is applied in law to the basic sources from which consequences flow. In each science and art, besides the first principles basic to the whole discipline, there are other principles proper to particular kinds of things included in the general subject. In arithmetic the basic principle is the unit, but each number is a principle of its own properties. Likewise, in geometry the point and the line are basic principles, but particular curves and figures serve as further principles. In physical science also, general principles hold for all natural things, and special principles for special kinds of things. In this way the principles of a science are about as numerous as its conclusions.

Common distinctions. A distinction is usually drawn between a principle and a cause. Every cause is also a principle, but some principles are not causes. Cause implies a certain influence on the being of the thing caused, and is defined as that upon which something follows of necessity and with dependence in being. But for a principle it is sufficient that it be first upon which something follows, whether or not it influences being in another. Moreover, a principle is not always something positive, as a point or part of a line, but may be something negative, as the darkness that precedes dawn, or something privative, as sickness that precedes health recovered.

From the examples given it is evident that the priority signified by a principle is often relative to a certain order under consideration and is not usually absolute or in every order. Only god is the absolutely first and strictly necessary principle (see universe, order of). According to Catholic theology, there are certain principles even in the Holy trinity, as the Father is a principle with respect to the Son, and Father and Son are one common principle with respect to the Spirit.

What is a principle in one respect may be consequent in another respect. Some principles are first and prior in the nature of the case, that is, according to the order of being, whereas others are first only in regard to man's knowledge or consideration. Some principles are first in the order of theoretical knowledge, as the principle of contradiction or the principle of causality, whereas others are first in the order of practical knowledge, as the

principle of doing good and avoiding evil, and of preserving and perfecting the self (see synderesis).

See Also: causality; element; first principles; axiomatic system; postulate; law; theory.

Bibliography: m. j. adler, ed., The Great Ideas: A Syntopicon of Great Books of the Western World (Chicago, Ill. 1952) 2:420436. v. e. smith, General Science of Nature (Milwaukee, Wisc. 1958). g. e. ekbery, First Principles of Understanding (London 1949). a. fossati, Enciclopedia filosofica 3:161516.

[w. h. kane]

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