To distinguish it from philosophy and art requires an understanding of the terms law, principle, and rule; and these words involve as much confusion as the others. It will, therefore, be necessary to distinguish these first. 3. RULE.-This word means, first, a guide, a material edge or face, by resting against which a moving object will take the shortest distance between two points. It marks the limit of our ability to make a straight line, or to find the shortest distance spoken of. In the second place, the word is applied to action. When two persons have the same thing to do, and one does it more easily and more quickly than the other, the shorter method is adopted as a guide or rule for doing that thing. A rule of action, then, like the material rule, is a guide or direction, by following which a given thing can be best performed. A perfect rule marks the limit of facility or economy in work.

4. PRINCIPLE.-The term principle is from a Latin word which means leader, head, chief, and is used in an absolute and in a relative sense.

a. It is a conception, or that in nature which is supposed to correspond with a conception, that has a leading or controlling influence in a particular thought or line of reasoning. In its absolute sense it is an ultimate element of analysis, or an ultimate form of consciousness, a conception which can not be analyzed by us. It may be something thought of as existing, such as a quality of matter, a faculty, life, physical force, or the conception of such an element, and it is then called. a principle of being; or it may be the conception of a relation, such as cause and effect, justice, law, and it is then called a principle of the understanding. On the development of these fundamental principles all our knowledge rests, perception depending upon principles

of being, and reasoning on principles of the understanding. They are the limit of thought in every direction, and though they may not be ultimate in themselves, they are ultimate for us in thinking.

b. But we do not always go back to ultimate principles in considering a subject. The value and construction of a steam-engine depend upon the power of steam and the action of levers, and we say the principles of the steamengine are the expansiveness of steam and the lever. We do not need to analyze these in order to understand the engine. Any force, mode of action, or material form that enters as a unit into that which we are studying, is a principle in relation to that thing, and is particularly called such if it has a leading influence in determining its character. This is the more frequent use of the term. In this sense, a principle is one of the results obtained in the last analysis of a subject required for a complete understanding of it. Pure mathematics must go back to first principles, or the ultimate conceptions of the mind; but applied mathematics, like Surveying and Astronomy, may rest upon principles derived by mathematical reasoning.

5. LAW.-a. When a principle is to be used as a fixed standard of judgment, it is limited to such a series or class of objects as show uniform relations to each other, and stated in terms of the objects related; and the principle thus limited and applied is called a law. For instance, when the principle of justice is applied to contracts we have the law of contracts, setting forth the obligations of two parties under given conditions, and laying a penalty on either who may fail to carry out his part of the contract. The principle of causation is applied to the production of heat, and we have the law that a given amount of coal, when consumed, will pro

duce a given amount of heat. We are not always able to reduce a principle to satisfactory laws, but a law must always involve a principle. The value of a law depends upon the extent and accuracy of its embodiment of a principle or principles.

b. The ancient Greeks developed more of what may be called the ultimate principles of nature and of human action than all other peoples of antiquity, if the history that has come down to us is a reliable test, and they set them forth most sharply defined. From these principles the Romans developed laws, and were, above all other nations, a nation of law. Even their language was marked by this characteristic. If we accept the etymology of the Latin word for law given by Mommsen, we shall find in that the fundamental idea here presented. He supposes the word lex, law, to be derived from a word meaning to depute. A king required his subjects to obey his will. But the circumstances in which men were liable to be placed varied so greatly that, however well they might understand the king's disposition, they could not always tell in his absence what his will was. To make provision for this uncertainty,-out of deference, as it were, to the ignorance and inability of his subjects,—the king set forth a statement of what he would always require, exact, or inflict, under given circumstances. This statement was to represent his will to his subjects, and was to be so regarded, both by him and by them. In a

similar way, the absolute nature of matter and force is unknown to man; he can not trace objects, actions, and motives to their ultimate elements; but there are recorded in the constitution of his reason laws which represent to him, within definite limits, when developed into consciousness, the mode in which matter and force act under certain circumstances. A law does not attempt to repre

sent a principle in more than one aspect, and, in our imperfect apprehension, does not generally represent this aspect exactly, or there would be no exceptions. A law can not be more true than the principle on which it rests, but it is more definite in the understanding, and it is held more clearly in consciousness. Could we stand at the source of all physical and spiritual changes, with the ability to trace each active power from event to event through the entire series, we would need no law to help our understanding. The necessity of law implies the impossibility of exact knowledge of the reality itself. But inexactness does not imply unreality. The conceptions which we call principles must be supposed to have reality for their cause. The study of principles is a struggle after a knowledge of reality. In the impossibility of exactness in this knowledge we seek to read the laws established for us, but we are warned to be ever on our guard against supposing them to represent things for which they do not stand.

c. A law is sometimes called a rule of conduct. Strictly speaking, the rule is derived from the law. On the other hand, a rule of conduct is called a moral law. Thus, "Thou shalt not kill" is called a law. But it is in the form of a rule, and becomes a law only when the penalty is added: "Whosoever shall kill, shall be in danger of the judgment." As the material rule does not tell where the pencil will go if it strays from the line, so a moral rule does not include the penalty of disobedience. It only directs conduct. But a moral law, fully expressed, sets forth the relations between conduct and its consequences.

d. A law is also distinguished from a principle in that a principle is a simple conception derived by analysis, while a law is the synthesis of many objects through uniform relations.

e. Principle and rule are clearly distinguished in that the principle on which a rule is based represents a relation; the rule regulates conduct in view of that relation.

f. As a rule is the limit of facility in action, and a principle the limit of discovery in perception and thought, so a law is the limit of exactness in reasoning.

6. ART, PHILOSOPHY, AND SCIENCE.-These differ from each other alike in respect to their origin, their aim, their method, and their form of statement.

a. Origin.-An art begins in the discovery of different methods of producing a given effect; philosophy, in the discovery of differences in that which has only been known previously as one; science, in the discovery of uniform relations that give a common aspect to things known before only as individual.

b. Aim. An art seeks economy of production; philosophy seeks the causes that make a thing to exist, or to be what it is; science seeks an orderly arrangement of things based on a uniformity of relations which they exhibit.

c. Method. An art is empirical; philosophy is analytical; science is synthetic.

d. Form.-An art is formulated in rules; philosophy, in principles; science, in laws.

7. GENERAL CHARACTERISTICS OF PHILOSOPHY AND SCIENCE.-Some things that belong only to Philosophy are frequently demanded of Science, and some things that belong only to Science are demanded of Philosophy. The peculiar characteristics of each should be considered in criticising the merits of any individual work, that more may not be demanded of it than properly belongs to it to do.

a. The word Philosophy, meaning the love of wisdom, is the product of Greek intelligence and enterprise, and it