hension of natural principles or natural laws. A natural principle or natural law is an identity observable in nature, a discovered or discoverable sameness in the ways in which natural objects behave, or in the relations obtaining between certain objects. Thus a law of mechanics is an ascertainable identity in the way physical objects move or tend to move. The law of gravitation is a well-known example. This law is nothing but the fact that material bodies move or tend to move toward each other in a similar way, a way capable of description in the Newtonian formula: "Every particle of matter in the universe attracts every other particle with a force directly proportional to the mass of the attracting particles, and inversely to the square of the distance between them." So far as we know, every particle of matter might repel instead of attract every other particle of matter. And even if it did attract, it might attract in, say, inverse proportion to the distance instead of to the square of the distance between them. The number of possible substitutes for the actually obtaining law of gravitation is beyond recounting. The Newtonian law given above is the law only because it is the law. But though the law does not carry with it a self-evidence which excludes all possible rivals, as a matter of fact it satisfactorily explains many things otherwise inexplicable to our intelligence. We are so constituted that we do not find intellectual rest until the initial disjointedness of experience is removed by the discovery of uniformities of relations and of behavior in experienced objects. Any such discovery which brings order into what was chaos is highly gratifying to us as rational beings, for our theoretical reason is a tendency—of the nature of instinct—to look for such uniformities, and to see things in relations. Any object is 'explained' when this instinct is gratified. Now it would carry us too far afield to prove this statement in detail, i. e., to show that in all explanation this is what happens. The exhibition of this fact belongs to the science of logic or epistemology. Here all that can be done is to state dogmatically that explanation is the satisfaction of the intellectual instinct to comprehend the laws of things, or their principles, or the uniformities of their relation and behavior,—these expressions all meaning the same thing.
