16. (Creation of Matter.)—It may perhaps be urged, as an objection to this doctrine, that it asserts Matter to be a necessary constituent of the universe, and thus involves the assertion of the eternity of Matter. But in reality the doctrine asserts Matter to be eternal, only in the way in which time and space are eternal. Whether we hold that there was a creation before which time and space did not exist,—with the poet who says
Ere Time and Space were Time and Space were not,—
is not essential to our present inquiry. Certainly we cannot conceive such a state, and therefore cannot reason about it. We have no occasion here to speak of Creation, nor have spoken of it. What I have said is, that Space and Time, Force and Matter are universal elements, principles, constituents, of the universe as it is—and necessary Ideas of the human mind existing in that universe. If there ever was a Creation before which Matter did not exist, it was a Creation before which Force did not exist. And in the universe as it is, the two are necessarily co-existent in the human thought because they are co-existent in the Divine Thought which makes the world.
We apply then to Force and Matter the doctrine—the Platonic doctrine, if any one please so to call it,—that the world is constituted according to the Ideas of the Divine Mind, and that the human mind apprehends the inward and most fundamental relations of the universe by sharing in some measure of those same Ideas.
17. (Platonic Ideas.)—But do we go on with Plato to extend this doctrine of Ideas to all the objects and all the aspects of objects which constitute the material universe? Do we say with Plato that there is not only an Idea of a Triangle by conformity to which a figure is a triangle, but an Idea of Gold, by conformity to which a thing is gold, and Idea of a Table, by conformity to which a thing is a table?
We say none of these things. We say nothing which at all approaches to them. We do not say that there is an Idea of a Triangle, the archetype of all triangles; we only say that man has an Idea of Space, which is an Idea of a fundamental reality; and that therefore from this Idea flow real and universal truths—about triangles and other figures. Still less do we say that we have an archetypal Idea of Gold, or of a Metal in general, or of any of the kinds of objects which exist in the world. Here we part company with Plato altogether.
But have we any Ideas at all with regard to objects which we thus speak of as separable into Kinds? We can have knowledge,—even exact and general knowledge, that is, science—with regard to such things—with regard to plants and metals—gold and iron. Do we possess in our minds, with regard to those objects, any Ideas, any universal principles, such as we possess with regard to geometrical figures or mechanical actions? And if so, are those human Ideas verified in the universe, as the Ideas hitherto considered are? and do they thus afford us further examples of Ideas in the human mind which are also Ideas in the Divine Mind, manifested in the constitution of the universe?
18. (Idea of Kinds.)—We answer Yes to these questions, on this ground:—the objects that exist in the world, plants and metals, gold and iron, for example, in order that they may be objects with regard to which we can have any knowledge, must be objects of distinct and definite thought. Plant must differ from metal, gold from iron, in order that we may know anything at all about any of these objects. The differences by which such objects differ need not necessarily be expressed by definitions, as the difference of a triangle and a square are expressed; but there must manifestly be fixed and definite differences, in order that we may have any knowledge about them. These Kinds of things must be so far distinct and definite, as to be objects of distinct and definite thought. The Kinds of natural objects must differ, and we must think of things as of different Kinds, in order that we may know anything about natural objects. Living in a world in which we exercise our Intellect upon the natural objects which surround us, we must regard them as distinct from each other in Kind. We must have an Idea of Kinds of natural objects.
19. The Idea of a Kind involves this principle: That where the Kind differs the Properties may differ, but so far as the Kind is the same the Properties contemplated in framing the notion of each Kind are the same. Gold cannot have the distinctive properties of Iron without being Iron.
In the case of human knowledge, each Kind is marked by a word—a name; and the doctrine that the notion of the Kind must be so applied that this same Kind of object shall have the same properties, has been otherwise expressed by saying that Names must be so applied that general propositions may be possible. We must so apply the name of Gold that we may be able to say, gold has a specific gravity of a certain amount and is ductile in a certain degree.