Sir Humphry Davy led wandering lecturers and all sorts of sciolists to affirm that they could explain all things, matter and mind itself, by electricity. So, in these days, development, having furnished a key to open so many of the secrets of Nature, has led some to imagine that it can solve all the mysteries of the universe. Some of us may be inclined to admit, and to use for scientific purposes, the doctrine of development, and yet be prepared to deny that it can explain everything. The fact is, it overlooks a great many more things than it notices. There are signs of a reaction among scientific men against its extreme positions; and it is the work of the age now present to show how much development can do, and how much it cannot do. Even Darwin is obliged to call in a few germs created by God, and a pangenesis in order to account for development. Herbert Spencer acknowledges a great Unknown behind visible phenomena. Huxley recommends a worship chiefly "of the silent sort." Religion comes to them and says, "Whom, therefore, ye ignorantly worship him declare I unto you."
In the common apprehension of those who hold the development hypothesis, all that is necessary to account for the world in its present state is to suppose that millions of years ago there appeared—no one can tell how—a nebulous mass with an inconceivably high temperature, but losing its heat and ready to condense; that in the long lapse of time it took the shape of planets, satellites, and sun; and that on one of these planets—that on which we dwell—it formed into plants, animals, and finally man, all by its own power, according to natural law, or, rather, the necessity of things, without it being necessary to call in a God or a guiding providence, or to suppose that there has been a plan in a designing mind. All the defenders of the theory do not state this in express words, but it is the impression left by their expositions, though some of them, such as Herbert Spencer and Tyndall, would save themselves from the blank consequences by calling in an unknown and unknowable power beyond the visible phenomena, or by appealing to some religious feelings supposed to be deep in our nature, but which the theory would soon undermine, as being, in fact, unjustifiable and unreasonable. This is the view that I mean to meet. In examining this hypothesis there are some things which I am willing to admit as being established truths:
1. I hold the doctrine of the Conservation of Force—that is, that the sum of energy, real and potential, in the universe is always one and the same, and cannot be increased or diminished by human or mundane action. I was prepared for this doctrine when it was announced by Mayer, of Heilbronn, and by Joule, of Manchester, and expounded by Grove, of London. It seemed to me to follow from the doctrine which I had laid down in my first work—"The Method of Divine Government"—published twenty-six years ago: as to the material universe being composed of substances with properties or pow-
