In the same way we seem forced to think of life, vitality, as an entity--a fact as real as electricity or light, though it may be only a mode of motion. It may be of physico-chemical origin, as much so as heat, or light; and yet it is something as distinctive as they are among material things, and is involved in the same mystery. Is magnetism or gravitation a real thing? or, in the moral world, is love, charity, or consciousness itself? The world seems to be run by nonentities. Heat, light, life, seem nonentities. That which organizes the different parts or organs of the human body into a unit, and makes of the many organs one organism, is a nonentity. That which makes an oak an oak, and a pine a pine, is a nonentity. That which makes a sheep a sheep, and an ox an ox, is to science a nonentity. To physical science the soul is a nonentity. There is something in the cells of the muscles that makes them contract, and in the cells of the heart that makes it beat; that something is not active in the other cells of the body. But it is a nonentity. The body is a machine and a laboratory combined, but that which cooerdinates them and makes them work together--what is that? Another nonentity. That which distinguishes a living machine from a dead machine, science has no name for, except molecular attraction and repulsion, and these are names merely; they are nonentities. Is there not molecular attraction and repulsion in a steam-engine also? And yet it is not alive. What has to supplement the mechanical and the chemical to make matter alive? We have no name for it but the vital, be it an entity or a nonentity. We have no name for a flash of lightning but electricity, be it an entity or a nonentity. We have no name for that which distinguishes a man from a brute, but mind, soul, be it an entity or a nonentity. We have no name for that which distinguishes the organic from the inorganic but vitality, be it an entity or a nonentity. VII Without metaphysics we can do nothing; without mental concepts, where are we? Natural selection is as much a metaphysical phrase as is consciousness, or the subjective and the objective. Natural selection is not an entity, it is a name for what we conceive of as a process. It is natural rejection as well. The vital principle is a metaphysical concept; so is instinct; so is reason; so is the soul; so is God. Many of our concepts have been wrong. The concept of witches, of disease as the work of evil spirits, of famine and pestilence as the visitation of the wrath of God, and the like, were unfounded. Science sets us right about all such matters. It corrects our philosophy, but it cannot dispense with the philosophical attitude of mind. The philosophical must supplement the experimental.