It is inconceivable that an effect should be anything other than the reappearance in a different form of the exact quantity of energy that caused it; for if the energy of the effect exceeded that of its cause, then part of the effect would have been produced without cause; and if the energy of the effect fell short of that of the cause, then part of the energy of the cause would have been expended without producing an effect. That, however, would be the negation of causation, it would be an admission that part of the effect (i.e. an effect) could be produced without sufficient cause, i.e. out of nothing, and that a part of the cause (i.e. energy) could disappear (into nothing) without producing an equivalent effect, which is obviously absurd. The human Will manifests itself by an action or the prevention of an action according to the impulse felt by our organism. Both these are an exercise of force, the amount of which can be measured. Indeed, inhibition, too, is a dynamical effort which represents the exact equivalent of the force with which the impulse which it has checked acted on the motory centres. The Will, therefore, expends energy which does work that can be measured. But the Will must derive this energy from some source. It therefore also only converts energy derived from the energy of the universe, the total amount of which can neither be augmented nor diminished; the Will consequently is a part of the dynamic energy of the universe, and must necessarily be subject to its mechanical law; that is, to the law of causation. It is therefore not free, but dependent, as is every phenomenon in the universe. Whoever maintains its freedom maintains that it is independent, that it is not subject to the law of causation, that it has no cause of which the elements, if they could be fully known to us, would be measurable, that it expends energy which it derives from nowhere, that it produces energy out of nothing. Whoever maintains this contradicts all experience from which the knowledge of Nature and her laws has been built up; it is obviously hopeless to expect a reasonable discussion with such a person.