Note (return) — Chapter XI

Now that which can not move itself, but derives its motion from something else, may cease to move, and perish. "But that which is self-moved, never ceases to be active, and is also the cause of motion to all other things that are moved." And "whatever is continually active is immortal." This "self-activity is," says Plato, "the very essence and true notion of the soul." 614 Being thus essentially causative, it therefore partakes of the nature of a "principle," and it is the nature of a principle to exclude its contrary. That which is essentially self-active can never cease to be active; that which is the cause of motion and of change, can not be extinguished by the change called death. 615