invalid. How much more so if he says, “If a moving thing itself produces its own motion, then what is nonexistent must produce itself”? Rather, an agent can produce something other than itself, but it cannot produce itself. If he were to say, “If a moving thing produces motion, then what is nonexistent must produce motion,” this would be false. How much more so if he says that it must produce itself!

He says: “Every existent that was not at one time existent potentially and at another actually exists of itself. A moving thing exists only together with the moving force; hence every moving thing requires a mover.”

He should be answered: “Suppose we grant you that a moving thing exists together with the moving force. Why, then, do you say that motion requires a mover separate from it?”

You should then be asked: “Can a moving thing move by itself after not having been in motion, or not?”

If you allow this, your claim is invalidated, and the moving thing may exist of itself before motion and before the moving force. If you say that this is impossible, you should be told: “Its motion must then come either from itself or from something else. If it comes from itself, the motion comes from the moving thing itself, and your claim is invalidated. If it comes from something else, and that other thing is moving, then the argument