Fourth, we say: Voluntary motion is a perfection in a thing, like life and similar attributes. If we suppose two entities, one moving by its own choice and the other not moving at all, the first is more perfect.

The opponent says:
“Fourth: To his question, ‘Why may He not be moving?’, your answer is, ‘Motion has a beginning.’”

I reply:
“Does motion as a kind have a beginning, or do its individual instances? The former is denied; the latter is conceded. As for your statement, ‘Whatever is never free of events that begin in time must itself have a beginning,’ if you mean whatever is never free of such events as a kind, this is denied; the second interpretation does not undermine our position. You have offered only one argument for motion as a kind having a beginning: your statement, ‘What has a beginning cannot be eternal without beginning.’ This argument is weak, as has already been explained.”

For the expression “what has a beginning” may refer either to a kind or to an individual instance, and is therefore ambiguous. Likewise, the statement “What perishes cannot endure” is ambiguous. If the speaker means that what exists in its own right cannot endure, this is true. But if he means that something whose individual instances perish cannot endure as a kind, this is false. The bliss of Paradise is perpetual and enduring, although every act of eating, drinking, sexual intercourse, and other movements passes away, one after another, while their kind does not perish.

As for his statement in the second argument:
“The fact that He occupies His particular space must be due either to His essence or to something external that determines it.”