We shall now indicate some of the rational arguments by which it is known that everything other than Allah Most High had a beginning.

We say: One of the “arguments” by which this is known is as follows: If anything other than Allah were beginningless, it would proceed from a complete cause that necessitates its effect by its very essence and necessarily entails it, whether or not that cause is held to possess will or choice. For a beginningless, eternal contingent being, which does not exist independently, cannot conceivably exist unless there is, from all eternity, a complete cause necessarily entailing its existence.

Not only is this known by rational necessity, but rational thinkers do not dispute it. No one says that a beginningless, eternal being proceeds from an agent whose effect does not necessarily accompany it. Nor does anyone say that it proceeds from an incomplete cause necessitating something other than its own effect; or from a cause that necessitates by its very essence, yet is not accompanied by what it necessitates and brings about; or from an agent acting by choice whose effect may be delayed.

For if its effect could be delayed, then it would be possible for that beginningless, eternal being to be beginningless and eternal. Its existence from all eternity would thus be contingent, while nothing would exist from all eternity to necessitate that existence. Its existence from all eternity would therefore be impossible. For the existence of an eternal contingent being without a complete cause necessarily entailing it is impossible by rational necessity. Plain reason establishes that no contingent being exists unless the complete cause necessarily entailing its existence obtains.