The point here is that a contingent being cannot come to exist without a determining cause, and that rational people agree on this. Allah knows best.

[Section]

Despite following the approach discussed above, al-Rāzī stated that this premise—namely, that neither of the two alternatives concerning a contingent being can prevail over the other without a determining cause—is self-evident. He also stated that anyone whose position entails something contrary to it does not himself accept that consequence. Thus, no rational person embraces its opposite, and positions that entail the opposite of this proposition are certainly false.

What he says is correct regarding what is known to be contingent, namely, that which comes into existence. For reason necessarily recognizes the impossibility of something coming into existence without anyone bringing it about. As for the contingent in the sense they give it—a sense that encompasses what is eternal—he shows that this is invalid, and that by this method they have established neither a mutamakkin nor a necessary being.

He also stated, however, that reason necessarily recognizes that, where two alternatives are equally possible, neither can prevail over the other without a determining cause.

This is correct, and rational people generally agree with him on it.