a subject, this is true. But this does not entail that it depends on an agent, or that the subject depends on an agent.
Thus, his statement, “If it is the latter, necessity would be possible, and what is characterized by it would have all the more reason to be possible,” is a fallacy. For the possibility attributed to necessity consists only in its dependence on a subject, not on an agent.
Clearly, if an attribute depends on that which possesses it because it is its subject, not its agent, it does not follow that what possesses the attribute has all the more reason to be a subject. Even if necessity were assumed to depend on a distinguishing factor other than its subject, this would be the dependence of a condition on what it conditions, and of a necessary concomitant on its correlate—not the dependence of an effect on an efficient cause.
Such dependence is not incompatible with the necessity of existence; indeed, the necessity of existence cannot dispense with these relations. For the necessity of existence is not itself the necessary existent, but an attribute of it. Moreover, the necessary existent has things that it necessarily entails and things that necessarily entail it, yet this does not entail its dependence on a causal agent. All the more, then, necessity does not depend on a causal agent merely because of what it necessarily entails and what necessarily entails it.
These, then, are two lines of argument other than those he and others like him have mentioned here.