Question

Seemingly, Rabbi, a person who is a determinist and denies free choice can indeed arrive objectively at the conclusion that he is deterministic, can he not? That does not fall under the claim that a determinist is sawing off the branch he is sitting on.
The only thing is that he will never be able to justify it, because any justification is circular. But for the one who claims this, it would indeed remain an objective reality (from his perspective).