The ultimacy and decisiveness of reason is itself just as vulnerable as the existence of God. That one ought to “justify” one’s thought is to me just another religious-like commandment. If someone does not buy into the god-level authority of reason, especially pertaining to universal and ultimate domains of predication themselves, there is no possible logically prior inferential warrant.
Only assuming logic and reason makes logical priority possible and necessary, so there is nothing possibly logically prior, in the sense of more inferentially basic, if logic itself is questioned. One can end up *appealling* to some kind of pragmatics of intellectuality, but that’s not a logical appeal unless it is simply begging the question all over again: namely, whether logic or general reason have any god-like authority over one’s thinking, and this is just as questionable in any other proposed authority, hardly limited to the God belief.
These points and any other possible points that I am making in this writing are themselves subject to the same problems, since they too depend on a wholesale acceptance of some core of a logical/rational ideal, nonlocal obligation relations between rational standards and each mind, the preferential value of inquiry, reason, etc.
But at that level what can be argued against them, and what need is there to justify them?