The Systematic Valley (2021)

(a) just because you may fail to give a reasoned account of ethics, epistemology or aesthetics, what cause have you to believe some other rational being might not succeed? (cf the Parallel Postulate) (note also my goalpost-moving here: we already know that consistency and completeness are at odds, so it was folly to have included both in the original problem statement)

(b) the reason "nihilistic despair" is two words is because there are other endpoints to nihilism than despair. (stipulated, the "might" does imply this case analysis was supposed to be non-exhaustive, yet in that case the remainder of the argument fails to go through?)