NS,
But it isn't any different from the 'read it in a book about psychology' claim that you were defending earlier.
They're different things. Assuming that it was in a
text book (not just any old book), then there's a fair chance it would have been there as the result of research, testing, explanatory power, peer review etc. Doesn't mean that it was necessarily correct of course, but it's a reasonable, experience-based assumption that it was more
likely to be true that someone's (contradictory) intuition on the matter.
Hope on the other hand relied on some (supposed) chats with some (supposed) logicians. Assuming for now that that did happen, the evidential bar from a few chats down the Limping Whippet would be a lot lower than that for an academic text book.
That Hope may possibly made it up isn't a challenge that could be dealt with under appeal to authority. We do not really have enough information to classify this as appeal to authority.
Surely we do when that's all he gave us isn't it? "I spoke to some logicians, they agreed with me, therefore I'm right and you're wrong, please go away therefore, now about this God of mine ... etc" was the beginning and end of it.
The logicians were the authority and - well - that was it.