Well, at 12 Int and 7 Wis I'd typically say that most people would meet with more success if they put less stock in logic and more in intuition, inspiration, and spontaneity, because logic is inherently timid and fortune fawns for the brave, however, in the context of the broader conversation (as in some other contexts) I'd instead feel and say that by definition there's no good argument against "behaving logically," a phrase by which I mean doing whatever is most effective in pursuit of your aims while keeping within the constraint of pretending that the only things that matter to you are self-preservation and personal comfort and the number in your bank account, unless doing whatever is most effective in pursuit of your aims would require you to recognize that you and/or other people have emotions, in which case you should do whatever would be the most effective if only that weren't true. This isn't my considered position, to be clear, but it's what I think Aberian's is, which in my 12/7 mind is of a kind with being logical, and of course you can't directly argue against "logic" right after using the word as a synonym for "good idea," as that'd be too obviously self-defeating.
If you boosted my Int to 19 and my Wis to 14 I'd still have plenty of deranged ideas about what constitutes "logic" and why it's situationally good or bad to possess (mostly bad, tbh, since there's no logical reason to like full plate), and I definitely wouldn't be so advanced along the path as to tell you that ultimate goals cannot themselves be logical or illogical and that reason is cause-agnostic, and after a rough spot of trying to be reasonable about everything when my Int and Wis have outgrown my outmoded conception of "reason," I'd have found the escape hatch and moved further towards relying on illogical intuition, but at least I'd be past confusing myself by conflating "a good idea [something I want to do]" with "a good idea [something you could explain to someone else why you'd like to do it]" and "something my father said [generally a good idea]" and other neighboring concepts.
In answer to your question of what a "good idea" is, I'd probably say something like that a good idea is hard to define in the abstract and that any attempted definition would be easy to find edge-cases in, but that I can point at the general category and I think it's a natural enough category that you ought to be able to see it if someone's pointing at it, and that the category I'm pointing at are those ideas which serve to increase your options and abilities and life satisfaction, where life satisfaction is broader than just happiness but includes happiness as an important component.
If you'd somehow gotten it into your head to be a Kuthite, I hope you can see how if someone told you that you should do things that make you happier, and if you said you didn't want to be happy, the correct response would be that you should start wanting to be happy. It's the same exact thing if you say that you're an Erastilian and think you'd rather do your duty than be happy, or if you're a Sarenite and think you'd rather make others happy than be happy. To be clear, there's nothing wrong with doing your duty or with making people happy, if those are what make you happy, and I'm a big fan of both, but I do them because it pleases me to and I don't bother when it wouldn't.