Harry Potter and the Methods of Rationality

Frustration was building up inside Harry. He wasn't used to being outgunned in arguments, at all, ever, let alone by a Hat that could borrow all of his own knowledge and intelligence to argue with him and could watch his thoughts as they formed. Just what kind of statistical summary do your 'feelings' come from, anyway? Do they take into account that I come from an Enlightenment culture, or were these other potential Dark Lords the children of spoiled Dark Age nobility, who didn't know squat about the historical lessons of how Lenin and Hitler actually turned out, or about the evolutionary psychology of self-delusion, or the value of self-awareness and rationality, or -

"No, of course they were not in this new reference class which you have just now constructed in such a way as to contain only yourself. And of course others have pleaded their own exceptionalism, just as you are doing now. But why is it necessary? Do you think that you are the last potential wizard of Light in the world? Why must you be the one to try for greatness, when I have advised you that you are riskier than average? Let some other, safer candidate try!"

But the prophecy...

"You don't really know that there's a prophecy. It was originally a wild guess on your part, or to be more precise, a wild joke, and McGonagall could have been reacting only to the part about the Dark Lord still being alive. You have essentially no idea of what the prophecy says or even if there is one. You're just speculating, or to put it more exactly, wishing that you have some ready-made heroic role that is your personal property."

But even if there is no prophecy, I'm the one who defeated him last time.

"That was almost certainly a wild fluke unless you seriously believe that a one-year-old child had an inherent propensity to defeat Dark Lords which has been maintained ten years later. None of this is your real reason and you know it!"

The answer to this was something that Harry would not regularly have said out loud, in conversation he would have danced around it and found some more socially palatable arguments to the same conclusion -

"You think that you are potentially the greatest who has yet lived, the strongest servant of the Light, that no other is likely to take up your wand if you lay it down."

Well... yeah, frankly. I don't usually come out and say it like that, but yeah. No point in softening it, you can read my mind anyway.

"To the extent you really believe that... you must equally believe that you could be the most terrible Dark Lord the world has ever known."