Assuming, from the title, that you’re looking for argument by counterexample...
The obvious reply would be to invoke Godwin’s Law—there’s a quote in Mein Kampf along the lines of “I am convinced that by fighting off the Jews, I am doing the work of our creator...”. Comments like this pretty reliably generate a response something like “Hitler was a diseased mind/insane/evil!” to which you may reply “Yeah, but he was pretty sharp, too.” However, this has the downside of invoking Nazis, which in a certain kind of person may provoke an instant “This is a reactionary idiot” response and a complete discarding of the argument. So it’s a temperamental trick, and I’m not skilled enough in the dark arts to know if it’s a net gain.
On the other hand, you might prefer Pol Pat, or Ted Bundy, or any of a very large number of dictators and serial killers who don’t produce the same mindkilling response as Hitler.
A lot of fictional evidence comes to mind as well, but we do try not to generalize from that… Still, if you just want to WIN the argument rather than win rationally, it may help to pull an example from some media form that the audience is likely to appreciate. Lex Luthor, Snidely Whiplash, Yagami Light (or L, if you prefer), Mephistopheles (or Faust), and so on.
Eh… I can’t think of any object-level fact that would have convinced Hitler that the Judeo-Christian memeplex, most clearly manifested in the Jews, wasn’t actually a serious threat to the (prospective) virility & Spartan glory of Germany.
Assuming, from the title, that you’re looking for argument by counterexample...
The obvious reply would be to invoke Godwin’s Law—there’s a quote in Mein Kampf along the lines of “I am convinced that by fighting off the Jews, I am doing the work of our creator...”. Comments like this pretty reliably generate a response something like “Hitler was a diseased mind/insane/evil!” to which you may reply “Yeah, but he was pretty sharp, too.” However, this has the downside of invoking Nazis, which in a certain kind of person may provoke an instant “This is a reactionary idiot” response and a complete discarding of the argument. So it’s a temperamental trick, and I’m not skilled enough in the dark arts to know if it’s a net gain.
On the other hand, you might prefer Pol Pat, or Ted Bundy, or any of a very large number of dictators and serial killers who don’t produce the same mindkilling response as Hitler.
A lot of fictional evidence comes to mind as well, but we do try not to generalize from that… Still, if you just want to WIN the argument rather than win rationally, it may help to pull an example from some media form that the audience is likely to appreciate. Lex Luthor, Snidely Whiplash, Yagami Light (or L, if you prefer), Mephistopheles (or Faust), and so on.
Is that the sort of thing you wanted?
Hitler also had a lot of false beliefs about Jews.
Eh… I can’t think of any object-level fact that would have convinced Hitler that the Judeo-Christian memeplex, most clearly manifested in the Jews, wasn’t actually a serious threat to the (prospective) virility & Spartan glory of Germany.