You could never prove evil. Because it's a matter of values. You could easily say, that holding negative opinions on something strongly enough that you act upo

You could never prove evil. Because it's a matter of values. You could easily say, that holding negative opinions on something strongly enough that you act upon them, without any proof of that thing being dangerous or bad is a sign you are prejudice about that thing. Now being prejudice is not evil in my opinion, but if you value being prejudice more than finding out the actual reality of your negative assumptions, makes you pretty much the text book definition of a bigot.