 Moral evil is what contemporary people—including philosophers—tend to have in mind when they talk of “evil”. Extreme forms of it are viewed by many philosophers view as “unintelligible”—as defying ordinary explanation in significant and threatening ways. Such extreme and unintelligible moral evils are what many philosophers (though not Kant) are referring to when they speak of “radical” evil (Arendt 1951; L. Russell 2014; see also  Section 7).