All real world categories have blurry borders. Tomatoes have some of the defining characteristics of both fruits and vegetables. The platypus has defining characteristics of both birds and mammals. Consequently, what we actually do is count up the defining characteristics to determine whether an item is firmly planted in the middle of the category or hovering on its fringes. The number of hairs on my head is the only thing that determines whether I am bald or not. But that does not mean that losing any single hair is going to flip the switch to move me into baldness.

Similarly a small number of good actions can’t turn a villain like Hitler into a hero, any more than the fact that I have about fifteen hairs on the top of my head can stop me from being bald. Conversely, despite the implications of articles like this one, a single bad action (or two or three) does not turn a hero into a villain. (or a non-hero, as Stephanie would probably prefer to say.) So how many does it take? That’s a complicated question. The only thing I am saying is that the answer can’t be given in a few paragraphs, which is what this article is trying to do.