A new approach to developing models of folk psychology is suggested, namely that different models exist for different folk psychological practices. This point is made through an example: the explanation and justification of morally heinous actions. Human folk psychology in this area is prone to a specific error of conflating an explanation for behaviour with a justification of it. An analysis of the error leads me to conclude that simulation is used to generate both explanations and justifications of heinous acts. It is needed in both these cases because most of us lack theoretical information about evil actors. I will argue that it is difficult to simulate such acts, and hence difficult to develop explanations for behaviour widely accepted...