At this point, the concept of "evil" is a hypothesis to me because the assumptions on which it is based cannot be proven with certainty. The concept of evil requires the assumption of free will so that the person has determined their own course, and an objective standard of goodness to which people ought to ascribe. I am not ignorant of the extremes to which cruelty and destructive mentalities can reach. Cruelty cannot be justified, but there are at least some cause and effect connections that can be made based on environment and genetics. These cannot account for everything at least based on current understanding, so it also seems a theory that these factors explain the full extent of cruelty. When you view human beings as a species of animals and note examples of cruelty and kindness amongst other species, then the assumption is that everything is based on cause-and-effect. It requires many more unfounded assumptions to approach it otherwise. There is one hopeful aspect to the cause-and-effect theory for cruelty because there are ways of addressing social issues that could influence the outcome. The idea of "radical evil" can't really be controlled because it is up to the individual and this outside standard of goodness over which there is no way to influence. There is no cause-and-effect, it just exists. This intangible approach offers cruelty more power.