When a person does terrible things that seem utterly senseless, like murder children, there is sometimes a division in the assessment of the person. Some people will take the view that the person is mentally ill on the grounds that a normal, sane person would not do something so terrible and senseless. Others take the view that the person is evil on the grounds that a normal, non-evil person would not do something so terrible and senseless. Both of these views express an attempt to explain and understand what occurred. As might be imagined, the distinction between being evil and being mentally ill is a matter of significant concern.
One key point of concern is the matter of responsibility and the correct way to respond to a person who has done something terrible. If a person acts from mental illness rather than evil, then it seems somewhat reasonable to regard them as not being accountable for the action (at least to the degree the person is ill). After all, if something terrible occurs because a person suffers from a physical illness, the person is generally not held accountable (there are, obviously, exceptions). For example, my running friend Jay told me about a situation in which a person driving on his street had an unexpected seizure. Oddly, the person’s foot stomped down on the gas pedal and the car rocketed down the street, smashing into another car and coming to a stop in someone’s back yard. The car could have easily plowed over my friend, injuring or killing him. However, since the person was not physically in control of his actions (and he had no reason to think he would have a seizure) he was not held morally accountable. That is, he did nothing wrong. If a person had intentionally tried to murder my friend with his car, then that would be seen as an evil action. Unless, perhaps, the driver was mentally ill in a way that disabled him in a way comparable to a stroke. In that case, the driver might be as “innocent” as the stroke victim.
There seem to be at least two ways that a mentally ill person might be absolved of moral responsibility (at least to the degree she is mentally ill).
First, the person might be suffering from what could be classified as perceptual and interpretative disorders. That is, they have mental defects that cause them to perceive and interpret reality incorrectly. For example, a person suffering from extreme paranoia might think that my friend Jay intends to steal his brain, even Jay has no such intention. In such a case, it seems reasonable to not regard the person as evil if he tries to harm Jay—after all, he is acting in what he thinks is legitimate self-defense rather than from a wicked motivation. In contrast, someone who wanted to kill Jay to rob his house or just for fun would be acting in an evil way. Put in general terms, mental conditions that distort a person’s perception and interpretation of reality might lead him to engage in acts of wrongful violence even though his moral reasoning might remain normal. Following Thomas Aquinas, it seems sensible to consider that such people might be following their conscience as best they can, only they have distorted information to work with in their decision making process and this distortion results from mental illness.
Second, the person might be suffering from what could be regarded as a disorder of judgment. That is, the person’s ability to engage in reasoning is damaged or defective due to a mental illness. The person might (or might not) have correct information to work with, but the processing is defective in a way that causes a person to make judgments that would be regarded as evil if made by a “normal” person. For example, a person might infer from the fact that someone is wearing a blue hat that the person should be killed.
One obvious point of concern is that “normal” people are generally bad at reasoning and commit fallacies with alarming regularity. As such, there would be a need to sort out the sort of reasoning that is merely bad reasoning from reasoning that would count as being mentally ill. One point worth considering is that bad reasoning could be fixed by education whereas a mental illness would not be fixed by learning, for example, logic.
A second obvious point of concern is discerning between mental illness as a cause of such judgments and evil as a cause of such judgments. After all, evil people can be seen as having a distorted sense of judgment in regards to value. In fact, some philosophers (such as Kant and Socrates) regard evil as a mental defect or a form of irrationality. This has some intuitive appeal—after all, people who do terrible and senseless things would certainly seem to have something wrong with them. Whether this is a moral wrongness or health wrongness is, of course, the big question here.
One of the main reasons to try to sort out the difference is figuring out whether a person should be treated (cured) or punished (which might also cure the person). As noted above, a person who did something terrible because of mental illness would (to a degree) not be accountable for the act and hence should not be punished (or the punishment should be duly tempered). For some it is tempting to claim that the choice of evil is an illusion because there is no actual free choice (that is, we do what we do because of the biochemical and electrical workings of the bodies that are us). As such, people should not be punished, rather they should be repaired. Of course, there is a certain irony in such advice: if we do not have choice, then advising us to not punish makes no sense since we will just do what we do. Of course, the person advising against punishment would presumably have no choice but to give such advice.