Evil is a religious concept that originated with the Christian perspective. There is no proof that "evil" or evil as an entity actually exists in reality. The belief that evil could possess humans comes from superstition and religious teaching. It gave Egyptian priests and the church fathers a lot of power over people and that power was justified on the basis that they had a special power of exorcism. Even though we have disposed of the notion that "evil" as a thing exists or evil possession is a problem. The problem is mental illness but we will have to contend with those who have the most to gain from the point of view that "evil" represent a "spiritual" problem, to wit, the clergy.
Bertrand Russell said, "It is possible that mankind is on the threshold of a golden age; but, if so, it will be necessary first to slay the dragon that guards the door, and this dragon is religion."
Written documents that identify Schizophrenia can be traced to Egypt during the Old Kingdom, and long before the Christian Era. Depression, dementia, and schizophrenia are described in detail in the Book of Hearts. The ancient Egyptians did not understand that the heart had nothing to do with rational thinking. They thought that mental illness came from maladies of the heart, uterus or demons. Throughout most of human history people didn't locate their thoughts and emotions within the brain. The same idea that the heart and other organs are involved with our thinking process can be found in the Scriptures. Historians agree that for thousands of years the heart, rather than the brain, was recognized as the most important organ in the body. Many things found in the bible come from ancient Egypt (The Ten Commandments came from the Egyptian Book of the Dead).
The nonspecific concept of madness was around for many thousands of years but there was no scientific research (the reason for mental illness was not known). Early theories presumed that mental disorders were caused by evil possession of the body, and the appropriate treatment was exorcising these demons, sometimes by exposing the afflicted person to dangerous and deadly methods. Mental illness does exist; evil doesn't, and in some cases the mental illness produces abhorrent, violent and dangerous behavior. The ancient Greeks and Romans literature indicates that the general population had an awareness of psychotic disorders, but they could not properly diagnose or treat mental illness. The word schizophrenia comes from the Greek roots (schizo and phrene) to describe the fragmented thinking of people with the disorder. The word schizophrenia was identified as a mental illness in the late1800's but it has occurred within humanity throughout its history. Schizophrenia is a biologically based disease of the brain. This is supported by dynamic brain imaging systems that show very precisely the wave of tissue destruction that takes place in the brain of schizophrenics. There have been huge advances in genetics that would make it possible for far more effective therapies and even cures, but the mentally ill have to be identified, and what would produce the best outcome for society and the patient would be diagnosis and treatment at the earliest stages. That is not (in my opinion) happening because of the presumption of evil. People who do not feel bad about doing wrong could be sociopath or psychopath. Sociopath can exist in many different forms and degrees; not all of them are dangerous, but psychopath is a serious and dangerous illness. Many of them should never be lose in the public until we find some answers.
Psychopathic behavior can be identified at an early stage. Knowledge in this area has come awfully slowly and that is due to a lot of superstitious bologna getting in the way of progress. Our survival as the human race may well depend upon what happens in the future. That is why we should be allowed to teach our view of things; by exposing the fallacies, giving the actual facts in contrast to biblical "wisdom" or just stating assumptions, that is what would be very beneficial. Instead of dealing with a so-called "evil" that never existed in the first place by methods that have been proven to fail. Neither religion nor punishment is an effective way to deal with mental illness.
