Many modern scholars regard belief in demons as a primitive worldview that includes elves, dragons, and a flat world. They contend that the advent of modern science, especially advances in understanding body chemistry, psychology, and neurology, enables better understanding of the phenomena the ancients attributed to the work of demons.
Skepticism about the existence of angels and demons is at odds with the direct and explicit testimony of Scripture. From the Garden of Eden in Genesis to Satan's doom in Revelation, the pages of Scripture are filled with references to evil supernatural beings who oppose God and His purposes. Their frequency of appearance actually heightens during the ministry of Jesus and the apostles. In fact, we learn most about their nature, character, and activities from Jesus and Paul.
Beside the biblical assumption of demonic reality, other matters must be considered:
Science is inherently incapable of answering this question. Some critics grant science authority to make judgments on issues it is incapable of judging. Just as science is incompetent to adjudicate on morality, so it is also beyond its jurisdiction in trying to decide the question of demonic existence. Science seeks to describe and explain natural phenomena. There is no reason to assume it has power to answer questions regarding the supernatural, such as whether these beings exist.
Purely naturalistic explanations are not adequate for describing many forms of evil in the world. Although the impact of sin on the human soul explains much of the proliferation of evil, some situations are still so abhorrent or inexplicable that they suggest a demonic origin. The horrors of an Auschwitz or of a mother roasting her own child to death imply a powerful force leading humanity to destruction.
Some therapeutic situations are best explained by the work of a spirit being. While it is true that symptoms produced by schizophrenia, dissociation, and other psychological and chemical disorders have often been wrongly attributed to demons, some conditions are best explained by the direct influence of a spirit entity. The international community of mental health professionals recognizes this and labels it "Trance and Possession Disorder," an especially common diagnosis in non-Western cultures.
We need to learn from the broader sweep of human history and cultures. The last 300 years in Western history represent the only time when the existence of evil spirits has been viewed with widespread skepticism. Furthermore, an exploration of other cultures throughout Asia, Africa, the Pacific Islands, and elsewhere reveals that belief in evil spirits continues to be integral to the worldview of many people groups.
Belief in the reality of evil spirits need not lead to uncritical or unwarranted beliefs about demons nor the bizarre and dangerous practices of extremist individuals and groups. Our task should be to integrate this more complete view of reality into our functional worldview with constant sensitivity to biblical teaching on this topic. At the beginning of the Screwtape Letters, C. S. Lewis warned that we can err in two ways as regards the devil. We can fail to take account of him or we can give him too much attention.
Extracted from the Apologetics Study Bible.