The existence or nonexistence of demons is currently an interesting subject to me. I plan to write a couple of posts exploring different viewpoints on this matter.
Concerning demonology, I find myself rather disappointed with the theological material circulating throughout the church. My fear (whether warranted or not) is that this topic is possibly viewed as “embarrassing” or a “dead-end” for professional, well-trained scholars to write about. Unfortunately, much of what demonology flitters throughout Christianity is pseudo-science, conspiracy-theory, poor theology, or plain lies. On the other hand, perhaps I’ve been looking in the wrong places and missed some quality work. Feel free to drop a comment if you know about a credible scholar who has written on this subject.
I’m fascinated by the question of whether or not demons exist. If they do exist, what are they? How can we separate between fact and mythology? How would we go about researching demons? If they do not exist, then from where did this belief that spans across race and culture come? If demons do not exist, then what is the proper theological, scientific, psychological, and cultural understanding of them?
I hear similar lines of arguments from those who believe in demons. Usually, they appeal to the phenomenon of evil “spiritual forces” or a type of “dark transcendence” that is experienced by almost every culture we know of. Many cultures take the existence of these evil spirits as nearly axiomatic. Furthermore, many Christian missionaries of reputable character report encounters with demoniacs or other types of evil spirits. Of course, these are by no means definitive proofs of demons (perhaps these are cases of complex psychological phenomenon that we have yet to understand). Nonetheless, they do constitute some inductive reasons that make belief in demons more probable.
However, to many Christians, the most captivating argument for the existence of demons is the fact that Jesus believed in demons. If it is true that Jesus was known as an exorcist (which is historically certain), and if it is true that Jesus believed in demons (which is most-likely the case), aren’t we obligated to believe in demons as well? To claim that demons do not exist is to correct our savior’s theology, right? Surely, it would be arrogant (even blasphemous?) to denounce Jesus’ theology in favor of our own.
I definitely understand the appeal of this argument. I will also admit that it provides reasonable inductive rational for believing in demons. However, I do not take this argument as necessarily entailing belief in demons. It is not a knock-down proof.
I agree that it is most-definitely the case that Jesus believed in demons and was known as an exorcist. I would be quite skeptical of any historian who denied this. If this is so, how could one believe in Jesus and yet deny that demons exist? The answer lies in Christology and the incarnation. C.S. Lewis explained the matter quite poignantly:
“Now it is impossible at this point not to remember a certain sacred story which, though never included in the creeds, has been widely believed in the church […] — I mean the story that man was not the first creature to rebel against the Creator, but that some older and mightier being long since became apostate and is now the emperor of darkness and (significantly) the Lord of this world. Some people would like to reject all such elements from Our Lord’s teaching: and it might be argued that when He emptied Himself of His glory He also humbled Himself to share, as man, the current superstitions of His time. And I certainly think that Christ, in the flesh, was not omniscient — if only because a human brain could not, presumably, be the vehicle of omniscient consciousness, and to say that Our Lord’s thinking was not really conditioned by the size and shape of His brain might be to deny the real incarnation and become a Docetist. Thus, if Our Lord had committed Himself to any scientific or historical statement which we knew to be untrue, this would not disturb my faith in His deity.” 
C.S. Lewis did, however, believe in demons, but the point is an interesting one. Allow me to elaborate. The argument above does not commit one to a kenotic view of the incarnation — although, I’m sure kenoticists would be fine with the reasoning provided. Rather, it brings to light the peculiar nature of the incarnation: that Jesus had two natures — one human and one divine.
Orthodox belief teaches that Jesus was truly God and truly man. But does this not imply a contradiction? For example, God is omniscient, and humans are not. How could Jesus then possess these two, contradictory properties?
In his work on the incarnation, Timothy Pawl has given a rather captivating argument for how these apparent contradiction may be resolved — and the answer lies within the doctrine of the incarnation itself . One can affirm that Jesus is both omniscient and non-omniscient by predicating these properties over his different natures. Thus, there is not contradiction in the follow two statements:
- Jesus qua his human nature is not omniscient.
- Jesus qua his divine nature is omniscient.
Additionally, Orthodox belief maintains that Jesus was one person. However, this leaves open the possibility of Jesus having two minds . Thus, there is still debate on whether or not Christians should maintain that Jesus had two minds — one human and one divine — or only one human mind. Personally, I’m of the opinion that Jesus only had a human mind, but I’m open to changing positions.
How does this all relate to demons?
Given the above information about the incarnation, it makes perfect sense that Jesus could have certain beliefs that are false. For example, most-likely, Jesus believed the Earth is flat, that the sun revolves around a stationary Earth, and ascribed to a three-tier model of the universe. However, we know as a fact that all of those beliefs are incorrect. But because those false beliefs only apply to Jesus’ human nature and human mind, this is not a problem.
Thus, one could theoretically maintain that demons fall under a similar sphere as the flat Earth. It could be proposed that there were various psychological and neurological illness that, in Jesus’ own time, were falsely interpreted as demons. In reality, however, there are natural explanations to what was going on. Jesus and our modern sensibilities both believe in the same phenomenon, but we now have a more-complete explanation of its origins — an explanation Jesus had no access to.
Various, natural-based accounts of demonology have been proposed, but I will not here explain them all. Rather, my goal was to show that one can be an orthodox Christian and still deny the existence of demons.
Of course, this does not demonstrate that demons do not in fact exist. Usually arguments against the belief in demons are based upon the belief that the “demonic” can be given a natural explanation or that demons are part of a mythological belief system that we no longer should ascribe to.
In my next post on this topic, I will share an intriguing argument by Alexander Pruss for the existence of demons.
 C.S. Lewis, The Problem of Pain, pg. 137-138
 (Under the section titled “Incarnation”) https://plato.stanford.edu/entries/christiantheology-philosophy/#Inc