One key aspect of Christadelphian theology which helps explain it is the denial of many supernatural elements in scripture that most of mainstream Christianity believes. Man to them is a physical being. He doesn’t have an immaterial soul or spirit. Neither does God also for that matter. Nor is there a devil. This simply refers to “sin in the flesh.” Nor are there demons. This simply refers to mental illness, epilepsy and other disorders.
The claim of the founder, John Thomas, was that these beliefs were superstitions which had found their way into people’s minds as a result of paganism creeping in.
Today, many liberal Christians would share his disbelief, but with a difference. They accept fully that the writers believed in these things, but they also believe God inspired within the times in which they lived. Christadelphians historically have not followed or follow that position, but believe scripture to be infallibly inspired and therefore accurate in every way including scientifically. To the Christadelphians the first century Christians didn’t believe in the devil, demons, spirits and so forth because historically and in line with their statements of faith such beliefs ruin a person’s chances of salvation. Many liberal Christians would accept they did, but don’t themselves. To most Christadelphians “not believing” is a fellowship and salvation matter.
It is generally maintained this position was a restoration of first century Christianity despite the lack of history of others sharing that view and the common way passages in the Bible were previously understood.There are lots of resources below looking at this, but a big practical difficulty with this position is that it severely complicates the reading of many passages, particularly in the New Testament. The book of Mark for instance is full of references to demons. We may read into passages that say "Jesus cast out demons", “Jesus cast out mental illness” or “Jesus cast out epilepsy” but that’s not what it says. Nor is it what the writers seemed to believe and if God wrote infallibly through them it doesn’t seem he believed that either. To do that requires at the very least a change of understanding of the way in which God inspired people.
The untenable nature of the historical Christadelphian position was noted by George McHaffie (a Christadelphian) in a booklet he wrote called “Christadelphia ”:
With regard to the Devil, our contention that the Bible teaches this to be flesh or human nature “in its various manifestations” will simply not match up to Eph. 6:11, 12. “... stand against the wiles of the devil. For we wrestle not against flesh and blood... but... spiritual wickedness in high places.” The repeated references to the devil, the power of demons, and their being exorcised without any statement that there is no devil and demons or even an “as is supposed” in reference to a demon would carry conviction to most people that the Bible writers believed in the devil and demons. Supposing they did: would they have written in differently?
Yet it seems beyond question that the phenomena once thought to be the work of demons etc., are more rationally explicable on other grounds. The only explanation of all this seems to be as already outlined under “Fundamentalism” that the Bible contains references to contemporary beliefs on many things incidental to the main intention of revelation. It would make our witness much more frank if we could acknowledge this primitive element rather than endeavour to build up a case to show that it is not actually in the Bible at all. This carries with it, also, the implication that if anyone, out of conviction, believes in the devil and demons, he is nevertheless acceptable to God providing his behaviour is otherwise Christian.
To most Christadelphians the views here are heretical, because he suggests a significantly different view of Biblical inspiration which carries implications that are far reaching potentially on many other areas of Christadelphian theology if widely embraced. The discussion of such views of inspiration were in fact why a Foundation Statement was added to the main Statement of Faith historically and the idea has been called by Christadelphians “partial inspiration.”
The interesting statement here which may in fact reflect the true origins of Christadelphian beliefs is the phrase, “it seems beyond question that the phenomena once thought to be the work of demons etc., are more rationally explicable on other grounds.” The counterclaim when John Thomas was alive was that his thinking was influenced by the growing advent of science and the effects of the period which is now called “The Age of Enlightenment.” This also explains why the beliefs of mainstream Christianity are moving in the Christadelphian direction too. Quite simply scripture is being reinterpreted to fit a more rational and less supernatural view of the world.
It is interesting to note that an honest recognition of the non literal reinterpretations of many passages is acknowledged now by a few Christadelphians who wish the community to adopt evolution as well and are pressing more openly for a reconsideration of how inspiration works. This is consistent with the methodology that was behind the formation of the community, even though that influence historically has been denied. An interesting idea posited by one Christadelphian is that God has two words, (the physical world and the Bible) and the two are assumed to be in harmony and have to be balanced.
The appeal of the Christadelphians is partly therefore that of being a more rational, more logical religion. This appeal was also recognised by a sociologist, Bryan Wilson, in “Sects and Society” where he writes, “In some ways Christadelphianism reduces the element of the supernatural in orthodox belief and posits a very much more mundane order, with an anthropomorphic conception of the Deity and the life hereafter, and this might help to account for its appeal to persons who had found orthodox religion of no consequence to them, or as beyond their conception or credulity.
The major difficulty here is that to maintain the belief in rigid scriptural infallibility whilst using scriptures written by people who didn’t have a philosophy of materialism requires very complex explanations to various passages that could be explained far more simply. It makes the Bible a very complex book to read and understand and for outsiders they have to grasp the internal forms of logic and interpretation followed.
For those who leave this is an important issue too because incredulity is frequently attached to mainstream Christian beliefs and they are ridiculed in with line with modern scientific thoughts and worldviews.