By Credo Quia Absurdum
Christadelphians have sought to portray themselves as "A religion that makes sense" - as the old tract has it. In doing so they reject much of what mainstream Christianity includes, such as belief in the existence of malevolent supernatural forces - which certainly makes sense in the modern scientific world. And they go considerably further than the biblical authors who clearly understood that there were demons amongst the evil supernatural beings that were opposed to god.
I think it can all be explained with reference to the development of religion in primitive humans. Without any real insight into what caused things to happen around them - the sunrise, the winds, the rain, the rivers, the natural disasters, they ascribed agency to them. Conscious but unseen beings must be responsible for everything that happens; and so they had a poly- or even pantheistic view of nature. But as human beings became more sophisticated and learned how the world and nature really worked, they understood that there was no need for explanations other than the natural processes, and so the number of gods decreased.
Some things are difficult to understand.
Disease and death are the most fearful threats. Disease was still seen as a punishment or a demon possession until relatively recently in human history. Anyone who has witnessed a person having an epileptic fit will know that they do indeed seem to be "possessed". You can talk to them and they may respond, but it is clear that they are not responding as themselves and they will have no memory of what they said.
Survival beyond death is a hope fostered by our dreams of lost loved ones; and who hasn't experienced that? And our desire to consult them for their wisdom in imagined conversations is most likely the origin of prayer.
But as scientific knowledge has increased humankind has done away with most of the supernatural beings, and Christadelphians have done away with the devil and demons and some of the silliest of the supernatural explanations. But somehow they cling to a belief in one god, who created a vast universe of unimaginable dimensions, in which he is particularly fond of an area that occupies about 0.014% of the landmass of a particular rock that revolves around one of upwards of 200 billion other stars in our galaxy, which is among more than 200 billion other galaxies in the vastness of the universe. With this relatively recent knowledge of how insignificant we really are it is mind-boggling that any serious thinking person cannot see that the whole religious edifice is wishful thinking, left over from the primitive ignorance of humankind.
As Christopher Hitchens says:
"Religion comes from the period of human prehistory where nobody...had the smallest idea what was going on. It comes from the bawling and fearful infancy of our species, and is a babyish attempt to meet our inescapable demand for knowledge (as well as for comfort, reassurance and other infantile needs). Today the least educated of my children knows much more about the natural order than any of the founders of religion..."