Some science behind the scenes
Ietsism is an unspecified belief in some higher force. It is a Dutch language term (Dutch Ietsisme - "Somethingism") for a range of beliefs held by people who, on the one hand, inwardly suspect - or indeed believe - that there is “More than just the physical world, but on the other hand do not necessarily accept or subscribe to the established belief system, dogma or view of the nature of God offered by any particular religion”. The nearest English language equivalent term is Agnostic theism.
One of the better known writers who might these days be classified within this category was Olaf Stapledon.