Ietsism is a Dutch term for a range of beliefs held by people who, on believe that “there must be something undefined beyond the material and that which can be known or can be proven”, but on the other hand do not necessarily accept or subscribe to the established belief system, theology or view of the nature of a God offered by any particular religion.
The name derives from the Dutch equivalent of the question: “Do you believe in the conventional ‘Christian‘ God?”, a typical ietsist answer being “No, but there must be something”, “something” being iets in Dutch.
This is a philosophy which postulates that there is one underlying theological truth, of which all religions express a partial understanding, and as to which “the devout in the various great world religions are in fact worshiping that one being or Source, but through different, overlapping concepts or metaphors.
Dutch biologist Ronald Plasterk
A poll from 2004 showed that as much as 40% of the Dutch population could be considered ietsist, and other European countries would probably get similar rates. Hence labeling ietsists as either religious or nonreligious could tilt the demographic balance for those countries to either predominantly religious or predominantly nonreligious!