If you recall high school math, you may remember that mathematical proofs begin with axioms, propositions which are accepted as valid but unproven. These axioms are thought to be self evident. From these axioms, the student then must apply logic to build further valid propositions as proof of whatever is required or sought. Thus we see that even in the application of mathematics, which is the sacred tool and language of science, there are base assumptions which are essential but remain unproven.
If we define a belief or belief system as something we think is true in terms of correctly reflecting reality, then mathematics seemingly meets that definition. It is highly significant to realize that even something as concrete as mathematics, with its amazing power to describe physical reality, rests upon unproven assumptions. If, perchance, these basic assumptions were wrong, wouldn't that invalidate much that we believe about the physical world?
In the religious realm, especially in Christendom, correct beliefs are said to be essential. By their very nature such beliefs are unprovable, dealing as they do with the unseen and unseeable. Yet, the insistence on correct believing by Christianity means that there must be a mechanism or way to determine what is correct. If, as an extension of what I noted about mathematical proofs, we realize that the proof of essential religious beliefs must also begin with base assumptions, we face a conundrum. What are the basic assumptions, which must be accepted without proof and which then undergird the logical structure identifying the essential beliefs. If the wrong basic assumptions are made, then the resulting belief structure is automatically invalid.
Few seem to admit that, in any interpretation of the Bible, one must make basic assumptions about its message and then build on those to develop a resultant theology. The necessity of base assumptions demands that there be different possible understandings, all of which rest on unprovable assumptions. If correct belief is demanded by God, then the base assumptions must be divinely revealed, or mankind has no solid basis for determining what must be believed.
It is further noteworthy that the Bible speaks so much about faith. Faith involves a decision about what to believe. It is the very practice of selecting the base assumptions upon which we then build a belief system to govern and guide our lives. Different assumptions lead to a different faith, even when building upon the same Bible.