The concept you need to look further into is referred to as "first principles".
The fact is that what you've said here is mostly correct except that those who do theology properly don't permit this situation to persist all the way down to their most foundational presuppositions. In other words, our premises and biases are based on something more substantial than mere personal opinion or a desire to maintain a particular belief system. You have to build you doctrine on a solid foundation that is far more substantial than blind belief and personal opinions.
Since I was a child, I have been passionately interested in answering the question, "Why do 'they' believe what they believe?". My family drove past a dozen or more churches on the way to the church we attended and I was constantly asking things like, "What do they believe that's different than what we believe?". I remember once that I naively told my mom that, "We sure are lucky that we found the right church to go to!". I bet I wasn't even ten years old when I said that. The point being, that I have literally spent my entire life paying attention not only to what various Christians believe but why they believe it and I have never been so married to a particular belief that I was unwilling to drop it in order to pick up a doctrine that I felt was better supported by the plain reading of scripture and sound reason. My loyalty has always been to the truth, not to a denomination, group or person. I have, over the years, held to dozens and dozens of doctrines that I no longer hold to. I was literally the poster child for being blown about by every wind of doctrine! The thing I'm most embarrassed about having ever given any credence to is a toss up between charismatic "speaking in tongues" (complete insanity) and the World Wide Church of God (kookoo bird insanity on the verge of being a cult). Needless to say, neither of those lasted long because while they might have an initial appeal, neither can really stand up to the sort of honest scrutiny that I was willing to pay attention to and permit to persuade my mind.
In fact, the only thing that ever stuck for longer than a few years was the system of theology that I hold to today and that I have held to now for more than two decades (almost three actually - wow!). The reason it has such sticking power is precisely because it is NOT an interpretation of the bible that "depends entirely on what premise or bias they begin with", as you put it, with the exception, of course, of a handful of first principles, like the fact that God exists; that God is living, personal, righteous, loving and just; that the bible is literally true and as such it should be taken to mean what it seems to mean whenever possible, and some other similar type things. And, indeed, as a write this I realize that even most of those things are logically defensible positions that are not simply presupposed and believed in an a priori manner.
So far as I am aware, and I wrote all the above to lend credence to the fact that I am pretty well aware of most flavors of Christianity, there isn't any other systematic theology that even comes close to being as objectively true as does Acts 9 Dispensational Open Theism. There isn't any of it that stands as mere simple blind belief or personal opinion. Those who hold to it are not the sort that go for blind belief and personal opinion. They are the sort that are persuaded by reason and the PLAIN reading of scripture and even then, they aren't so convinced as to think they can't be shown where they've made an error. In fact, that was Bob Enyart's number one question for God. He repeatedly stated that if he could ask just one question and get a straight audible answer from God Himself, he would ask, "What teachings do I have wrong?". The pursuit of the objective truth is genuinely the hallmark of this doctrinal system as well as those who hold to it.
Clete
