In John's Gospel, Pilate asks Jesus the great philosophical question, "What is truth?". He didn't get an answer and we're still trying to figure it out.
Personally, I find the scientific framework, which can disprove a hypothesis but never absolutely prove something, rather compelling. It causes us to hold what we know to be true carefully, provisionally and with humility. It doesn't mean that we're never able to proclaim what we think we know. It also doesn't mean that everyone's understanding is as good as anyone else's. There are some things that we can know with greater certainty and others that we have to admit are our best guess based on the existing evidence.
It seems to me that this isn't a bad way to approach spirituality. Some religious views use the concept of absolute truth as a way of maintaining power, as something secure to hold on to. I can't help but think that this is a form of idolatry. Surely the only thing that's absolute, in a theological sense, is God? Our understanding of God and, even more, the ways in which we try to articulate that understanding are always incomplete, imperfect. At best, they act as a pointer to what we believe to be sacred.
This is ultimately true of even our most revered sources of revelation - the Bible, our Doctrines, the Salvation Army Songbook. All are human attempts to try and grasp the meaning of God and what a life dedicated to God should look like. They represent people's best understanding, in their own times and cultural contexts, of the truth available to them. They are written by people who were inspired by the Spirit of God and have been proven to have lasting impact because that same Spirit continues to inspire people through their words today.Yet they are not, in the fullest sense, Truth. They point to the Truth, in that they are trying to reveal God, but they don't replace Truth in an absolute sense.
As much as we might like certainty, and the sense of security that comes with it, we can end up creating idols when we overestimate our hold on the truth. At the same time, we close ourselves off to new revelation, new understandings, which might in fact open us up to greater knowledge and bring us closer to God.
As I write this, I'm keenly aware of two things. Firstly, I've come to these views based on the experience of being wrong thousands of times. Secondly, I could be completely wrong in what I'm saying now. But I'm ok with that. (And presumably you are too, or you should really be reading something else...)