How do we know what we know? From what source do we put trust in to verify it? No one person is an expert in all fields and no one person has the resources and time to verify the massive amount of claims and information... we
must rely on our axioms, biases, presuppositions, a posteriori and a priori knowledge, and assumptions. We must pivot off of a foundation. We must start somewhere to arrive anywhere. The Map I think that has the most reliability and explanatory reach and power is the Scientific Map because it is a universal map. As Sir Martin Rees stated Science is the ultimate Global culture. It can be applied on a universal scale and is not limited to one region.
The foundational filter. There is no blank slate. There is always a filter or a mental map we come with to any debate or knowledge and that usually determines where our conclusions end up. Unless we agree on the premises and the epistemological method on how we obtain reliable information and what knowledge is trustworthy the conclusions will vary. Reality or Truth is not relative but the filters and mental maps that it passes through are dependent on the particular brain. The food is the same how it is digested and excreted is different. Does naturalism inform your metaphysics or does your metaphysics inform naturalism.
What I find interesting is that each person is fashioned by a variety of events, genetics and geography, experiences... and those can dictate which sources of information we trust. I am no relativist... I believe there is reality and truth but I do notice that many claims especially metaphysical are determined by geography and experience. As Hume said reason is the slave of the passions. I don't see any escape from this human dilemma. That is why conflict seems inevitable in human history. The human brain is not made of generic soil and the seeds planted may be different as well. What knowledge is coming in and how is it processed?