@stepkimb the analogy of the people in the water may hold true in other examples where perception dictates belief, but it doesn't hold to Terry's point. If the water is 60 degrees, then there is something to measure the truth against perception. In the instance of the bible, there is nothing to differentiate fact from perception or interpretation as is Terry's point.
Given the task of only being allowed to use the bible to study the bible, people come up with differing understandings. So religions use supplementals to curb those differences to their own interpretation. Otherwise, you'd be hard pressed to find a group who read ONLY the bible and came to the exact conclusions without any suggestions by an outside source.
Using your analogy, they all have different perceptions of what the water is. Lets say one of them thinks the water is too cold and goes around telling the others the water is 40 degrees. Then she tells them why she firmly believes it's that cold and gives people experience after experience why she can recognize it as being 40 degrees. Now others believe it's 40 degrees, despite their own perception.
Because of outside influences they perceive the water as being 40 degrees, even though the thermometer in the pool says 60.
This is the basics of Christianity. Except there has never been a thermometer available, only a person who tells everyone the water is too cold. The lack of a thermometer invalidates your argument and supports everyone else's who posted on this thread.