How much of the firm erets is covered by water?
Clearly, the folks who first put scripture into written form could not have answered that question (unless of course they were given the answer by divine inspiration, in which case they curiously chose not to make a record of it).
Should we nonetheless take their scripture into consideration, using it as some sort of guide or "filter for truth," when we answer that question today? If so, how does that help us, exactly?
You have dry erets and you have erets covered by water, but it is all erets.
Perhaps you can cite some specific verses in scripture to confirm that this was the perspective held by the original writers. But I wonder if there may be other verses that would tend to confuse the issue -- e.g. there might be something to support a notion like "go far enough out to sea and it's just water all the way down." I don't doubt that if someone in the Middle Ages had wanted to expound such a view, they would be able to find scriptural "evidence" to support it.
It's virtually impossible for a group to sustain a coherent description for some aspect of reality that they really don't comprehend, no matter how cohesive they may be in their shared world view. This is especially true (and obvious) when the group is unwilling to acknowledge what they don't understand.
autotelic adj. (of an entity or event) having within itself the purpose of its existence or happening.