But if you want me to interpret the Scripture you appear so interested in, here's my shot---
"Firmament" refers to something tangible. "Waters" refers to spirit, as it often does in the Bible. Heaven is therefore a real place encased by spirit, perhaps God Himself.
Zed,
I would disagree. It is true that water is a powerful image in biblical literature--as in all literature. It can be the source of life, death, cleansing depending upon the context of its use.
Here in the creation myths, the waters of the firmament are meant to symbolize or represent chaos.
Almost all creations myths move from scenes of disorder to order. This is done in some myths through battle--Marduk and Taimat in the Enuma Elish. Or through a sexual act-Eurynome and Ophion in some ancient Greek texts. In all some divine force orders chaos.
In Hebrew scripture, Yahweh does this purposefully and through language. There is no struggle and the universe as it emerges from chaos responds immediately to His command. God moving on the face of the waters is the divine force moving upon the primordial chaos. The firmament which he creates in the midst of the waters is the intrusion of His order upon this chaos.
The rest of the first creation story is about order created and constructed along a series of dualities or binary structures--light/darkness, land/water, vegetative life/animal life and final human life--male and female.
This notion of water as chaos gets revisited again later in Genesis with Noah. God calling about the waters of the firmament is in a sense God engaging in a "do over" going back a few steps. Notice after Noah survives the flood, God repeats the commandments earlier in Genesis.
And God blessed Noah and his sons, and said unto them, Be fruitful, and multiply, and replenish the earth. And the fear of you and the dread of you shall be upon every beast of the . . .
Notice, of course, that humankind repeats their mistake again with the Tower of Babel--human beings trying to become like God--in an attempt to reach heaven. It is humanities second fall through pride.
By the way most apocalyptic myths move the opposite--order to disorder.
Human level--great wars, embracing of evil practices.
Earthly level--earthquakes, famines, floods, etc.
Cosmic level--the stars fall from the sky, moon is uprooted etc.
Interesting and fascinating stuff.
By the way, enjoy the cat and mouse game with BB. The theme of the movie "War Games" applies to debates with him.
Cheers