Plant your feet firmly on the earth. Affirm that you are fixed on the fundament. Reach your arms high, towards the sky. In one direction is the firmament, and in the other?
The earth, of course.
Let’s approach this another way. You know Atlas: he’s that bloke with the globe on his shoulders, right? So what’s he holding up?
The firmament. And where’s he standing?
On the earth. The Atlas mountains, now in Morocco, to be precise. (What would he be standing on if he were holding the earth – a turtle? Which is on another turtle, and so on all the way down?)
Never mind that firmament appears to have two feet firmly planted in it, m and m. It means the heavens. That globe Atlas is holding is the celestial sphere, not our planet, and really, in mythology, he’s holding the sky above the earth. And the sky, wherein the sun, moon, planets, and stars are fixed, is the firmament.
That seems a touch weird, doesn’t it? Although firm is not a hard word (no knocking stops in it), it has that sturdy hum like a diesel engine. And ment makes a noun of something – it pours concrete on a concept. But the heavens are mostly empty space with balls of hot gas spinning about in it. They’re the counterpoise to terra firma. So what silly person decided the heavens were the firmament?
I certainly found it confusing for a long time. When you get a sentence like the first verse of Psalm 19 (KJV), “The heavens declare the glory of God; and the firmament showeth his handiwork,” you can think firmament means the earth. But when you run up against Hamlet saying “This goodly frame, the earth, seems to me a sterile promontory; this most excellent canopy, the air, look you, this brave o’erhanging firmament, this majestical roof fretted with golden fire, why, it appears no other thing to me than a foul and pestilent congregation of vapours,” well, you’re going to get confused.
You wouldn’t be the first. Evidence suggests that the people who translated the Bible from Hebrew to Greek were also confused. Referring to the vault of the sky, the Hebrew word most likely meant “expanse” or “spread”, but in Syriac the same verb meant “condense” or “make solid” (probably the divergent senses both trace back to a sense meaning “tread” or “beat out metal”), and that led the Greek translators to make it “firm, solid structure” – which went from the Greek to the Latin, where it was rendered firmamentum, from a verb firmare meaning “strengthen”.
So much for a firm basis for interpretation! An error stands on another error standing on another… Turtles all the way down? No, the bottom turtle is standing on air, but no one’s noticed. And now it has the solidity of tradition! Good heavens.