The text of this post has been translated from Dutch to English with DeepL. It will be manually edited and streamlined soon.
THE IMAGE of the hexagram: a large, opened mouth. Upper teeth in upper jaw, lower teeth in lower jaw. In between, the open oral cavity, and maybe in the depths you can see the uvula and the dark shaft of the oesophagus? The extended meaning of jaws: feeding, eating.
Below is the Thunder, the ultimate moving. Above is the Mountain, the archetypal image of non-movement.
A jaw has two halves: one half moves, while the other stays in place. Since Victorian times, we have been expected to move our jaws according to specific etiquette. The upper jaw - and thus the entire skull, to which it is connected - acts as an immobile Mountain. Nor does the neck and the rest of the spine give way during the opening and closing of jaw and mouth. The body is Victorian straight and rigid. Unmoving. The lips give way only to let in a bite, but otherwise stay neatly together. In cultivated eating, the lower jaw stands alone, leaving little in the way of Burgundian ramp-pleasure.
A crocodile has nothing to do with named jaw etiquette. Its jaws, in their movement and emotion, are one with its trailing spine and mighty tail. Eating is a matter of the whole body, certainly not an isolated grinding lower jaw. The crocodile's lower jaw depicts the Mountain, his upper jaw and spine the Thunder. Try to imitate that movement pattern at today’s supper. Jaw and tail like a lightning bolt.
Etiquette equally prohibits all manner of eating noises, as you can see in the spaghetti scene from the Japanese film Tampopo.
A clam does not hà ve a mouth and jaw, it is entirely mouth and jaw. It lacks torso, arms and legs, but it does have soft lips, a palate, stomach and gut, and a poop hole. All soft and fragile. The hard calcareous shells are protective armour and jaw at the same time. A jaw that closes decisively and stays closed when approaching predators; one that opens to let tasty morsels float in. An ultimate land of milk and honey?
A double shell and the animal jaw are two different things. They have, to my knowledge, no direct evolutionary connection. Yet the form and function of the hinged clam shell and the jaws of fish, quadruped and bird have a handful of similarities.
If an oyster already has a jaw, who will say what the lower jaw and what the upper jaw are? The characteristics of Thunder and Mountain are now reflected in the opening or closing of the two shell halves.
And what is true for eating is equally true for flowing in the opposite direction: speech. Once closed, it takes a long time for the clam to know the coast is safe and open again.
Jaws and teeth manage the boundary between the outer world and the inner. You bite off a piece of a juicy apple with your teeth. A small, tasty piece of that outside world. You chew it, swallow it - and after a few hours, the notion of 'apple' disappears and it is transformed as your blood. An ultimate loving - the highest degree of identification - open the jaw, bite, chew, swallow and out-there becomes in-here.
But if that outside is dirty, if it stinks, spoiled and mouldy, keep your molars together. Don't let the filth come in. For deterrence, show your teeth. Your jaw like a medieval gate with portcullis, no entrance!!!
The furthest the jaws spread in a yawn, of all reflexes the least explored and understood. A yawn out of boredom is not an athlete's yawn prior to a competition. What does a gaping wound have in common with a drug store gaper? What we do know is that yawning is utmost contagious. And not just between conspecifics. Humans yawn, dogs and cats, our Amazon parrot yawns, hippos and turtles, and they all stimulate each other to yawn further. It is not known yet whether a yawning oyster makes conspecifics yawn.