Caves are typically very stable geologic structures. That stability makes cave tourism possible, so, for example, tens of thousands of visitors have walked through Mammoth Cave in Kentucky not in trepidation, but in wonder. The giant hole in the limestone has even housed religious services, weddings, and, for a brief time, a small village of people suffering from tuberculosis, the last group led there by erroneous and quack medical advice (some got sicker in the cool damp air). The point: A cave like Mammoth Cave doesn’t change much over the course of a century; one can stand inside with little worry about a roof collapse.
Regardless of the stability of any system like a cave, there will be times when instability occurs. Equilibrium is a temporary condition. So, about 2,300 years ago, a Native American was in Mammoth Cave when a small, but personally devastating change took place, a little bit of disequilibrium that pinned him beneath a six-ton boulder that fell from the cave wall. Wrong place, wrong time. Possibly, he contributed to his demise by digging for gypsum or epsomite beneath the rock. More recently, during an Easter holiday, when Mammoth was closed for a day, cold air moved over Kentucky, entered the cave, and contributed to the collapse of the ceiling in the middle of the large room called the Rotunda. The rock fell where Park Rangers had often gathered tourists for an opening lecture on their cave tour.
Equilibrium and stability of place is comforting, but neither is permanent, even in the status of solid rock. Well, back to Plato if only for a moment. Plato has prisoners chained from birth to the inside of a cave, with each facing the interior wall. Behind them, and outside the cave, is a fire, and between the fire and the prisoners people walk, casting shadows on the wall of the cave. The shadows, in Plato’s allegory, are the “reality” that the prisoners know. In my take on the allegory, all of us walk around in a Cave of Culture. From our earliest times, we expect the kind of stability the cave appears to offer. Equilibrium is the status. Then, just as in Mammoth Cave, in our Cave of Culture something precipitates an unexpected roof collapse. For some generations, the collapse will be a minor nuisance with no major injuries: The status quo lies solidly in relative equilibrium.
But equilibrium is, as I said above, a temporary condition. Something like a cold front, a force from outside the cave, can cause disequilibrium and change the culture. And sometimes something from within, such as digging for gypsum, can cause disequilibrium and change the culture.
Look up. How stable is your cave’s roof?