Much of this know-how was even widely applied during the lifetimes of some now living. Our simple loss of such important knowledge flies in the face of deep assumptions in the water we all grew up in: progressivism, that knowledge is always increasing, that at least the best First World cultures since the Renaissance have always moved forward.

The good news is that some version of this knowledge keeps getting rediscovered.

The bad news is that the knowledge seems to be mostly tacit and (so far) unteachable.