To science, not even the bark of a tree or a drop of pond water is dull or a handful of dirt banal. They all arouse awe and wonder. - Jane Jacobs

Redundancy is expensive but indispensable.

Advanced cultures are usually sophisticated enough, or have been sophisticated enough at some point in their pasts, to realize that foxes shouldn't be relied on to guard henhouses.

The salient mystery of Dark Ages sets the stage for mass amnesia. People living in vigorous cultures typically treasure those cultures and resist any threat to them. How and why can a people so totally discard a formerly vital culture that it becomes vitally lost?