One never knows whether the Poet is speaking fact, fancy, or allegory. If fancy is clever enough, I doubt that the Poet would admit a difference betw… - Walter M. Miller

Centuries old, but recently widened, the highway was the same road used by pagan armies, pilgrims, peasants, donkey carts, nomads, wild horsemen out of the east, artillery, tanks, and ten-ton trucks. Its traffic gushed or trickled or dripped, according to the age and season. Once before, long ago, there had been six lanes and robot traffic. Then the traffic had stopped, the paving had cracked, and sparse grass grew in the cracks after an occasional rain. Dust had covered it. Desert dwellers had dug up its broken concrete for the building of hovels and barricades. Erosion made it a desert trail, crossing wilderness. But now there were six lanes and robot traffic, as before.

... for no change comes calmly over the world...

Insofar as thought could be governed at all, it could only be commanded to follow what reason affirmed anyhow; command it otherwise and it would not obey.