I picked this little book up as a remainder and he has an interesting chapter on the decline of the Roman Empire. He poses two general reasons for the fall and I quote:

"What we have come to realize since around 1970 is that the Roman Empire suffered from a shrinking of its population by 25 percent between 250 and 450 A.D. This demographic debacle, in turn, meant a diminishing production and tax base, as well as a shortage of soldiers to protect the far-flung imperial frontiers.

The cause of the population decline was the spread of epidemics since the middle of the third century: smallpox, bubonic plague, and some variety of venereal disease. The Roman Empire was lucky in avoiding pandemics in its first 250 years. It was generally healthy without any effective medicine. But when the disease germs came up the Nile valley from East Africa, following the route of human migration a hundred thousand years earlier, the population was extremely vulnerable, and its numbers severely eroded by disease.

There is a subsidiary cause for Roman decline: its operations as a slave society. Slaves do not reproduce their own numbers, and once big boosts of new slave population ceased with the ending of imperial conquests in the first century A.D., the size of the working population slowly but steadily declined.

The German economic historian Franz Oertel in the 1950s points to another drastic consequence of a slave economy. A slave economy initially allowed an increase of productivity through augmenting the slave-labor supply, but eventually inhibited an industrial revolution, which would have increased productivity through the invention and use of new machinery. Roman products remained at a simple level and could be reproduced by handicraft. By the fourth century, for example, the robust pottery industry of Greece was in sharp decline because other parts of the empire also learned to make pottery.

The decline in international trade in the Mediterranean in the fourth century was partly due to increasing piracy, but it was also due to lack of industrial innovation and of need for exchange of manufactured goods.

There was some kind of cultural cause for the decline of the ancient world. It was neither corruption of public spirit nor Christianity. It was due to the rise of the logocentric culture rooted in written text. This engendered, in general, a conservative, backward-looking frame of mind, hostile to critical military and technological innovation. It widened the gap between the highly literate elite and the still-illiterate masses. It aroused social strains that the imperial government would not, or perhaps could not, confront. Once the Visigoths had won a lucky battle or two, a general pessimism, docility and privatism settled in.

The ancients had a phrase for this. They said the world was "growing old." It was a mature culture. The Romans in late antiquity needed social and intellectual restoration, not more intensive cultivation of the classical heritage."
Whew! Anway, what do you all think of that???