Diplomacy among the aliens

One of the structural difficulties with any systematic study of civilizations is that the sample size of the category is rather small, as is clear in the few attempts to examine their progression (see Arnold Toynbee). Additionally, there's always the problem with how one generates a typology for something as fluid as civilization. Where does antiquity end, and the medieval period begin? One can get a rough sense of the discontinuities impressionistically. Consider the appearance of the Column of Phocas, erected in 608 AD. It may be correct that chronologically the Byzantine state and society on the eve of the expansion of Islam in the early 7th century was closer to the era of Charlemagne than Constantine, but many would argue that it was basically a Late Antique society more than an Early Medieval one. Certainly the Byzantines of that age would have agreed with that assessment (though one has ...