Rongxing Guo's abstract and text must be addressed separately. In the former, his assertions give a misleading impression of my paper (Force, 2008). I specifically listed Egypt and China as exceptions to an apparent spatial association of originating sites of ancient civilizations with the southern boundary of the Eurasian plate and associated active structures. Indeed, a main point of the paper is that primary civilizations in general, including Egypt and China, are far less closely associated with tectonic boundaries than the more numerous derivative ones, which include all those in Europe and several sprinkled through Asia.
Rongxing's main text, however, enlarges on his excellent point that all primary ancient civilizations of the eastern hemisphere are "hydraulic civilizations," that is, they are based on irrigation and transportation in the valleys of major rivers, and each reflects the seasonal cycle of flooding (cf. Butzer, 1976). Rongxing illustrates how intricately the development of such a civilization can be governed by fluvial processes. I concur (cf. Force, 2004), but would add that the nature of water supply varies greatly among the originating sites. Neolithic parental societies of some hydraulic civilizations took advantage of small tributaries (as at Choga Mami in the Zagros foothills; Oates & Oates, 1976) and of prolific springs (Maisels, 1999:108, 218), both along loci very near active tectonic boundaries (see also Jackson, 2006). Viewed this way, the early evolution of some primary civilizations is spatially tied to tectonic boundaries.
I think it is fruitless, however, to search for the most important environmental factors in the locations of civilizations' originating sites. An entire multidimensional matrix of factors must be involved. Ample water supply is clearly required, but is that more important to a nascent civilization than soils, or climate, or trade potential? Each of these has its adherents in the literature, and rightly so. Are all the environmental factors taken together determinative? In this context, I prefer to think of tectonism as a thread in an entire fabric of factors, much less obvious than some others, but apparently important based on the spatial distributions, especially for derivative civilizations, which are demonstrably non-random. Tectonism is a new factor that needs to be included in our thinking, one that is counterintuitive but rather apparent in retrospect. I look forward to presenting more of the factors involved