Earlier this week I complained on Twitter about having to read Huntington's "Clash of Civilizations" for the umpteenth time when virtually every serious IR scholar knows he's wrong. I really despise the "wrong but influential" line of argument, because it so often means that someone has been given influence in the literature for being both inflammatory and wrong, which is different than being wrong but influential on policy.
The gist of Huntington's argument is that in the post-Cold War period civilization will increasingly become a salient referent for conflict. While I do not have time to pick apart this argument in full, it does rest largely on civilization as a cultural constant, as most of the civilizations he recognizes reach back at least 1,000 years. To see how this assumption can be misleading, see the map of world religions in 1895 below.
Huntington is known for being politically incorrect, but thankfully he did not use "heathen" as a category (yellow). This simple example is not definitive, but illustrates that the way in which civilizations are conceived has changed in century between the creation of this map and the appearance of Huntington's article.