Jason JewellJohn, I think the only people who would seriously dispute this characterization are those who define Western civilization as an exclusively modern phenomenon or those who define it as an exclusively secular phenomenon. Often but not always these are the same people. These folks generally say that Western civilization begins in the Renaissance and develops through the Enlightenment. Theirs has always been a minority view.
My short answer to these people is that 1) Western civilization is not exclusively modern because the moderns in most cases are still self-consciously engaging and interacting with the pre-modern thinkers, institutions, etc., and 2) attempts to view the West as purely secular don’t have nearly as much power to explain numerous features of Western society. The “secularization” thesis that gained so much traction among scholars in the 20th century is now being abandoned.
I hope this helps.