I do not hear many people talking about it, but there is a fundamental problem with talking about religions as "Western," "Eastern," or "Non-Western."

First, where is the dividing line between West and East? One option would be to use the border between Europe and Asia, along the path of the Ural Mountains. Another option would be to draw a longitude line cutting through Jerusalem. Strangely, few writers seem to address where they divide between West and East.

Second, how do you pick a location for a world religion with followers that migrate? For Hinduism, it makes sense to consider India the religion's center. For Christianity, there are reasons to pick Jerusalem and Rome. Though it would be reasonable to associate Protestantism with Germany and Orthodox with Constantinople/Istanbul in addition to that.

Then there's the inconsistent use of terminology to consider. The convention is to write about Christianity as a Western religion.

Some writers categorize Islam as Western, perhaps by analogy to Judaism. Others categorize Islam as Eastern, perhaps taking Jerusalem as a dividing line, although a look at a map shows Mecca is relatively close to Jerusalem. Still others, perplexingly, do not categorize Islam as either Western or Eastern.

Also, what do you do with something like the Aboriginal religions of Australia? Geographically, it would make sense to call them Eastern. In terms of the history of religion, it is not helpful to call them Eastern because they have little in common with the religions of East Asia. On the other hand, you might carve out a separate group from "Indigenous" and place Aboriginal religion there, along with Native American, Ainu, and others.