Indians, Religion, Nada Brahma.

The native peoples of the Americas and those of the subcontinent of India are called Indians.    Using this now is a linguistic convention, it conveys no meaning — except reminding us of an accident of history.  Had Vasco da Gama completed his voyage before Columbus, Columbus would not have thought that he reached India.   Certainly no study of geography, of anthropology, or of virtually any subject would group India and the Americas together alone.

The analogy is this: either the word "religion" is a linguistic convention, like "Indian" and thus includes Christianity and the "religion of the ancient Greeks" together; or else "religion" is a coherent entity,  and then Christianity is a religion and the ancient Greeks had no religion, just like the Indians of the new world never set foot in India.

If we insist that the linguistic convention "religion" actually reflects something real in the world and not just some arbitrary set like {locomotives, politicians}, we run into all kinds of problems.

A trivial one is that music itself is "religion".   The secular state which must not promote any religion is thus forbidden from promoting music. 

In general, one by one, as you examine it, every human action turns into a religious action.