What is a religion?

In a multi-part leadup to my opinion on the recent French law that enacted some serious prohibitions with regards to religious apparel in public schools, I want to start off by asking the simple question: What is a religion?

We all know the general aspects of a religion. A central text of some sort is a good start. It allows for codification of the rules that set the religion apart from others. Furthermore, it provides a mechanism of ensuring continuity, allowing future generations to follow the rules as laid down in the central text. Of course, you need those future generations so that your religion can grow to an appreciable size. Conversions are easy but strictly short-term.

Another common aspect of a religion is some sort of central figure. Examples of course are Jesus, Buddha, Mohammed. Other possible examples would be David Koresh, Jim Jones, Kim Jong-Il and others.

Wait, is that disagreement I hear? Is Jim Jones not on the same level as Jesus or Mohammed? Why is that? Well, Jim Jones at least kinda screwed up the central tenet of a religion ("be fruitful and multiply"). Be fruitful and commit suicide tends to preclude those future generations I was talking about that are so important for the success of a religion.

So, when is a cult not a religion? When is a religion simply a cult? The answer usually given is something along the lines of "We know what a religion is when we see it". Number of adherents is generally used as the dividing line in the sand. Looking at the populations of various religions is interesting, but not very illuminating. The Garbar branch of Zoroastrianism is listed as a "real" religion, with only 20,000 people. Offhand, I think that Kim Jong-Il has many more followers than that, but he doesn't get listed.

So, when does a religion become legitimate? Lets take Christianity as an example. Obviously, in the year 4 A.D or so, it was still a cult. How many people did it take for Christianity to become a real religion, how long?

The question is important. Religions almost by definition force their followers to do silly things to set themselves apart from the crowd. Often, rules that most people must obey are broken by those who claim that they are following the commandments of their religious text of choice. Using religion as an excuse, people carry weapons into schools, flout uniforms with impunity, subject their children to brainwashing and get excused from difficult examinations.

Can we draw a line? If someone shows up and makes a random demand and claims that it is religious, can we deny it to him while allowing religious freedom to others?

(part 2 will follow when I feel like it)

Oh, and a little food for thought