Someone commented on a blog post, “If atheism is a religion then not collecting stamps is a hobby.”

To this another commenter replied,

That only applies if you don’t go to stamp collecting sites and explain why stamp collecting is stupid, produce podcasts about why stamp collecting is stupid, write books on why stamp collecting is stupid, sue because someone want to promote stamp collecting, or hold rallies to celebrate non-stamp collecting.

Is atheism a religion?

Not in the sense that it is a belief in a god or Gods.   In this sense, Penn’s quip is absolutely true.

But’s this is not all that is contained in the term religion.

We might also say that a religious claim is one which rests upon unprovable truth claims.

Religion generally arise out of the search for meaning and truth.  An agnostic avoids making a religious claim when she says that she doesn’t know if there is or is not a god.

The atheist, on the other hand, makes a fundamental and unprovable truth claim that there is no God. This, in the sense that it is a belief about truth and meaning around which one orients one’s life, is a religious claim.

So you can see, the original commenter is insisting on a narrow definition of the term “religion” so as to avoid the fact that his belief is not ultimately based on reason.

Atheism is a religion like not believing in stamps is a hobby.