Editors' Note: This article is part of a Public Square conversation on Technology and Spirituality. Read other perspectives here.

Quick—what is my body language telling you? Trick question—you can't see me, because the only medium connecting us is words on a screen. You can't read my body language or make eye contact with me. I'm a disembodied voice. So are many of the other people you'll "interact" with today—friends on Facebook, email contacts, bloggers. To an extent never before seen, we're living in an age of disembodied communication, ushered in by the Internet. This has profound ramifications for religion, because religion has always depended on ritual, things we do with our bodies.

Episcopal parishioners kneel for Communion. Muslims bow in salat toward Mecca. These bodily actions aren't mere sideshows to religions about Christ or Allah. These behaviors are these religions, just as a dance is the steps that make it up. Religion, then, is something people do, not just something they believe or think. This under-recognized truth points to a key distinction in semiotics, or the study of signs, one which sheds surprising light on the difficult relationship between Internet culture and religion.

Namely, embodied religion raises philosopher Charles S. Peirce's distinction between symbols, which are arbitrary, and semiotic indexes, which aren't.

Words are arbitrary symbols. The word "fire" doesn't have an intrinsic connection to high-speed oxidation; it's just a social convention. But red-orange flames, intense heat, and crumbling ashes are indexes of fire; they are causally, intrinsically connected to it. In fact, they are fire.

So the word "fire" communicates the message "Fire!" by connecting an arbitrary sound with a real-world event.

But flickering flames communicate the message "Fire!" by being fire.

Unlike words or symbols, indexes are inseparably connected to the things they point to. This makes them much harder to fake. The anthropologist Roy Rappaport pointed out that ritual, perhaps counterintuitively, depends on such hard-to-fake indexes. Take animal rituals. If a subordinate dog play-fighting with another dog rolls over and exposes its belly, this is an index that the fight is play and not earnest. Exposing the soft belly isn't symbolic of trust and vulnerability. It is trust and vulnerability. The action is the same thing as the message.

The same thing is true for seemingly pointless human rituals. Spending two months' salary on an engagement ring is, literally, an investment in the relationship. Sure, the suitor could simply say "I'm invested in you, baby," but words are free. Words can express a commitment. But they're not tangible signs of a commitment. An expensive engagement ring, then, is a way of putting "skin in the game."

(Remember the disturbing movie Kids, where the womanizer Telly seduces girls by lying about loving them. Lying is much, much easier with words than with indexes, because indexes require action.)

On the religious front, showing up for church each Sunday is an investment in the congregation. People who aren't really invested sleep in; thus, regular attendance is an honest index of commitment. Likewise, shaving your head to join a Buddhist monastery is commitment to the sangha. If you weren't actually committed, there's no way you'd drop out of society, don orange robes, and take a vow of celibacy. The shaved head, then, is Buddhist monkhood, not a symbol of it.