My name is legion, for I am many!

I heard another great episode of Radio Lab, a radio show out of NYC whose podcast I subscribe to on Itunes. Anybody who has yet to discover the awesomeness of podcasts is missing out on a fantastic way to get news and enterainment, which is to say, a fantastic way to keep yourself occupied while you're running on a treadmill or doing the dishes.

Radio Lab is a science news show, with each week devoted to exploring a new science or technology issue. It regularly blows my mind. They often get into the ethical and philosophical issues raised by scientific discoveries.

This past episode featured an interview with Brian Greene, perhaps the world's most handsome and well-known astrophysicist. He's written several books on cosmology and astrophysics for laypeople, at least one of which was a bestseller. He also "starred" in a PBS special about string theory a while back. (I actually have an active side-interest in cosmology and astronomy, though I have no training in physics. Therefore I appreciate these attempts to expose laypeople like me to the mind-boggling weirdness of modern physics).

So, the show was about Greene's theory that there are many exact copies of our planet in the universe. Actually, to be more precise, there are infinite exact copies of our planet. And when I say exact, I mean exact. There are an infinite number of planets where an entity who looks exactly like me, down to the last quark, and who has had the exact same experiences as me, is typing this exact same sentence at this precise moment.

Huh?

His argument is actually fairly straightforward. If the universe is infinite, as Greene suspects, and if there are a finite number of ways that particles can combine, then, eventually, you're going to get a repeat. His analogy is this: give the clothes in your wardrobe, eventually you'll have to repeat an outfit. And if you lived for infinity, then you'd wear any given outfit infinity times (since any fraction of infinity is still infinity).

What's more, there are also infinite numbers of very slightly different me's. One hair out of place, or darker hair, or good at karate...etc.

Just some bizarre stuff, huh?

Nietzsche spoke of something he called "eternal return." He believed that the world would repeat itself, over and over and over again. It was kind of a crazy idea...turns out, he was perhaps onto something.

p.s.
This title comes from the gospels, when Jesus was casting out demons. Most recently, it comes from the movie Ghost Rider, which I watched so you don't have to. Don't see Ghost Rider.