Thursday, March 11, 2010

Nancy the Mad Hatter

Maybe Ramirez read our post yesterday titled Nancy in Wonderland.

Don't laugh, he could have:


Making Babies Cry

The E-Trade ads are better, but these are still pretty good:

Thanks to Hot Air.


Time and the Multiverse

Wired Magazine has an interview with physicist Sean Carroll in which he discusses his research on the nature of time. His work has led him to conclude that there are other universes, or more precisely, other regions of space that are closed off to our region - a version of the multiverse hypothesis. Carroll is not a theist but when he describes the origin of our space-time as a splitting off from a parent universe he seems to be describing God:

HT: Telic Thoughts Can you explain your theory of time in layman's terms?

Sean Carroll: [T]he particular aspect of time that I'm interested in is the arrow of time: the fact that the past is different from the future. We remember the past but we don't remember the future. There are irreversible processes. There are things that happen, like you turn an egg into an omelet, but you can't turn an omelet into an egg.

Basically, our observable universe begins around 13.7 billion years ago in a state of exquisite order, exquisitely low entropy [disorder]. It's like the universe is a wind-up toy that has been sort of puttering along for the last 13.7 billion years and will eventually wind down to nothing. But why was it ever wound up in the first place? Why was it in such a weird low-entropy unusual state?

That is what I'm trying to tackle. I'm trying to understand cosmology, why the Big Bang had the properties it did. And it's interesting to think that connects directly to our kitchens and how we can make eggs, how we can remember one direction of time, why causes precede effects, why we are born young and grow older. It's all because of entropy increasing. It's all because of conditions of the Big Bang. So the Big Bang starts it all. But you theorize that there's something before the Big Bang. Something that makes it happen. What's that?

Read the interview to see how Carroll answers the question. One of the things he says that I think he's mistaken about is this:

Even in empty space, time and space still exist. Physicists have no problem answering the question of "If a tree falls in the woods and no one's there to hear it, does it make a sound?" They say, "Yes! Of course it makes a sound!" Likewise, if time flows without entropy and there's no one there to experience it, is there still time? Yes. There's still time. It's still part of the fundamental laws of nature even in that part of the universe. It's just that events that happen in that empty universe don't have causality, don't have memory, don't have progress and don't have aging or metabolism or anything like that. It's just random fluctuations.

First, whether the tree makes a sound when there are no observers present depends on whether we define sound as a sensation or as compressions propagating through the air. The falling tree generates compression waves, to be sure, but the sensation of sound is produced by our hearing apparatus, not the tree. Sensations require senses, if there are no senses present there is no sensation, just energy.

Likewise with time in completely empty space. Time requires events, as Carroll acknowledges, but what events would there be in an empty space? If time exists despite the complete lack of events then what is it that's existing? It's not material, it's not energy, it's not a substance of any kind, so what could it be? If it's simply a dimension similar to the three dimensions of space we might wonder whether the idea of time apart from events makes any more sense than the idea of space apart from material objects makes sense.

The interview concludes with Carroll acknowledging that so far his view is merely speculative:

If you think you understand the rules of gravity and quantum mechanics really, really well, you can say, "According to the rules, universes pop into existence. Even if I can't observe them, that's a prediction of my theory, and I've tested that theory using other methods." We're not even there yet. We don't know how to have a good theory, and we don't know how to test it. But the project that one envisions is coming up with a good theory in quantum gravity, testing it here in our universe, and then taking the predictions seriously for things we don't observe elsewhere.

If this is all that his theory is, if there's no way to test it, then in what sense is it science? Why would it be okay to discuss Carroll's ideas in a science class but not the ideas of intelligent design theorists? Is it because Carroll's ideas are not a threat to metaphysical naturalism but the implications of ID are?