November 2012

Election Day

Here’s an entertaining explanation of why winner-take-all voting procedures generally evolve into two-party systems, typically forcing most voters to support candidates they don’t always agree with.

Minority Rule: First Past the Post Voting

But vote anyway! (If you are a US citizen, or a citizen of another municipality which happens to be voting today.) You never know when you might cast the deciding ballot.

I have to go figure out the jillion (okay, eleven) ballot initiatives we have to deal with in the barely-functional direct democracy called California. One of them — Prop 37, which requires labels on certain genetically modified foods — poses an interesting dilemma. On the one hand, the science seems to indicate that genetic modification doesn’t introduce any special health risks. (At least not to individuals; there may be deleterious effects on the diversity of food sources, but that’s a different issue.) On the other hand, giving consumers more true information is generally a good idea. Is it a weird kind of reverse-paternalism to not give people correct information because they might take the wrong message from it?

p.s. At the end of our Moving Naturalism Forward workshop, Jerry Coyne offered “I think the best someone can do to move naturalism forward is to vote for Obama.”

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South Pole Telescope and CMB Constraints

The South Pole Telescope is a wonderful instrument, a ten-meter radio telescope that has been operating at the South Pole since 2007. Its primary target is the cosmic microwave background (CMB), but a lot of the science comes from observations of the Sunyaev-Zeldovich effect due clusters of galaxies — a distortion of the frequency of CMB photons as they travel through the hot gas of the cluster. We learn a lot about galaxy clusters this way, and as a bonus we have a great way of looking for small-scale structure in the CMB itself.

Now the collaboration has released new results on using SPT observations to constrain cosmological parameters.

A Measurement of the Cosmic Microwave Background Damping Tail from the 2500-square-degree SPT-SZ survey
K. T. Story, C. L. Reichardt, Z. Hou, R. Keisler, et al.

We present a measurement of the cosmic microwave background (CMB) temperature power spectrum using data from the recently completed South Pole Telescope Sunyaev-Zel’dovich (SPT-SZ) survey. This measurement is made from observations of 2540 deg^2 of sky with arcminute resolution at 150 GHz, and improves upon previous measurements using the SPT by tripling the sky area. We report CMB temperature anisotropy power over the multipole range 650<ell<3000. We fit the SPT bandpowers, combined with the results from the seven-year Wilkinson Microwave Anisotropy Probe (WMAP7) data release, with a six-parameter LCDM cosmological model and find that the two datasets are consistent and well fit by the model. Adding SPT measurements significantly improves LCDM parameter constraints, and in particular tightens the constraint on the angular sound horizon theta_s by a factor of 2.7…[abridged]

Here is the first plot anyone should look for in a paper like this: …

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The Absolute Limits of Scientistic Arrogance

I have redefined them! Those limits, that is. This is the view of Father Robert Barron, in response to — well, something I said, but it’s hard to pinpoint exactly what. But I know it was me and not some other Sean Carroll, because there’s a video in which my picture appears a couple of times.

I think his remarks were spurred by Natalie Wolchover’s article about my piece on why the universe doesn’t need God. (Here is a related article, not quite a transcript of the above video but close, in which he mentions Natalie’s piece but not mine.) He may have read the original piece, although it’s unclear because he doesn’t link to anything specific, nor does he reference particular arguments from the essay itself. He also refers to a book I’ve written, but none of my books actually fit the bill. And he talks a lot about my arrogance and hubris. (I’ve finally figured out the definition of “arrogance,” from repeated exposure: “you are arrogant because you think that your methods are appropriate, when it fact it’s my methods that are appropriate.”)

In any event, the substance of Fr. Barron’s counter-argument is some version of the argument from contingency. You assert that certain kinds of things require causes, and that the universe is among those things, and that the kind of cause the universe requires is special (not itself requiring a cause), and that special cause is God. It fails at the first step, because causes and effects aren’t really fundamental. It’s the laws of nature that are fundamental, according to the best understanding we currently have, and those laws don’t take the form of causes leading to effects; they take the form of differential equations, or more generally to patterns relating parts of the universe. So the question really is, “Can we imagine laws/patterns which describe a universe without God?” And the answer is “sure,” and we get on with our lives.

As good scientists, of course, we are open to the possibility that a better understanding in the future might lead to a different notion of what is really fundamental. (It is indeed a peculiar form of arrogance we exhibit.) What we’re not open to is the possibility that you can sit in your study and arrive at deep truths about the nature of reality just by thinking hard about it. We have to write down all the possible ways we can think the world might be, and distinguish between them by actually going outside and looking at it. This is admittedly hard work, and it also frequently leads us to places we weren’t expecting to go and perhaps even don’t much care for. But we’re a flexible species, and generally we adapt to the new realities.

Which reminds me that I still owe you a couple of reports from the naturalism workshop. Coming soon!

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