May | 2016 | Ramin Skibba

Here are excerpts from a new book review and movie review I’ve written recently for Inside Science News Service. I have a few additional thoughts about Sean Carroll’s book, below this excerpt.

Sean Carroll’s ‘Big Picture’ Tours Physics And Philosophy

In a new book, Sean Carroll brings together physics and philosophy while advocating for “poetic naturalism.”

Quantum physics, cosmology, existentialist philosophy and morality may seem like disparate subjects. But Sean Carroll, a theoretical physicist at Caltech, ties them all together into a cohesive and comprehensive worldview he calls “poetic naturalism.” He lays out his views while trying to find meaning in a vast and chaotic universe in his newly published book, “The Big Picture” (Dutton, Penguin Random House Inc.).

Having written two previous popular physics books as well as being active on Twitter and his blog, Carroll takes an interest in communicating complex scientific discoveries. In his new book, he describes some of the fundamental ideas in modern physics with a philosophical lens, while exploring life’s biggest mysteries: the origin of the universe and the meaning of life itself. At the same time, with references to Wile E. Coyote, Captain Kirk and “Bill and Ted’s Excellent Adventure,” he avoids an overly serious tone.

In recent years, prominent scientists like Neil deGrasse Tyson, Bill Nye and Stephen Hawking have downplayed the importance of philosophy or even denigrated it. Carroll is not among this crowd.

“There are a lot of scientists and science promoters who have said not entirely complimentary things about philosophy, but that misses the point about what it’s for,” Carroll said in an interview. “The purpose of philosophy is not to be the handmaiden of science.”

(Credit: Dutton, Penguin Random House, Inc.)

Though his Ph.D. is in physics, Carroll has a strong interest in philosophy as well, and minored in it in college. He sees philosophy as a method for interpreting science and for a deeper understanding of physical phenomena. He uses philosophical concepts such as causality, determinism and mind-body dualism to explore everything from the tiniest subatomic particles to the accelerating expansion of the universe — as well as the role humans play somewhere in between.

For Carroll, naturalism means that there’s one world, the natural world, it obeys the laws of nature, and you can discover it using science. To this he adds that “there are many ways of talking about the world,” stories that people can tell to make sense and meaning of the world and their place in it. He even address issues of free will, consciousness, ethics, and life after death…

…The situation becomes murkier when Carroll discusses quantum mechanics, the interpretation of which has continually generated debates among physicists and philosophers since Max Planck and Albert Einstein discovered light “quanta” in the early 20th century. Physicists interpret quantum systems with probabilities: for example, for a hydrogen atom, the electron doesn’t have a particular position or momentum, but if someone measures them, it has probabilities of being observed in particular states.

Carroll supports the controversial “many-worlds interpretation” in which every quantum possibility is literally a separate world (or universe). We happen to live in one of them, and we have no way of seeing or even confirming the existence of the many unobservable parallel universes. This interpretation seems to conflict with his claim of endorsing a “sparse ontology,” which would mean accepting only a few fundamental concepts for describing the natural world.

“What I took Carroll to be promoting was a kind of ‘verificationism’: what is true is what can be measured,” said Elise Crull, philosopher of science at the City College of New York. “But what counts as ‘measurable,’ and how we distinguish theoretical from observational statements, are complex issues.” This is why, she argues, philosophers considered the view problematic and abandoned it long ago…

[For more, check out the entire story in Inside Science, published on 19 May 2016. Thanks to Chris Gorski and Emily DeMarco for editing assistance.]

Additional thoughts:
I think Carroll’s book does a great job of tying together so many disparate concepts, and I commend his efforts to communicate philosophical ideas. It’s important to encourage people to think and talk about “what it all means.” However, I think Carroll comes across as a little overconfident sometimes, as if he has all the answers. (But he’s more modest at other times.) Furthermore, he’s clearly more of an expert on the physics than the philosophy. His philosophical views don’t seem very nuanced or even self-consistent, and his book lacked a discussion of some important questions. (Exactly what are “laws” of nature and what do they tell us about how things actually behave? How do we assess the simplicity or predictive or explanatory power of a scientific theory?) He also missed some influential philosophers and physicists who have studied “scientific realism” in the context of cosmology and quantum physics for decades.

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Here’s a few new stories I reported on and wrote for Inside Science News Service over the past couple weeks:

Physicists Look Beyond WIMPs For Dark Matter

Physicists are on the hunt for elusive dark matter, the hypothesized but as yet unidentified stuff that makes up a large majority of the matter in the universe. They had long favored “weakly interacting massive particles,” known as WIMPs, as the most likely dark matter candidate, but after an exhaustive search, some scientists are moving on to more exotic particles.

Most estimates suggest that there’s 5-6 times as much dark matter as there are things that we can see, such as galaxies, stars, and planets. Yet physicists know very little about what the mysterious dark matter particles actually are, as they cannot be directly observed and barely interact with normal matter.

New research leaves dwindling room for WIMPs, motivating a search for other particles that could fit the bill.

“The WIMPs are getting harsh experimental scrutiny, and may get ruled out,” said Kathryn Zurek, a physicist at Lawrence Berkeley National Laboratory in California. [Note: She later clarified that WIMPs may become more “strongly constrained” rather than “ruled out.”]

Physicists have used the Large Hadron Collider’s ATLAS experiment to probe for potential dark matter particles. (Credit: CERN)

Zurek and others presented ongoing work on dark matter alternatives to WIMPs in April at an American Physical Society meeting in Salt Lake City. “We should broaden the searchlight, and the natural place is to go lighter,” Zurek said.

She and her colleagues are looking into less massive particles that interact more weakly with ordinary matter. These include an array of particles with exotic names like “axion,” “sterile neutrino,” and “Higgsino,” a theoretical super-partner of the famous Higgs boson.

Axions are hypothetically abundant particles originally proposed in the 1970s to solve a problem with nuclear physics. In the presence of a powerful magnetic field, these minuscule particles, which are lighter than electrons, are predicted to turn into detectable photons. In spite of years of searching, however, they have yet to be found. But the Axion Dark Matter eXperiment, currently being upgraded, should definitely determine whether the particle exists, said Leslie Rosenberg of the University of Washington in Seattle.

Kevork Abazajian, a cosmologist at the University of California, Irvine, sees a new trend in the field over the past decade. “The new generation of early-career physicists is more open to dark matter other than WIMPs,” he said.

He argued that physicists should consider sterile neutrinos, which interact even more weakly than their neutrino counterparts. As they decay, the particles—which are tinier than electrons—could produce detectable X-ray radiation such as that observed in clusters of galaxies. But scientists struggle to distinguish between X-rays that could be emitted by sterile neutrinos versus traditional astrophysical events. Research along these lines suffered a setback when Japan’s powerful X-ray satellite Hitomi broke into pieces last month. But it may have accumulated limited science data before it was lost…

[For more, check out the entire story in Inside Science, published on 28 April 2016. Thanks to Chris Gorski and Sara Rennekamp for editing assistance.]

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