April 2014

Help Wanted: Moving Naturalism Forward

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Update: This request received an amazing response! I had to make a tough choice, but I’ve picked someone to do the paid work of making a careful outline and suggesting possible excerpts. Thanks for everyone who sent a query.

Following ideas mentioned in the comments, however, there’s no reason why anyone cannot simply volunteer their own suggestions for parts of the videos that would make good excerpts. So, if anyone is so motivated, feel free to leave suggestions in the comments to this post. We might not be able to take all of them, but anything sensible will be considered. Thanks!

It’s been a year and a half since the Moving Naturalism Forward workshop, which featured a great line-up of thinkers: Jerry Coyne, Richard Dawkins, Terry Deacon, Simon DeDeo, Dan Dennett, Owen Flanagan, Rebecca Goldstein, Janna Levin, Massimo Pigliucci, David Poeppel, Alex Rosenberg, Don Ross, and Steven Weinberg. Fortunately we got the whole thing on video, so the conversations are preserved for posterity. Unfortunately, that amounts to ten videos, each about an hour and a half long. Not a quick watch for someone who just wants the highlights!

Moving Naturalism Forward: Day 1, Morning, 1st Session

So ever since the workshop, I’ve been wanting to go through the entire video record and make it more organized and digestible. That basically amounts to two things:

  1. Create a semi-detailed listing of who says what, when. So someone who wanted to hear Dan Dennett’s defense of free will could just skip right to that part of the relevant video — and could also see who mounted a challenge to it.
  2. Edit the long videos into much shorter highlights. Some very short bits of rhetorical brilliance, and/or some medium-length exchanges of separate interest.

I’ve been meaning to re-watch all the videos myself and do the above tasks, but it’s pretty clear that other obligations are in the way and it’s not going to happen. I have someone who will do the actual video editing, so really it’s about watching all the videos and making some intellectual/artistic decisions about what snippets might be good on their own.

So — anyone want to do it? This would be a paid gig, although it’s nothing you’d earn a living on, I promise you. I’m looking for a person with some kind of background both in science and philosophy, who can follow all the discussions and sensibly dissect them. Maybe about a week’s worth of work or a bit less, although it wouldn’t all have to be done within a week.

If you’re interested, shoot me an email (not a comment here), explaining a bit about what your background is. It’s not an enormous rush, although I’d like to get it done sooner rather than later. Could be fun!

Help Wanted: Moving Naturalism Forward Read More »

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A Leap in Energy

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The discovery by BICEP2 of the signature of gravitational waves in the cosmic microwave background — if it holds up! — is not only good evidence for inflation in the very early universe, it’s a fairly precise indication that inflation occurred at a very high energy scale. I thought of a vivid way to emphasize just how high that energy is.

Particle physicists like to keep things simple by characterizing all physical quantities in terms of a single kind of unit — typically energy, and typically measured in electron volts. That’s part of the magic of natural units. We live in a world governed by relativity, so the speed of light c provides a natural unit of velocity. We also live in a world governed by quantum mechanics, so Planck’s constant ℏ provides a natural unit of action. And we live in a world governed by statistical mechanics, so Boltzmann’s constant k provides a natural conversion between energy and temperature. We therefore set these quantities equal to unity, ℏ = c = k = 1. Once that’s done, mass and temperature have the same units as energy. Time and distance have units of 1/energy. Energy density is energy per unit spatial volume, which works out to (energy)4. This kind of reasoning makes particle physicists happy, since they like to think of everything in terms of energy scales.

So, thinking about everything in terms of energy scales, what’s the energy of everyday life? It makes sense to choose room temperature, about 295 Kelvin. That works out to about 0.02 electron volts, which we can call the temperature of everyday life:

E_{\rm everyday} = 2 \times 10^{-2}\, {\rm eV}.

One way of thinking about the progress of fundamental physics is to track the progress of our understanding to higher and higher energy scales. The highest energies we’ve ever probed in experiments here on Earth are those at the Large Hadron Collider. The last run of the LHC reached energies of 8 TeV, or 8×1012 eV. But it would be an exaggeration to say that we really understand those energies; when protons collide at the LHC, their energies are distributed among a number of particles in each event. That’s why the heaviest particles we’ve ever found are the Higgs boson and the top quark, both with masses a bit under 0.2 TeV. So let’s call that the highest energy we’ve understood through experiments here on Earth:

E_{\rm understanding} = 2 \times 10^{11}\, {\rm eV}.

Thus, the progress of science has extended our understanding a factor of 1013, thirteen orders of magnitude, above our everyday experience:

E_{\rm understanding}/E_{\rm everyday} = 10^{13}.

Not too shabby, for a species of jumped-up apes with only an intermittent dedication to the ideals of rationality and empiricism.

Now let’s turn to inflation. The great thing about detecting gravitational waves in the CMB is that, in contrast with the density perturbations we’ve known about for some time, the gravitational wave amplitude depends solely on the expansion rate during inflation, not on any details about the scalar-field potential. And the expansion rate is directly related to the energy density (energy to the fourth power) by general relativity itself. So measuring the amplitude, as BICEP2 did, tells us the inflationary energy scale directly. And the answer is:

E_{\rm inflation} = 2 \times 10^{25}\, {\rm eV}.

For comparison, the reduced Planck energy (where “reduced” means “including the factor of 8π where it should be”) is 2×1027 eV, a mere stone’s throw away.

So, you can do the math yourself. Inflation was going on at energy scales that exceed those we explore here on Earth by a factor of about

E_{\rm inflation}/E_{\rm understanding} = 10^{14}.

In other words, BICEP2 has extended our experimental reach, as measured by energy scale, by an amount (1014) slightly larger than the total previous progress of all of science (1013).

We don’t, of course, understand everything between LHC energies and inflationary energies, not even close. But we (the royal “we”) have been able to make an enormous extrapolation, using scientific reasoning, and get the right answer. It’s a big deal.

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I’m Not Sure That’s How Probability Works, Walter

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Tonight marks the debut of John Oliver’s Last Week Tonight on HBO. JenLuc Piquant reminds us of one of the former Daily Show correspondent’s finest moments: confronting Walter Wagner on why he thought black holes from the LHC were a threat to the existence of the Earth.

I’m Not Sure That’s How Probability Works, Walter Read More »

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Guest Post: Max Tegmark on Cosmic Inflation

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Max TegmarkMost readers will doubtless be familiar with Max Tegmark, the MIT cosmologist who successfully balances down-and-dirty data analysis of large-scale structure and the microwave background with more speculative big-picture ideas about quantum mechanics and the nature of reality. Max has a new book out — Our Mathematical Universe: My Quest for the Ultimate Nature of Reality — in which he takes the reader on a journey from atoms and the solar system to a many-layered multiverse.

In the wake of the recent results indicating gravitational waves in the cosmic microwave background, here Max delves into the idea of inflation — what it really does, and what some of the implications are.

Thanks to the relentless efforts of the BICEP2 team during balmy -100F half-year-long nights at the South Pole, inflation has for the first time become not only something economists worry about, but also a theory for our cosmic origins that’s really hard to dismiss. As Sean has reported here on this blog, the implications are huge. Of course we need independent confirmation of the BICEP2 results before uncorking the champagne, but in the mean time, we’re forced to take quite seriously that everything in our observable universe was once smaller than a billionth the size of a proton, containing less mass than an apple, and doubled its size at least 80 times, once every hundredth of a trillionth of a trillionth of a trillionth of a second, until it was more massive than our entire observable universe.

We still don’t know what, if anything, came before inflation, but this is nonetheless a huge step forward in understanding our cosmic origins. Without inflation, we had to explain why there were over a million trillion trillion trillion trillion kilograms of stuff in existence, carefully arranged to be almost perfectly uniform while flying apart at huge speeds that were fine-tuned to 24 decimal places. The traditional answer in the textbooks was that we had no clue why things started out this way, and should simply assume it. Inflation puts the “bang” into our Big Bang by providing a physical mechanism for creating all those kilograms and even explains why they were expanding in such a special way. The amount of mass needed to get inflation started is less than that in an apple, so even though inflation doesn’t explain the origin of everything, there’s a lot less stuff left to explain the origin of.

If we take inflation seriously, then we need to stop saying that inflation happened shortly after our Big Bang, because it happened before it, creating it. It is inappropriate to define our Hot Big Bang as the beginning of time, because we don’t know whether time actually had a beginning, and because the early stages of inflation were neither strikingly hot nor big nor much of a bang. As that tiny speck of inflating substance doubled its diameter 80 times, the velocities with which its parts were flying away from one another increased by the same factor 2^80. Its volume increased by that factor cubed, i.e., 2^240, and so did its mass, since its density remained approximately constant. The temperature of any particles left over from before inflation soon dropped to near zero, with the only remaining heat coming from same Hawking/Unruh quantum fluctuations that generated the gravitational waves.

Taken together, this in my opinion means that the early stages of inflation are better thought of not as a Hot Big Bang but as a Cold Little Swoosh, because at that time our universe was not that hot (getting a thousand times hotter once inflation ended), not that big (less massive than an apple and less than a billionth of the size of a proton) and not much of a bang (with expansion velocities a trillion trillion times slower than after inflation). In other words, a Hot Big Bang did not precede and cause inflation. Instead, a Cold Little Swoosh preceded and caused our Hot Big Bang.

Since the BICEP2 breakthrough is generating such huge interest in inflation, I’ve decided to post my entire book chapter on inflation here so that you can get an up-to-date and self-contained account of what it’s all about. Here are some of the questions answered:

  • What does the theory of inflation really predict?
  • What physics does it assume?
  • Doesn’t creation of the matter around us from almost nothing violate energy conservation?
  • How could an infinite space get created in a finite time?
  • How is this linked to the BICEP2 signal?
  • What remarkable prize did Alan Guth win in 2005?

Guest Post: Max Tegmark on Cosmic Inflation Read More »

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Twenty-First Century Science Writers

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I was very flattered to find myself on someone’s list of Top Ten 21st Century Science Non-Fiction Writers. (Unless they meant my evil twin. Grrr.)

However, as flattered as I am — and as much as I want to celebrate rather than stomp on someone’s enthusiasm for reading about science — the list is on the wrong track. One way of seeing this is that there are no women on the list at all. That would be one thing if it were a list of Top Ten 19th Century Physicists or something — back in the day, the barriers of sexism were (even) higher than they are now, and women were systematically excluded from endeavors such as science with a ruthless efficiency. And such barriers are still around. But in science writing, here in the 21st century, the ladies are totally taking over, and creating an all-dudes list of this form is pretty blatantly wrong.

I would love to propose a counter-list, but there’s something inherently subjective and unsatisfying about ranking people. So instead, I hereby offer this:

List of Ten or More Twenty-First Century Science Communicators of Various Forms Who Are Really Good, All of Whom Happen to be Women, Pulled Randomly From My Twitter Feed and Presented in No Particular Order.

I’m sure it wouldn’t take someone else very long to come up with a list of female science communicators that was equally long and equally distinguished. Heck, I’m sure I could if I put a bit of thought into it. Heartfelt apologies for the many great people I left out.

Twenty-First Century Science Writers Read More »

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Talks on God and Cosmology

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Hey, remember the debate I had with William Lane Craig, on God and Cosmology? (Full video here, my reflections here.) That was on a Friday night, and on Saturday morning the event continued with talks from four other speakers, along with responses by WLC and me. At long last these Saturday talks have appeared on YouTube, so here they are!

First up was Tim Maudlin, who usually focuses on philosophy of physics but took the opportunity to talk about the implications of God’s existence for morality. (Namely, he thinks there aren’t any.)

"Cosmology, Theology and Meaning" - Tim Maudlin

Then we had Robin Collins, who argued for a new spin on the fine-tuning argument, saying that the universe is constructed to allow for it to be discoverable.

"God and the Fine-Tuning of the Universe for Discovery" - Robin Collins

Back to Team Naturalism, Alex Rosenberg explains how the appearance of “design” in nature is well-explained by impersonal laws of physics.

"How Physics Fakes Design, and Makes Things Difficult for Theism" - Alex Rosenberg

Finally, James Sinclair offered thoughts on the origin of time and the universe.

"Cosmology and Cosmologists within the 'Does God Exist' Question" - James Sinclair

To wrap everything up, the five of us participated in a post-debate Q&A session.

Concluding Comments and Panel Q&A

Enough debating for me for a while! Oh no, wait: on May 7 I’ll be in New York, debating whether there is life after death. (Spoiler alert: no.)

Talks on God and Cosmology Read More »

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Chaos, Hallucinogens, Virtual Reality, and the Science of Self

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Chaotic Awesome is a webseries hosted by Chloe Dykstra and Michele Morrow, generally focused on all things geeky, such as gaming and technology. But the good influence of correspondent Christina Ochoa ensures that there is also a healthy dose of real science on the show. It was a perfect venue for Jennifer Ouellette — science writer extraordinaire, as well as beloved spouse of your humble blogger — to talk about her latest masterwork, Me, Myself, and Why: Searching for the Science of Self.

Jennifer’s book runs the gamut from the role of genes in forming personality to the nature of consciousness as an emergent phenomenon. But it also fits very naturally into a discussion of gaming, since our brains tend to identify very strongly with avatars that represent us in virtual spaces. (My favorite example is Jaron Lanier’s virtual lobster — the homuncular body map inside our brain is flexible enough to “grow new limbs” when an avatar takes a dramatically non-human form.) And just for fun for the sake of scientific research, Jennifer and her husband tried out some psychoactive substances that affect the self/other boundary in a profound way. I’m mostly a theorist, myself, but willing to collect data when it’s absolutely necessary.

Chaos, Hallucinogens, Virtual Reality, and the Science of Self Read More »

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Peregrinations

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Running around these days, doing some linear combination of actual work and talking about things. (Sometimes the talking leads to actual work, so it’s not a total loss.) If you happen to be in a sciencey kind of mood when I’m in your vicinity, feel free to come to a talk and say hi!

  • Today, if you happen to be in Walla Walla, Washington, I’ll be giving the Brattain lecture at Whitman College, on the Higgs boson and the hunt therefor.
  • Next week I’ll be in Austin, TX. On Thursday April 17, I’ll be speaking in the Distinguished Lecture Series, once again on the marvels of the Higgs.
  • In May I’ll be headed to the Big Apple twice. The first time will be on May 7 for an Intelligence Squared Debate. The subject will be “Is There Life After Death?” I’ll be saying no, and Steven Novella will be along there with me; our opponents will be Eben Alexander and Raymond Moody.
  • Then back home for a bit, and then back to NYC again, for the World Science Festival. I’ll be participating in a few events there between May 29 and 31, although precise spatio-temporal locations have yet to be completely determined. One will be about “Science and Story,” one will be a screening of Particle Fever, and one will be a book event.
  • I won’t even have a chance to return home from NYC before jetting to the UK for the Cheltenham Science Festival. Once again, participating in a few different events, all on June 3/4: something on Science and Hollywood, something on the Higgs, and something on the arrow of time. Check local listings!
  • A chance I will be in Oxford right after Cheltenham, but nothing’s settled yet.
  • That’s it. Looking forward to a glorious summer full of real productivity.

Peregrinations Read More »

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