Category: physics

Sabine Hossenfelder attempts to find real free will in the laws of physics

July 11, 2018 • 10:15 am

The two main positions about free will by those who already accept physical determinism are these:

a. They are incompatible: determinism completely effaces the possibility of free will;
b. They are compatible: although determinism may be true, and our actions controlled by the laws of physics, we can construe a definition of free will that is compatibile with this (“compatibilism”).

I’ve discussed the varieties of compatibilism before (which themselves are incompatible with each other), and don’t intend to do so here. Rather, I am trying to understand a new hypothesis that is said to give us some room for “true” free will.

Most philosophers who are determinists agree with b., but, as I’ve repeatedly made clear, I think the definition of “free will” as a species of action compatible with us being puppets to physical laws is just a semantic trick. The fact is that most people are dualists, conceiving of free will as a form of agency that allows us to choose any of several paths at a given point, and this is a rejection of determinism. (Those people fit in neither a nor b; they accept that determinism precludes free will only if determinism is all there is.)

To redefine “free will” as something other than how most people construe it is akin to redefining God as “love” or “the universe”: a similar semantic trick used by Sophisticated Theologians™ to allow people to accept that there’s a God in the absence of evidence for a deity. (Most believers, however, accept a theistic God—one who is personal and interacts with the Universe.) Both compatibilism and Sophisticated Theology™ have as part of their brief an attempt to reassure the less sophisticated Little People that there really is something that can give them comfort: either God or personal agency.

In a new post at BackReAction called “Limits of Reductionism,” Sabine Hossenfelder, a theoretical physicist and a fellow at at the Frankfurt Institute for Advanced Studies, tries to save free will in a weird and unconvincing way—indeed, even she doesn’t appear convinced by her lucubrations. (The post is a précis of a longer, prize-winning essay she wrote called “The case for strong emergence.“)

In short, Hossenfelder’s thesis is this: she is a physical determinist, which appears to buttress the incompatibilism of (a), but nevertheless maintains that there just could be a singularity in the nature of physical law, so that although humans are made of molecules that obey the laws of physics, one simply can’t extrapolate those laws up to human behavior because there is a “singularity” that precludes such extrapolationism. In other words, at some point physical law resets itself, and that point occurs below the complexity of the human brain.

Most people, including Hossenfelder, accept that while we may not be able to predict higher-order phenomena like human choice from the laws of physics, it must be consistent with the laws of physics. It is this consistency that Hossenfelder says might not obtain. And if that’s not true, then poof!—we could have free will. Or so she suggests.

Now Hossenfelder is neither a compatibilist nor a dualist, as she makes clear in her BackReAction essay; rather, she appears to be a physical determinist who believes that there are at least two sets of physical laws, one of which somehow gives us real free will. Some quotes:

Her rejection of compatibilism, with which I agree:

Now, there are a lot of people who want you to accept watered-down versions of free will, eg that you have free will because no one can in practice predict your behavior, or because no one can tell what’s going on in your brain, and so on. But I think this is just verbal gymnastics. If you accept that the current theories of particle physics are correct, free will doesn’t exist in a meaningful way.

The dependence of hard determinism on physical reductionism (my emphasis):

That is as long as you believe – as almost all physicists do – that the laws that dictate the behavior of large objects follow from the laws that dictate the behavior of the object’s constituents. That’s what reductionism tells us, and let me emphasize that reductionism is not a philosophy, it’s an empirically well-established fact. It describes what we observe. There are no known exceptions to it.

And we have methods to derive the laws of large objects from the laws for small objects. In this case, then, we know that predictive laws for human behavior exist, it’s just that in practice we can’t compute them. It is the formalism of effective field theories that tells us just what is the relation between the behavior of large objects and their interactions to the behavior of smaller objects and their interactions.

But Hossenfelder, as she says above accepts as a “fact” pure reductionism since we have no counterexamples:

There are a few examples in the literature where people have tried to find systems for which the behavior on large scales cannot be computed from the behavior at small scales. But these examples use unrealistic systems with an infinite number of constituents and I don’t find them convincing cases against reductionism.

Nevertheless (and I admit that what she’s pondering may be above my pay grade), Hossenfelder finds a way to posit the possibility of “free will” by imagining a singularity in the extrapolation of small-scale physical forces, so one not only can’t predict large-scale phenomena from small-scale ones, but also conclude that large-scale phenomena need not be consistent with the laws of physics governing small entities like particles:

It occurred to me some years ago, however, that there is a much simpler example for how reductionism can fail. It can fail simply because the extrapolation from the theory at short distances to the one at long distances is not possible without inputting further information. This can happen if the scale-dependence of a constant has a singularity, and that’s something which we cannot presently exclude.

With singularity I here do not mean a divergence, ie that something becomes infinitely large. Such situations are unphysical and not cases I would consider plausible for realistic systems. But functions can have singularities without anything becoming infinite: A singularity is merely a point beyond which a function cannot be continued.

I do not currently know of any example for which this actually happens. But I also don’t know a way to exclude it.

Well, she’s positing a singularity for which there is no evidence. Why should we take it seriously? It is as if we posit that every four billion years the laws of physics that govern the motion of the planets are suspended for one second—a singularity in time. We have no evidence for that, either, so why take it seriously? Since we cannot “exclude” her supposition, or mine, why should we take them seriously? We cannot absolutely exclude the singularity in planetary motion that I just mentioned, just as we can’t exclude the existence of an invisible tooth fairy. But why do we even need to think about them? Note again that Hossenfelder admits that there is no evidence for her singularity.

Indeed, I’d maintain that we have evidence against it. After all, the behavior of macro objects in space, like rockets or the ageing of humans within them, shows no such singularity: such motion can be predicted by the same laws that govern small molecules. Further, even “macro” behavior of humans, in terms of the firing of neurons, our physiology and biochemistry, and so on, can be reduced to the laws of chemistry, which themselves are consistent with the laws of physics. So if the behavior of our neurons and our innards show no such singularities, why does Hossenfeld imagine that a singularity would apply to human behavior, which, as far as we can see, can be reduced to the material structure of our brain?

At the end Hossenfelder pulls her free-will rabbit out of a hat for which we have no evidence. Note her last sentence, in which she implies that people WANT to believe in nonreductionist free will, which is sort of a form of dualism. Hossenfelder’s dualism is not the invocation of supernatural forces or numinous “will” alongside physical law, but a dualism of the laws of physics themselves (my emphasis):

Now consider you want to derive the theory for the large objects (think humans) from the theory for the small objects (think elementary particles) but in your derivation you find that one of the functions has a singularity at some scale in between. This means you need new initial values past the singularity. It’s a clean example for a failure of reductionism, and it implies that the laws for large objects indeed might not follow from the laws for small objects.

It will take more than this to convince me that free will isn’t an illusion, but this example for the failure of reductionism gives you an excuse to continue believing in free will.

Just like redefining “God” as “the Universe” or “love” gives us an excuse to continue believing in God!

Further, as far as I can see (and again I confess my failure to grasp how this “singularity” works), a new set of physical laws that begins somewhere above the agglomeration of molecules into organisms is still physical law. So how does that give us agency or freedom in the sense that most people construe free will: as a dualistic form of overriding physical law with our brains? A physical law gives us no agency or freedom, no matter on which scale it obtains.

Readers are welcome to enlighten me, and to attempt to show others in simple language how Hossenfelder’s speculation allows us TRUE free will (the could-have-done-otherwise kind). I don’t get it myself.

By the way, since Hossenfelder doesn’t accept compatibilism, please don’t argue for compatibilism in the comments. We’re concerned here with her own hypothesis, which is explicitly non-compatibilistic.

h/t: John

Did Hawking have polio rather than ALS?

March 19, 2018 • 2:15 pm

As we all know, Stephen Hawking is a medical anomaly, for he lived for over half a century with amyotrophic lateral sclerosis (ALS)—a disease that usually kills you within just a few years of diagnosis. As far as I know, he had the disease for longer than any human in history.

But did he really have ALS?

The Torygraph has a new article, based on a physician’s letter sent to to the Financial Times that after some effort, I finally found unpaywalled. Here it is (I think the first sentence is an unintended double entendre):

Well, this dude is a physician, and what do I know? But my impression of polio was that it does most of its damage at the outset, and doesn’t get progressively worse over decades, as Hawking’s illness seems to have done. Not that his polio—if that’s what he had—could have been ameliorated, but didn’t doctors think of that? And there must surely be a test to see if you have a virus versus ALS.

Perhaps Hawking was simply an outlier: a very rare case of hyper-longevity that has been seen in other fatal diseases. (Steve Gould’s cure of mesothelioma is similar.)

Well, it’s not of great import what disease killed Hawking; what I found more interesting was this article, also in the Torygraph (click on screenshot to see it).

An excerpt:

A final theory explaining how mankind might detect parallel universes was completed by Stephen Hawking shortly before he died, it has emerged.

Colleagues have revealed the renowned theoretical physicist’s final academic work was to set out the groundbreaking mathematics needed for a spacecraft to find traces of multiple big bangs.

Currently being reviewed by a leading scientific journal, the paper, named A Smooth Exit from Eternal Inflation, may turn out to be Hawking’s most important scientific legacy.

Fellow researchers have said that if the evidence which the new theory promises had been discovered before Hawking died last week, it may have secured the Nobel Prize which had eluded him for so long.

The problem with the idea of a multiverse, an idea that fascinates me, is that it seemed largely untestable. Hawking’s paper implies that this might not be the case:

Carlos Frenk, professor of cosmology at Durham University, told The Sunday Times: The intriguing idea in Hawking’s paper is that [the multiverse] left its imprint on the background radiation permeating our universe and we could measure it with a detector on a spaceship.

“These ideas offer the breathtaking prospect of finding evidence for the existence of other universe.”

We shall see. This is above my pay grade, so watch our Official Website Physicist™ Sean Carroll’s website for updates. His latest post is a nice summary of Hawking’s scientific contributions.

 

h/t: Hempenstein

Philip Goff returns with panpsychism: now claims that a non-goddy “conscious Universe” explains the “fine-tuning” of physical constants permitting life

February 11, 2018 • 11:30 am

I’ve written two critical posts about the ideas of Philip Goff (a philosophy professor at Central European University in Budapest): here and here. In both places (Aeon and NPR, respectively), Goff argues for “panpsychism”—the idea that in some sense the entire Universe is conscious. He waffles on exactly how that consciousness is manifested, or where it comes from, but in a new piece in Aeon magazine, “Is the Universe a conscious mind?“, Goff not only continues his daft arguments, but now claims that a conscious Universe is the best explanation for the “fine-tuning” of the physical constants that make life on Earth possible.

Let us put aside the contentious claim that the laws of physics are fine-tuned for life, since we just don’t know anything beyond the fact that the constant permit life. Goff says that there are three explanations why we are lucky enough to live in a universe where the constants of physics enable us to contemplate our luck: a beneficent being who made the laws, panpsychism, or the multiverse.  He neglects two other explanations: we’re just lucky, or that there is some reason we don’t understand why physical constants have to take the form they do.

Goff says that panpsychism is the best explanation because theism is afflicted with the problem of evil, which has no clear solution (true!), and the multiverse hypothesis fails —or so he says—because consciousness in a multiverse is more likely to be instantiated in a Boltzmann brain—a conscious “thing” that formed physically in the universe without evolution—than in evolved creatures that developed consciousness. Conscious evolved creatures, he implies, are much rarer than Boltzmann brains, so he accepts Roger Penrose’s argument that:

 . . . by far the most common kind of observer [in the multiverse] would be a ‘Boltzmann’s brain’: a functioning brain that has by sheer fluke emerged from a disordered universe for a brief period of time. If Penrose is right, then the odds of an observer in the multiverse theory finding itself in a large, ordered universe are astronomically small. And hence the fact that we are ourselves such observers is powerful evidence against the multiverse theory.

I doubt that someone like Sean Carroll would agree with that.

I’m not that familiar with Penrose, though I know his ideas aren’t popular, and I know that some readers are familiar with them. But this doesn’t seem a knockdown argument to me. If consciousness evolved even once in a near-infinite number of universes, then the relative likelihood  Boltzmann brains versus evolved brains seems irrelevant. But perhaps I misunderstand the argument.

But I do contest Goff’s claim that the universe has a kind of consciousness, and don’t understand at all how even if there were that consciousness, it would explain “fine tuned” laws of physics. Goff proposes two types of panpsychism:

There are two ways of developing the basic panpsychist position. One is micropsychism, the view that the smallest parts of the physical world have consciousness. Micropsychism is not to be equated with the absurd view that quarks have emotions or that electrons feel existential angst. In human beings, consciousness is a sophisticated thing, involving subtle and complex emotions, thoughts and sensory experiences. But there seems nothing incoherent with the idea that consciousness might exist in some extremely basic forms. We have good reason to think that the conscious experience of a horse is much less complex than that of a human being, and the experiences of a chicken less complex than those of a horse. As organisms become simpler, perhaps at some point the light of consciousness suddenly switches off, with simpler organisms having no experience at all. But it is also possible that the light of consciousness never switches off entirely, but rather fades as organic complexity reduces, through flies, insects, plants, amoeba and bacteria. For the micropsychist, this fading-while-never-turning-off continuum further extends into inorganic matter, with fundamental physical entities – perhaps electrons and quarks – possessing extremely rudimentary forms of consciousness, to reflect their extremely simple nature.

Yes, but surely consciousness requires some kind of neurological substrate, and at some point on the journey from humans to quarks, that substrate disappears completely. What kind of consciousness, then, does a photon have, and how is it formed? He never says. Nor does he discuss that idea that consciousness could be an emergent property of life when it’s reached a certain stage of neurological complexity, and need not be manifested on the scale of particles—just as “wetness” need not be manifested on the scale of a single molecule of water. It takes quite a few of them. Wetness is not a property of an individual molecule, but appears when you get a bunch of them together, and is consonant with the laws of physics.

In the end, though, Goff accepts a different form of “holistic” panpsychism:

However, a number of scientists and philosophers of science have recently argued that this kind of ‘bottom-up’ picture of the Universe is outdated, and that contemporary physics suggests that in fact we live in a ‘top-down’ – or ‘holist’ – Universe, in which complex wholes are more fundamental than their parts. According to holism, the table in front of you does not derive its existence from the sub-atomic particles that compose it; rather, those sub-atomic particles derive their existence from the table. Ultimately, everything that exists derives its existence from the ultimate complex system: the Universe as a whole.

. . . If we combine holism with panpsychism, we get cosmopsychism: the view that the Universe is conscious, and that the consciousness of humans and animals is derived not from the consciousness of fundamental particles, but from the consciousness of the Universe itself. This is the view I ultimately defend in Consciousness and Fundamental Reality.

The cosmopsychist need not think of the conscious Universe as having human-like mental features, such as thought and rationality. Indeed, in my book I suggested that we think of the cosmic consciousness as a kind of ‘mess’ devoid of intellect or reason. However, it now seems to me that reflection on the fine-tuning might give us grounds for thinking that the mental life of the Universe is just a little closer than I had previously thought to the mental life of a human being.

But if this cosmopsychism has no mental-like features, why and how would it “fine tune” the universe for organic life? A “mess” couldn’t do that. And what, exactly, does he mean by cosmopsychism?   In the end, Goff has to accept something like a God, a powerful conscious entity that has a purpose and resolve to fine-tune the laws of physics. The only difference between the Abrahamic God and Goff’s “conscious universe” is that the latter isn’t as powerful. I quote:

But the cosmopsychist has a way of rendering axiarchism intelligible, by proposing that the mental capacities of the Universe mediate between value facts and cosmological facts. On this view, which we can call ‘agentive cosmopsychism’, the Universe itself fine-tuned the laws in response to considerations of value. When was this done? In the first 10-43 seconds, known as the Planck epoch, our current physical theories, in which the fine-tuned laws are embedded, break down. The cosmopsychist can propose that during this early stage of cosmological history, the Universe itself ‘chose’ the fine-tuned values in order to make possible a universe of value.

. . .How are we to think about the laws of physics on this view? I suggest that we think of them as constraints on the agency of the Universe. Unlike the God of theism, this is an agent of limited power, which explains the manifest imperfections of the Universe. The Universe acts to maximise value, but is able to do so only within the constraints of the laws of physics.

Well, I thought the laws of physics were what was to be explained by the Big Non-Goddy Brain, so it appears that Goff is begging the question. The laws, he says, are already there, and impose constraints on the Universe Brain, so how can they be tweaked for life? At this point the argument appears to vanish up its own fundament, but Goff continues the obscurantism:

Having said that, the second and final modification we must make to cosmopsychism in order to explain the fine-tuning does come at some cost. If the Universe, way back in the Planck epoch, fine-tuned the laws to bring about life billions of years in its future, then the Universe must in some sense be aware of the consequences of its actions. This is the second modification: I suggest that the agentive cosmopsychist postulate a basic disposition of the Universe to represent the complete potential consequences of each of its possible actions. In a sense, this is a simple postulation, but it cannot be denied that the complexity involved in these mental representations detracts from the parsimony of the view.

That’s putting it mildly! But Goff still thinks that an aware Universe wanted to see life evolve over billions of years, and thus twiddled with the laws of physics to do so (while itself constrained by those same laws), and that is more parsimonious than the multiverse or a theistic God. But what is the mechanism of this fine tuning? How does it work?

In the end, the best answer to “why is the universe fine tuned for life” seems to be “We don’t know if it is, and even if it is, there are non-panpsychic and non-supernatural explanations for which there is some evidence. But in the end, we don’t know how to answer this question yet.”

I’m surprised that anybody buys this kind of stuff, because it’s really a form of sophisticated-sounding woo. I guess it gives people solace that there’s Something Bigger Than Us Out There. But why on Earth would Aeon publish two articles about this?

Well, here’s one possibility: a disclaimer at the end of Goff’s piece:

This essay was made possible through the support of a grant from Templeton Religion Trust to Aeon and a separate grant from the Templeton funded‘Pantheism and Panentheism’ project to the author. The opinions expressed in this publication are those of the author(s) and do not necessarily reflect the views of Templeton Religion Trust.

Yep, Templeton again! But what does it mean that they made this essay possible? Did they pay Goff to write it, or Aeon to publish it, or was it simply part of Goff’s Templeton-funded work? Who knows? But it’s useful to know that Aeon is well ensconced in Templeton’s deep pockets. Caveat emptor!

On the page listing its sponsors, Aeon notes only one “corporate” sponsor:

I suspect Goff’s pieces are two of the “articles and videos bringing to public view important research and deep, new thinking about soceity, religion, and individual development. Oh, those Big Questions!

All I know is that we have two essays on woo at Aeon, which itself is funded by Templeton, and one at NPR; and a competent physicist could take them all apart with ease. Eight words would suffice: “This is all pure speculation unsupported by evidence.”

Philip Goff

New evidence for the multiverse—and its implications

December 10, 2017 • 9:00 am

As skeptical as I am, I think the contemplation of the multiverse is an excellent opportunity to reflect on the nature of science and on the ultimate nature of existence: why we are here…. In looking at this concept, we need an open mind, though not too open. It is a delicate path to tread. Parallel universes may or may not exist; the case is unproved. We are going to have to live with that uncertainty. Nothing is wrong with scientifically based philosophical speculation, which is what multiverse proposals are. But we should name it for what it is.

— George Ellis, Scientific American, Does the Multiverse Really Exist?

Well, Ellis’s uncertainty may not be permanent. This short film, on the “skydivephil” playlist, presents what they say is evidence for a multiverse. It was sent to me by reader Phil, who I believe is the eponymous creator .

A multiverse is a collection of all multiple, parallel universes; and in the set taken together, a whole panoply of different things happen: many alternative outcomes are instantiated somewhere. The idea of a multiverse first came from Erwin Schrödinger, and for a long time physicists thought that a multiverse was possible but impossible to test, as there was no way we could detect the presence of universes other than ours. The Wikipedia link two sentences prior gives a good summary, as does the video at the bottom.

Now, according to this video, we’ve gotten some evidence for the multiverse, though our Official Website Physicist™ notes (see below) that the new evidence isn’t terribly decisive. The evidence adduced is cosmic inflation, but not just that: eternal cosmic inflation, in which space grows forever. One of the implications of eternal inflation is, according to some (but not all) physicists, the multiverse.

The Physics Man who presents the results below is George Efstathiou, a British physicist at Cambridge.

When I saw this, realizing that it was above my pay grade, I wrote to Sean Carroll, our Official Website Physicist™, asking him this:

Does eternal inflation really constitute evidence for a multiverse? I know you favor multiverses, but I want to know how strong the evidence is. If you want to give me a quote to post, I’d be delighted to do that, but the most important thing is that I understand what this is about.
Sean responded, and I quote him with permission:
Of course it depends on what you mean by “evidence.” In a Bayesian sense, yes: there is experimental evidence that favors inflation (e.g., in temperature fluctuations in the cosmic microwave background), and theory predicts that most inflationary models lead to eternal inflation and a multiverse, so in that sense there is evidence for a multiverse. But not in a direct, empirical sense, of course: everything we see in the observable universe is also completely compatible with ours being the only universe. And even the indirect evidence is quite weak; we don’t know for sure whether inflation happened, nor if it really does create a multiverse. So one’s credences for or against the multiverse shouldn’t be very close to 0% or 100%, they should be somewhere in between.
 The YouTube notes present a similar caveat:
A note of caution. In our opinion inflation is the dominant paradigm for early universe cosmology and most experts in inflationary cosmology seem to agree it leads to a multiverse. Does the mounting evidence for inflation then mean we should accept the multiverse? Well, inflation has passed every test to date but there is still one last hurdle and it may fail at this last test. It’s also possible that we haven’t understood inflation correctly. We need to wait and see if more data can give us a firmer picture of these fascinating questions. Whilst the evidence for inflation and the multiverse then may not be strong enough to call them facts, the statement that there is no evidence at all for these concepts looks dubious.
 Finally, here’s a list proponents and skeptics from Wikipedia, and there are Big Names on both sides:

Proponents of one or more of the multiverse hypotheses include Stephen Hawking, Brian Greene, Max Tegmark, Alan Guth, Andrei Linde, Michio Kaku, David Deutsch, Leonard Susskind, Alexander Vilenkin, Yasunori Nomura, Raj Pathria, Laura Mersini-Houghton, Neil deGrasse Tyson, and Sean Carroll.

Scientists who are generally skeptical of the multiverse hypothesis include: Steven Weinberg, David Gross, Paul Steinhardt, Neil Turok, Viatcheslav Mukhanov, Michael S. Turner, Roger Penrose, George Ellis, Joe Silk, Carlo Rovelli, Adam Frank, Marcelo Gleiser, Jim Baggott, and Paul Davies.

Now the multiverse has lots of implications for our views of physics, philosophy, and biology. Depending on how you conceive of a multiverse (and there are apparently several ways it could be), the anthropic principle—that the laws of physics seem “fine tuned” for our existence—is simply a result of different universes having different laws of physics, and the one with the “right” laws is the one that is ours, the one that allowed life to evolve. This, of course, blows the “fine-tuning” argument, and its supposed use as evidence for God, out the window. There are, of course, other implications for stuff like quantum entanglement, Schrödinger’s Cat, and other physical puzzles: many different outcomes would be realized in one universe or another. The cat would be dead in some universes, but alive in others.

Further, it means that the evolution of humans was inevitable somewhere. In one of those universes that permitted the evolution of life, it was inevitable that a thinking hominin would evolve. That, too, is evidence against theistic arguments—made famous by Simon Conway Morris—that the evolution of humans, which is taken as inevitable, is evidence for our position as God’s special creatures.

Finally, it may (and I’m not sure about this) constitute evidence for “you can choose” free will: that all possible decisions that could be the outcome of the laws of physics in our brain would be instantiated in some universe. [Rethinking this, I don’t think this buttresses “you can choose otherwise” free will unless it reflects quantum phenomena in the brain, which I don’t think is the case.]

Now I’m just speculating here, and these may not follow from any conception of the multiverse, but from what I’ve heard of the “many worlds” hypothesis, these things are possible.

If you want to watch the entire one-hour video from which the above is an excerpt, I’ve put it below.

University of Chicago “celebrates” the first controlled nuclear fission reaction

December 3, 2017 • 11:00 am

As I mentioned in yesterday’s Hili Dialogue, Sunday was the 75th anniversary of the first controlled nuclear fission reaction, which it took place here at the University of Chicago. On December 2, 1942, in an old racketball court beneath the stands of the Stagg Field football stadium, Chicago Pile-1 was activated by Enrico Fermi and his team, producing gazillions of neutrons from cans of uranium oxide that were allowed to reach critical mass. Wikipedia describes the moment, which lasted less than five minutes:

[On] 2 December 1942, everybody assembled for the experiment. There were 49 scientists present.  Although most of the S-1 Executive Committee was in Chicago, only Crawford Greenewalt was present, at Compton’s invitation.  Other dignitaries present included Szilard, Wigner and Spedding. Fermi, Compton, Anderson and Zinn gathered around the controls on the balcony, which was originally intended as a viewing platform. Samuel Allison stood ready with a bucket of concentrated cadmium nitride, which he was to throw over the pile in the event of an emergency. The startup began at 09:54. Walter Zinn removed the zip, the emergency control rod, and secured it.  Norman Hilberry stood ready with an axe to cut the scram line, which would allow the zip to fall under the influence of gravity.[95][96] While Leona Woods called out the count from the boron trifluoride detector in a loud voice, George Weil, the only one on the floor, withdrew all but one of the control rods. At 10:37 Fermi ordered Weil to remove all but 13 feet (4.0 m) of the last control rod. Weil withdrew it 6 inches (15 cm) at a time, with measurements being taken at each step.

The process was abruptly halted by the automatic control rod reinserting itself, due to its trip level being set too low. At 11:25, Fermi ordered the control rods reinserted. He then announced that it was lunch time.

The experiment resumed at 14:00. Weil worked the final control rod while Fermi carefully monitored the neutron activity. Fermi announced that the pile had gone critical (reached a self-sustaining reaction) at 15:25. Fermi switched the scale on the recorder to accommodate the rapidly increasing electrical current from the boron trifluoride detector. He wanted to test the control circuits, but after 28 minutes, the alarm bells went off to notify everyone that the neutron flux had passed the preset safety level, and he ordered Zinn to release the zip. The reaction rapidly halted. The pile had run for about 4.5 minutes at about 0.5 watts. Wigner opened a bottle of Chianti, which they drank from paper cups.

Compton notified Conant by telephone. The conversation was in an impromptu code:

Compton: The Italian navigator has landed in the New World.
Conant: How were the natives?

Chianti! There might as well have been fava beans.  This of course led to the atomic bomb (I’m not going to argue whether or not our dropping it twice on Japan was the right thing to do), and the nuclear powderkeg that is today’s world.  One could make a case that nuclear fission also has benefits, like the generation of nuclear power. But we’ll never know whether fission was a good or bad thing until humanity is gone, with or without a nuclear annihilation.

But somehow the celebration of nuclear fission by calling attention to atomic bombs seems, well, a bit weird. Yes, we must be mindful of the mixed legacy of nuclear fission, but showing a bomb?

For instance, Henry Moore’s famous sculpture just a block from where I sit, called “Nuclear Energy” certainly represents a mushroom cloud. It sits atop the exact spot where Fermi’s group created the fission reaction.

Henry Moore: “Nuclear Energy,” 1967, placed near the site of the first self-sustaining chain reaction, Dec. 2, 1942, University of Chicago campus, on Ellis.

What is even weirder is that often Japanese tourists descend on that sculpture in packs, with tour buses disgorging people who can’t wait to pose for selfies in front of the bomb statue. Are they mindful of the irony? It always gives me a shiver to see it, and I see it often.

Yesterday and the day before, the University celebrated the Fermi team’s work with a series of lectures, symposia, and, to cap the “celebration”,  a daytime fireworks display by Cai Gu-Quian, a 59 year old Chinese artist who lives in New York and stages ephemeral art based on fireworks and gunpowder. For yesterday’s grand finale, right across the street from me, he created a colorful mushroom cloud firework that went off over Regenstein Library. Here’s a video of Gu-Quian describing the event, which begins with 75 peals of a tower bell at Rockefeller chapel. If you want to skip the preliminaries and the bells, start at 7:21.

The show is over in about 30 seconds, but I suspect someone paid the artist a lot of dosh to create and stage this “performance art.” Note the clapping afterwards. Cai as well as other University people explain it further in the University announcement of the events:

Cai Guo-Qiang said: “In the 1990s, I used black gunpowder to create mushroom clouds, humankind’s most iconic visual symbol for the 20th century. These mushroom clouds formed part of my Projects for Extraterrestrials. Today, the color mushroom cloud symbolizes the paradoxical nature of employing nuclear energy: Who is it for?”

“The work dramatizes the creative and destructive forces of nuclear fission,” said Steward [Laura Steward, curator at the Smart Museum of Art on campus]. “It takes the iconic shape of nuclear energy’s most destructive form and animates it with color as a profound symbol of creativity and peace.”

“Cai’s artwork reflects the yin-yang nature of the December 2, 1942 experiment’s impact. Its dualism places medicine and energy on one side, and weapons and massive destruction on the other side,” said Young-Kee Kim, the Louis Block Distinguished Service Professor of Physics and the College and chair of the Department of Physics at the University of Chicago.

There’s that dualism again. Where’s the medicine and energy bit? Is that the fireworks themselves, which have nothing to do with nuclear energy?

Now maybe I’m curmudgeonly about this, but do we really need to celebrate nuclear fission by showing mushroom clouds? Yes, it’s a complex legacy, but it’s like celebrating chemistry by displaying cans of Zyklon-B. I found this “highlight” of the events here bizarre and tasteless.

Here’s Robert Oppenheimer describing the reaction of himself and others who witnessed the successful Trinity bomb test on July 16, 1945 in New Mexico. Oppenheimer was the head of the Los Alamos lab that created the first atomic bomb—the one dropped on Hiroshima and Nagasaki.  There wasn’t much celebration then. (Oppenheimer’s quote of course has become quite famous.)

I have landed. . . to find quantum quackery

November 16, 2017 • 4:00 pm

. . . in Houston, that is. The George Bush airport is HUGE and not pleasant. Next I have a 2-hour flight to Puebla.

I have no time for posting, but here’s something to examine very critically. The famed physicist Roger Penrose, over at the Daily Galaxy, says he has a reliable physical mechanism for producing a soul. Have a look at the piece and then have at it. I’m told by a friend that this stuff is all over social media, since it has the imprimatur of a genuine Famous Scientist.

One quote:

While scientists are still in heated debates about what exactly consciousness is, the University of Arizona’s Stuart Hameroff and British physicist Sir Roger Penrose conclude that it is information stored at a quantum level. Penrose agrees –he and his team have found evidence that “protein-based microtubules—a structural component of human cells—carry quantum information— information stored at a sub-atomic level.”

Penrose argues that if a person temporarily dies, this quantum information is released from the microtubules and into the universe. However, if they are resuscitated the quantum information is channeled back into the microtubules and that is what sparks a near death experience. “If they’re not revived, and the patient dies, it’s possible that this quantum information can exist outside the body, perhaps indefinitely, as a soul.

Not only that, but others (who are unnamed) agree:

Researchers from the renowned Max Planck Institute for Physics in Munich are in agreement with Penrose that the physical universe that we live in is only our perception and once our physical bodies die, there is an infinite beyond. Some believe that consciousness travels to parallel universes after death.

Well, all I can say is that there is no evidence I’m aware of that quantum-mechanical phenomena operate in the brain, much less that they play a role in consciousness and memory. And even if they did, how does any “information” in the brain stay together as a coherent unit after death? In what form does it exist? (It can’t be particles or forces, as Sean Carroll has shown.)  And how does it get into another body?

Oy gewalt! How does a renowned physicist who did important work get involved with this stuff? But I’m just a poor country biologist. I wish I had Sean Carroll here behind this sign. . .

Gravity waves: a reader’s take

November 5, 2017 • 9:30 am

I’m busy much of today, but have a few contributions from others to show.

I thought I had posted on the discovery of gravity waves from the LIGO Project when it happened, but I can’t seem to find the post. (I did mention the award of this year’s Nobel Prize in physics to its discoverers.) At any rate, you can read about that discovery, which detected the almost-undetectable but predicted waves coming from the collision of two black holes, at the website of Official Website Physicist™ Sean Carroll. The detection of those waves, and the apparatus required to do it, is to my mind one of the great intellectual achievements of our species.

This came to mind when I got an email yesterday from reader Tim Anderson, who regularly sends us photos of animals and stars. Here’s what he said (the emphasis is mine):

I don’t know if you read the story about the detection of the radiation from the collapse of two neutron stars. Seventy observatories around the world collected data from all wavelengths between gamma and infrared after LIGO observed the gravitational waves coming out of the event. We can see the event happening in real time.
But here is the most astonishing measurement. LIGO measures gravitational waves via a metric called “peak strain”. Imagine an object that is one metre long and that is aligned along the wave path from the neutron star-pair collapse. The “peak strain” measures how much spacetime distorts the object from end to end as the wave passes through.
LIGO measured the peak strain to be 1 X 10 ^ – 22 m. That is less than one quarter of the diameter of a proton. And we measured it!
And here is another astonishing thing. The lead paper covering the discovery has 4500 listed authors (approximately one-third of the professional astrophysicists on our planet). They are listed in alphabetical order, so this paper will be forever known as Abbott et al.
Wikipedia has a nice article about the LIGO project, which has now detected gravity waves five times, and using two independent stations 1865 miles apart:
Each detector has two arms, each 4 km long. Here’s a photo of the one at Hanford, and you can read more about this apparatus and the experiment at the LIGO site.
The paper, which does indeed have 4500 authors, can be seen here (pdf here), and if you want the full list of names, click on this icon after the title:
Here’s just part of it. It’s so long that there’s even a Coyne in the list (no relation):