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James Putnam: ""Of course, Lorentz' formula "yields results that are independent of..." in The Disintegration of the...

Eckard Blumschein: "Of course, Lorentz' formula "yields results that are independent of..." in The Disintegration of the...

Gary Simpson: "Pentcho, I'm looking forward to your essay. I've already submitted mine..." in FQXi Essay Contest 2016:...

Pentcho Valev: "Deduction: The Only Method in Theoretical Physics Sabine Hossenfelder:..." in FQXi Essay Contest 2016:...

Eric ------: "It seems that Max Tegmark is equating mathematics with patterns of..." in Tegmark's Mathematical...

kurt stocklmeir: "Around 1990 I said time particles and space particles are spin 1 tachyons. ..." in Alternative Models of...

Steve Dufourny: "We can unify G h and c,we can also make convergences between the..." in Alternative Models of...

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Riding the Rogue Quantum Waves
Could giant sea swells help explain how the macroscopic world emerges from the quantum microworld? (Image credit: MIT News)

Rescuing Reality
A "retrocausal" rewrite of physics, in which influences from the future can affect the past, could solve some quantum quandaries—saving Einstein's view of reality along the way.

Untangling Quantum Causation
Figuring out if A causes B should help to write the rulebook for quantum physics.

In Search of a Quantum Spacetime
Finding the universe's wavefunction could be the key to understanding the emergence of reality.

Collapsing Physics: Q&A with Catalina Oana Curceanu
Tests of a rival to quantum theory, taking place in the belly of the Gran Sasso d'Italia mountain, could reveal how the fuzzy subatomic realm of possibilities comes into sharp macroscopic focus.

December 9, 2016

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FQXi Essay Contest 2016: Wandering Towards a Goal
By BRENDAN FOSTER • Dec. 2, 2016 @ 17:46 GMT

In physics we tend to stick to asking what happened, how did it happen? We like to describe, usually in minute details. We like to use the smallest possible components, “building blocks”, “unit cells".

But there are other ways to think about physical reality. We can ask why did it happen? Was there a reason, or a reason it seems to have a reason? We can go beyond describing and try to explain, motivate. We can see beyond parts and think in terms of systems and wholes.

This shift in thought brings us to the next $40,000 FQXi essay contest, brought to you with our partners at The Peter and Patricia Gruber Foundation!

This year’s theme is: Wandering Towards a GoalHow can mindless mathematical laws give rise to aims and intentions?

One way to think of physics is as a set of mathematical laws of dynamics. These laws provide predictions by carrying conditions at one moment of time inexorably into the future. But many phenomena admit another description – sometimes a vastly more useful one – in terms of long-term, large-scale goals, aims, and intentions.

The motion of the most basic particle can be described by the action of forces moment by moment or as the attempt to extremize an action integral, calculated over the particle’s entire path throughout time. Many-body systems can seem hopelessly complex when looked at in terms of their constituents' detailed dynamic motions, but neatly elegant when viewed as attempting to minimize energy or maximize entropy. Living systems efficiently organize their simplest components with the intricate aims of survival, reproduction, and other biological ends; and intelligent systems can employ a panoply of physical effects to accomplish many flexibly chosen goals.

How does this work? How do goal-oriented systems arise, and how do they exist and function in a world that we can describe in terms of goal-free mathematical evolution?

Relevant essays might address questions such as:

* How did physical systems that pursue the goal of reproduction arise from an a-biological world?

* What general features — like information processing, computation, learning, complexity thresholds, and/or departures from equilibrium — allow (or proscribe) agency?

* How are goals (versus accomplishments) linked to “arrows of time”?

* What separates systems that are intelligent from those that are not? Can we measure this separation objectively and without requiring reference to humans?

* What is the relationship between causality – the explanation of events in terms of causes – and teleology – the explanation of events in terms of purposes?

* Is goal-oriented behavior a physical or cosmic trend, an accident or an imperative?

We are accepting entries from now until March 3, 2017, with winners announced in June. The contest rules will operate as in past contests. Please read the contest pages for instructions and full rules.

The contest is open to anyone, so please share this info with everyone. Good luck and good writing!
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The Disintegration of the Moon; Art & Jazz Meet Physics; (Reverse) Debates on Consciousness; & more…from the 5th FQXi Meeting
By ZEEYA MERALI • Nov. 11, 2016 @ 20:19 GMT

Credit: Jayne Tollaksen & Francesca Vidotto
While you weren’t looking, more content from FQXi’s 5th International meeting in Banff has started to trickle through, including a bit more audio and a lot more video. Thanks for your patience.

First up, Brendan Foster and I recorded a special edition of the podcast in Banff on creativity and science. We were lucky enough to be joined by science fiction author Neal Stephenson, who chatted about how he came up with the idea for his latest bestseller, Seveneves—a story about the aftermath of the moon’s disintegration—and how authors tread the line between respecting established science and pushing into more speculative realms.

Free Podcast

Science & Creativity: Conversation with bestselling science fiction author Neal Stephenson, artist Jayne Tollaksen, and musical physicists Ian Durham, Stephon Alexander & Brendan Foster. With Zeeya Merali.


Go to full podcast

We also spoke with artist Jayne Tollaksen, who recently ran an art-physics program at the Perimeter Institute in Waterloo, Ontario. This involved co-creating a series of portraits of various physicists (and FQXi members), in which the physicists themselves took an active role in producing the pieces. The image on the top right is a portrait of Francesca Vidotto, by Tollaksen and Vidotto. You can hear Tollaksen talking about how these portraits were made, and the influence they had on the physicists who took part—providing the scientist with new insights into their modes of thinking, the creative process, and their physics research. At the end of the collaboration, each physicist was invited to describe their experiences. Here are Vidotto’s words, written for the project:

My hands are offering you my collaboration and all my passion for the mysteries of the universe. From my hands, my craftsmanship, a whole universe can take shape. In the theory I work with, Loop Quantum Gravity, the whole universe collapses and then bounces back into the expanding universe that we observe today. The geometry at the bounce is a quantum geometry, described mathematically  by a net of lines connecting the quanta of spacetime. Modeling the shape of the universe requires craftsmanship—a mathematical craftsmanship—but comes always first from a vision, very much in the same way of an artistic creation.

Also joining the discussion were a couple of FQXi’s favorite physicist-musicians, Stephon Alexander and Ian Durham. (Brendan is a musician too.) Alexander, a cosmologist and jazz saxophonist, recently published a terrific book—part popular physics, part musical memoir—called The Jazz of Physics. One connection between the two disciplines that Alexander highlights is the importance of improvisation, something we commonly associate with jazz, but perhaps don’t normally think of in terms of the everyday workings of physicists.

Having pondered the links between art, music and science, the next natural question for me was whether we can (and should) change the way that physics and science is taught in schools and universities, to embrace the creative process more openly. One theme that Durham, Alexander and Tollaksen all came back to was the importance of making mistakes in order to progress, and how we need to give students space to “fail” —because this is such a crucial part of the creative learning process. What are your thoughts?

Even at the professional level, scientists often feel stifled and lack the confidence to put forward ideas that may, at first, seem absurd, for fear of appearing ridiculous. Of course, FQXi is always happy to help scientists get comfortable with being laughed at. As a case in point, I’ll leave you with a video of a debate on consciousness between philosopher and cognitive scientist David Chalmers, who formulated the “hard problem of consciousness” (the problem of explaining how we have phenomenal experiences), and physicist Carlo Rovelli, who takes a more materialistic stance. Here they are arguing about the role of consciousness in physics, but with a twist: Chalmers and Rovelli must passionately argue their opponents’ position, as if it were their own—while wearing bear hats and carrying hockey sticks.


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Koalas, Quantum Mechanics and My Role as the 2016 Women in Physics Lecturer in Australia
By CATALINA OANA CURCEANU • Nov. 2, 2016 @ 18:22 GMT

On the Women in Physics Lecture tour
This August, I was honored to make my first visit to Australia as the winner of the 2016 Women in Physics International Award of the Australian Institute of Physics (AIP). I gave a series of lectures across Australia, holding about 30 seminars and conferences in a number of universities, research centers, colleges and public sites. The series started in Tasmania and moved to Sydney (where I lectured at the astronomical observatory), the Wollongong Science Centre, Brisbane, Adelaide, Perth, Canberra and Melbourne. A real tour de force which was possible only due to the support from the AIP colleagues who organized the tour in the best way.

While lecturing across Australia I met children as young as six, but I also met with interested audiences of all ages, including some poets that took part in my conferences. I talked about stars, black holes, quantum mechanics and about my research activities at the DAFNE collider in Frascati (LNF-INFN) and at the Gran Sasso underground laboratory, including my FQXi financed project about testing collapse models of quantum theory. (You can read more about what collapse models are and my research in my FQXi Q&A.)

One of the goals of the tour was lecturing about science to girls and encouraging them to pursue a career in science—a goal which was achieved, considering the girls’ overwhelming enthusiasm and participation in the meetings. One of the most successful activities was the Girls in Physics Breakfast, which involved—despite the early start at 7 am—more than 100 girls from 20 different Melbourne colleges. They asked so many questions about my life and about "what it is like to be a scientist."

Maybe the most interesting question during the tour was asked to me by an enthusiast 8 years old boy—he wanted to know "How big is space?"

I met so many girls and boys wishing to study science; looking into their eyes I saw a universe of beautiful possibilities, I saw the future.

I also visited wonderful laboratories in universities and science centres in the towns I visited and discussed with Australian colleagues about physics, research activities and possibilities to collaborate in the near future both on technological developments (detector systems and their possible use in fundamental science and applications) and new experiments at the underground laboratory near Melbourne in construction. Why not to test the collapse models in the Southern Hemisphere as well?

I also understood what makes Australia such a wonderful country: people with different cultural backgrounds, coming from all places in the world, all of them proud to be Australians! I believe that we, the rest of the world, can only learn the lesson Australia teaches us!

I didn’t have the chance to meet many koalas or kangaroos, but I met a lot of enthusiastic people, who love science and consider it a fundamental resource for our society.

Still a connection was established between koalas and…quantum mechanics: in a girls’ college in Melbourne, where I was lecturing about the Schroedinger’s cat paradox and future quantum technologies, I had the surprise to receive from the girls, after my presentation, a very nice little box. Opening it I found a koala toy—the girls told me they wanted to use the koala instead of the cat to express the “measurement problem” which they had studied to prepare for our discussions.
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Defining the Observer
By IAN DURHAM • Oct. 5, 2016 @ 20:03 GMT

The main theme of August's FQXi conference was centered around the physics of the observer and so, in wrapping up our discussion of the conference, it remains to be asked if any progress was made toward a better understanding of the concept. As with just about any conference or meeting of researchers from such diverse backgrounds, it is natural to expect that each of us came in to the conference with out own opinions, ideas, and, yes, biases. It's difficult to say if anyone actually changed their mind about anything or was swayed by a reasonable but opposing argument, as a result of this conference.

Of course, science is not based on opinion. The final arbiter of science must always be carefully constructed experiment. Certainly there are some, including a few attendees of this conference, who have suggested that science, and most notably physics, has moved into the post-experiment era in which an elegant mathematical description is all that is required to prove a physical "truth." As someone who wrote his doctoral thesis on one failed attempt to reduce physics to a purely deductive exercise, I can say that this argument is actually nothing new. Physicists have occasionally entertained this idea at one time or another throughout the past four centuries. In some sense, Hilbert formally challenged physicists to do exactly this---axiomatize physics---in his famous Sixth Problem (though, it should be noted, that his actual statement of the problem can be interpreted as having a narrower focus). Experiment, however, persists as the final arbiter of physical "truth" precisely because it has the most direct connection to our senses which remains the only way in which we directly interact with the world. In other words, we expect science to interpret the world of our experience.

That being said, modern physicists know well that direct experience can often be deceiving. Both relativity and quantum mechanics---the two foundational pillars of modern physics---raise direct issues concerning the role of the observer in our understanding of the world. Indeed, some of these issues have been at the forefront of physics for four centuries. After all, it was Galileo (and not Einstein as many incorrectly believe) who developed the principle of relativity which states that the laws of physics should be the same in all inertial reference frames. Galileo's thought experiment involved someone in a windowless cabin on a ship in calm waters---would that person be able to determine with absolute certainty if they were moving or not? The answer, of course, is no.

The key here is that this says something profound about the nature of the observer---all inertial observers must agree on the laws of physics, though not necessarily on the specific outcomes of individual experiments. In other words, the universe must be self-consistent, i.e. it must operate in the same manner for all inertial observers.

In the quantum realm, however, we learn that the observer can affect the outcome of experiments. Is this a violation of the principle of relativity, then? Not necessarily. The principle simply says that the same rules must apply to all inertial observers. Variation in the outcomes of individual experiments is allowed as long as the rules that led to those results are the same in each case.

And that, right there, is the real key to this entire discussion. Science has very carefully built a structure and methodology for addressing these issues over the course of those same four centuries that has been a consistently reliable predictor of future outcomes. Arguable this methodology---which defines modern science---is the greatest achievement in the history of humanity. One of its hallmarks, particularly in physics, is its emphasis on rigor and clarity (perhaps due to the close ties between physics and mathematics). We need to know what it is that we're talking about otherwise we end up just talking past one another, sometimes without realizing. John Wheeler's argument that we need to move beyond defining things sounds almost Aristotelean in contrast. Indeed, one way in which this grand enterprise we call science has progressed has been by agreeing on definitions and then testing those definitions. In theory, this should lead to further refinement of those definitions. Unfortunately, science, including physics itself, has become fractured enough that universal consensus on some definitions---including "the observer"---is lacking.

A classic example of this that recalls several conversations and exchanges made at the last few FQXi conferences, is the concept of entropy. Despite the fact that Boltzmann and Gibbs clarified the definition of entropy in the 19th century (which Jaynes so elegantly further clarified in the mid-20th century), there are those that persist in defining entropy via a Clausius relation. While such a relation is certainly a valid manner in which to describe certain types of entropy, it is abundantly clear from even a cursory reading of Boltzmann, Gibbs, and Jaynes that such a relation does not work as a universal definition. It is simply a way in which entropy behaves under certain, limiting conditions and tells us nothing about its actual nature.

At any rate, this brings us back to the question at hand. What is an observer? For that matter, what is an event? Does the latter require the former? These were both questions that ostensibly were to be addressed at the conference. In fact an entire session was dedicated solely to the observer. During the Q&A session of the associated panel, Jeremy Butterfield pointed out that modern philosophy, via Frege, Russell, et. al., had established set definitions for many of these "truths," relations, etc. that are generally free from the types of disciplinary bias you get in science. For example, those who prefer to define entropy via a Clausius relation are typically those who work in areas reliant on classical thermodynamics. This comment by Butterfield raises a few interesting points. Notably, it sets a definitive role for philosophy in the advancement of science. Scientists are often dismissive of the role of philosophy, but, just like science, philosophy is not monolithic. While it certainly contains its share of post-modernist rubbish, it also includes some very important and rigorous work including, as Butterfield pointed out, in defining certain important terms used by science. Having these independent, broadly developed ideas and definitions can help to relieve some of the tensions surrounding some of these definitions.

All of this is to say that we still have no consistent definition of an observer, per se. Even Butterfield did not offer one. The session and the subsequent panel did little to clear the fog on this issue, Butterfield's comments notwithstanding. That's not to say that the others didn't offer interesting and cogent opinions. David Wolpert, for instance, suggested that an observer, whatever one is, must be in a non-equilibrium state. While this is an intriguing idea, the other panelists showed no inclination to jump on that bandwagon. (It bears mentioning that, if observers automatically come equipped with a reference frame and since reference frames naturally break some symmetry when they are introduced to a problem, then Wolpert's idea might be the germ of something more generally valid and useful.)

At any rate, Jim Hartle offered up an amusing anecdote at one point that could be a kind of metaphor for the session. He mentioned that Murray Gell-Mann once compared something to "sticking a pin in the I Ching, but no one understood what the hell he meant." This may sound like a harsh indictment of the session, but it shouldn't be taken in that way. In fact, the session had the essence of one of those good, working sessions from legendary physics conferences of old like the Shelter Island Conference in 1947 (which Oppenheimer felt was the best conference he had ever attended). In that sense, the session lent a feeling to the proceedings that this---the FQXi conference---was, first and foremost, a working conference. And that is what makes these conferences so unique. Some of the brightest minds in physics, philosophy, neuroscience, mathematics, biology, computer science, and elsewhere communicate with one another, poking and prodding at the heart of difficult questions, nudging the scientific process along. This is where the real work gets done.
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Defining Existence
By IAN DURHAM • Sep. 15, 2016 @ 19:09 GMT

What exists? On the one hand, this seems like the kind of naval-gazing question that provokes derision and mockery from those more interested in practical matters. I exist, you exist, this blog post exists. It's self-evident, right? Of course one could simply presume that everything they experience is nothing but a dream or illusion and that only they, themselves, actually exist. But solipsism is a useless philosophy when dealing with the IRS, say, or anyone else for that matter. So it may seem to be a silly question to ask.

On the other hand, when one delves into it more than superficially, defining existence turns out to be about as complex as defining consciousness. Putting solipsistic arguments aside, there are some things that quite obviously exist. But then there are grey areas. In my recent blog post on consciousness, I mentioned that there was a good deal of overlap between the nature of consciousness and the nature of existence. Giulio Tononi, as I pointed out, believes that there are gradations to existence that are a result of the causal power of something. I gave the example of a painting that is completed by a painter, but then the painter and painting are immediately engulfed in flames such that no record is left of the painting leaving us wondering if it ever existed in the first place.

At a certain level, it is absurd to think it didn’t exist simply because no record of it was ever made. This is actually just a rehashing of Maxwell’s demon; there is a record of it somewhere in a real universe because the act of painting it increased the entropy of the universe in some manner. A better question (and, truthfully, the real question I have about the painting) is, what became of the information associated with the aesthetic appreciation of that painting?

To put it another way, I can imagine many fanciful things that I know simply cannot exist because they violate the laws of physics: artificial gravitational fields in relatively small, non-rotating spacecraft, spacecraft that make sound in empty space, etc. While they may not be physically realizable, they nevertheless exist in my imagination which, as part of my mind, which very clearly exists. (If you read the article on consciousness, you may recall that this was Tononi’s starting assumption about consciousness.)

In philosophical circles, this is known as ontological commitment and, as the name suggests, refers to a relation between a language and something that is proposed to be “extant” by that language, i.e. something that language says exists. It is generally understood that the “thing” that is proposed to exist does not necessarily have to be physical. One of the earliest and most influential formulations of ontological commitment was given by the philosopher W.V. Quine. What is interesting is that it centers around what can be stated in a formal language. In other words, it would seem to rule out the possibility of the existence of things that are “unspeakable,” i.e. not representable in a formal manner. This is, of course, closely (though not perfectly) aligned with Heidegger’s famous question, ‘What is a thing?’

In recent decades, physicists have even begun to consider the issues of existence and “thingness.” Chris Isham and Andreas Döring, for example, have even ventured so far as to discuss the latter directly in their work on topos theory in physics, something most physicists might be tempted to avoid, at least explicitly. So it is that FQXi convened an entire panel at this year’s conference devoted to discussing the concept of existence.

While Tononi was not actually on the panel himself, he did, as I mentioned, address the issue when he discussed consciousness, equating levels of existence with degrees of causal power: maximal existence is possessed by things with maximal causal power. Though the concept of gradations of existence is missing, Rafael Bousso’s theory of existence could be viewed as philosophically kin to Tononi’s. Bousso makes the claim that the only thing that exists is a particular causal “patch” in spacetime (this is somewhat similar to the concept of a causal “diamond”). It is his view that everything that we can measure is in a particular causal patch and it is meaningless to consider anything else. It might be tempting to think that Bousso’s approach is just a restatement of the hard-line operationalist view that would deny the existence of the moon if no one is looking at it, but I think that would be a mischaracterization. What he is really saying is that it is meaningless to talk about the existence of things that we have no hope of ever measuring. For example, he emphasized that this rules out the existence of a typical multiverse since it isn’t contained within our causal diamond (no word on what his theory might say about Wiseman’s many-interacting worlds hypothesis). The causal patch does contain many possible histories which, I suppose, might make it compatible with some consistent history theories of quantum mechanics. But the causal patch, which appears to be Bousso’s only bound on measurability, is fairly limiting. For example, it conveniently does not rule out the non-measurable aspects of string theory (of which he is a proponent). The fact remains that not all limitations on measurability are necessarily due to the dynamics of space and time.

Some of the questions I have already raised are indicative of the types of problems that the concept of a causal patch does not address. For example, Jenann Ismael asked how we can meaningfully talk about evolving interactions between the mind and the world if the mind is in the world? The more general formulation of this question might be to ask how we can meaningfully talk about interactions between a sub-system with a larger system of which it is a part. But then, as Steve Giddings pointed out, how do we properly define a sub-system?

When polled on the concept of existence, the panel offered a wide array of views, from Carlo Rovelli’s musings about the “existence” of Hamlet, to Laura Mersini-Houghton’s assertion that existence requires an observer. Ismael explicitly mentioned Quine by name, though said her views are a somewhat modified version of his arguments about ontological commitment. Bousso took a slightly different tack when pressed on the topic and said that, ultimately, what matters are the fundamental, base axioms from which everything else can be derived. In my notes, I wrote “I’m surprised to find myself agreeing with Rafael” on this point. But in hindsight I’m not sure why I wrote that since every attempt to axiomatically derive physics has, to date, failed. I wrote my PhD thesis on one such failed attempt (Eddington’s). So I suppose I will fall back on Tononi’s position: I know I exist. Perhaps the rest of you can be derived, but perhaps not.
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