Category: Physics

Time at Work

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Time is a strange concept according to several strains of science and related philosophical concerns. We have this everyday medium-macroscopic set of ideas about how there is an undiscovered country of the future, a now we are experiencing, and a past that we remember or model based on accumulated historical facts. When we venture into extensions of conceptual ideas like an infinite past or sequenced events we deploy reasoning about what their properties might be by excluding contradictory compositions of properties and using other kinds of limiting semantics to constrain a mental model of those concepts.

But that isn’t the weirder stuff. The weirder stuff is the result of a collision of measurement and scientific theory.

Take, for instance, the oft-described reversibility of Newtonian physics. We have an equation for an object’s motion that can be run backward in time. But entropy in large ensembles of things in motion is not reversible because of some odd property of energy dissipation into the environment that arises because of micro-interactions. Some say this creates an “arrow of time” in the face of these reversible equations.

But this is an odd way of characterizing mathematical statements that represent the uniformity of physical interactions. The idea of “reversibility” is just a matter of a computational representation of processes that do always flow forward in time. Running t from 0 to -∞ in an equation has no real relationship to any physical phenomena. So the reversibility of mathematical forms is just an interesting fact.

We can bind up space and time, as well, which also provokes feelings of incongruity when we start to talk about gravitational effects on relative elapsed time, or relative speed effects.… Read the rest

A Learning Smorgasbord

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Compliments of a discovery by Futurism, the paper The Autodidactic Universe by a smorgasbord of contemporary science and technology thinkers caught my attention for several reasons. First was Jaron Lanier as a co-author. I knew Jaron’s dad, Ellery, when I was a researcher at NMSU’s now defunct Computing Research Laboratory. Ellery had returned to school to get his psychology PhD during retirement. In an odd coincidence, my brother had also rented a trailer next to the geodesic dome Jaron helped design and Ellery lived after my brother became emancipated in his teens. Ellery may have been his landlord, but I am not certain of that.

The paper is an odd piece of kit that I read over two days in fits and spurts with intervening power lifting interludes (I recently maxed out my Bowflex and am considering next steps!). It initially has the feel of physicists trying to reach into machine learning as if the domain specialists clearly missed something that the hardcore physical scientists have known all along. But that concern dissipated fairly quickly and the paper settled into showing isomorphisms between various physical theories and the state evolution of neural networks. OK, no big deal. Perhaps they were taken by the realization that the mathematics of tensors was a useful way to describe network matrices and gradient descent learning. They then riffed on that and looked at the broader similarities between the temporal evolution of learning and quantum field theory, approaches to quantum gravity, and cosmological ideas.

The paper, being a smorgasbord, then investigates the time evolution of graphs using a lens of graph theory. The core realization, as I gleaned it, is that there are more complex graphs (visually as well as based on the diversity of connectivity within the graph) and pointlessly uniform or empty ones.… Read the rest

A Pause in Attention

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I routinely take a pause in what I am doing to reflect on my goals and what I’ve learned. I’m sure you do too. I had been listening to the recorded works of Jean Sibelius and Carl Nielsen, but am now on to Sir Edward Elgar and Josef Suk. Billie Eilish and Vampire Weekend didn’t last long. I gave up on my deep learning startup to pursue another, less abstract technology. I revamped this site. I put trail running on pause and have been lifting weights more. I shifted writing efforts to a new series centered on manipulating animal physiologies for war and espionage.

These pauses feel like taking an expansive stretch after sitting still for a long period; a reset of the mental apparatus that repositions the mind for a new phase. For me, one take away from recent events, up to and including the great pause of the coronavirus pandemic, is a reconsideration of the amount of silly and pointless content we absorb. Just a few examples: The drama of Twitter feuds among the glitterati and the political class, cancel culture, and shaming. The endless technology, photography, audiophile, fashion, and food reporting and communal commenting that serves to channel our engagement with products and services. Even the lightweight philosophizing that goes with critiques of tradition or society has the same basic set of drivers.

What’s shared among them is the desire for attention, an intellectual posturing to attract and maintain the gaze of others. But it does have a counterpoint, I believe, in a grounding in facts, reason, and a careful attention to novelty. The latter may be a bit hard to pin down, though. It is easy to mistake randomness or chaos for novelty.… Read the rest

Deep Learning with Quantum Decoherence

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Getting back to metaphors in science, Wojciech Zurek’s so-called Quantum Darwinism is in the news due to a series of experimental tests. In Quantum Darwinism (QD), the collapse of the wave function (more properly the “extinction” of states) is a result of decoherence from environmental entanglement. There is a kind of replication in QD, where pointer states are multiplied, and then a kind of environmental selection as well. There is no variation per se, however, though some might argue that the pointer states imprinted by the environment are variants of the originals. Still, it makes the metaphor a bit thin at the edges, but it is close enough for the core idea to fit most of the floor-plan of Darwinism. Indeed, some champion it as part of a more general model for everything. Even selection among viable multiverse bubbles has a similar feel to it: some survive while others perish.

I’ve been simultaneously studying quantum computing and complexity theories that are getting impressively well developed. Richard Cleve’s An Introduction to Quantum Complexity Theory and John Watrous’s Quantum Computational Complexity are notable in their bridging from traditional computational complexity to this newer world of quantum computing using qubits, wave functions, and even decoherence gates.

Decoherence sucks for quantum computing in general, but there may be a way to make use of it. For instance, an artificial neural network (ANN) also has some interesting Darwinian-like properties to it. The initial weight distribution in an ANN is typically a random real value. This is designed to simulate the relative strength of neural connections. Real neural connections are much more complex than this, doing interesting cyclic behavior, saturating and suppressing based on neurotransmitter availability, and so forth, but assuming just a straightforward pattern of connectivity has allowed for significant progress.… Read the rest

Metaphors as Bridges to the Future

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David Lewis’s (I’m coming to accept this new convention with s-ending possessives!) solution to Putnam’s semantic indeterminacy is that we have a network of concepts that interrelate in a manner that is consistent under probing. As we read, we know from cognitive psychology, texts that bridge unfamiliar concepts from paragraph to paragraph help us to settle those ideas into the network, sometimes tentatively, and sometimes needing some kind of theoretical reorganization as we learn more. Then there are some concepts that have special referential magnetism and are piers for the bridges.

You can see these same kinds of bridging semantics being applied in the quest to solve some our most difficult and unresolved scientific conundrums. Quantum physics has presented strangeness from its very beginning and the various interpretations of that strangeness and efforts to reconcile the strange with our everyday logic remains incomplete. So it is not surprising that efforts to unravel the strange in quantum physics often appeal to Einstein’s descriptive approach to deciphering the strange problems of electromagnetic wave propagation that ultimately led to Special and then General Relativity.

Two recent approaches that borrow from the Einstein model are Carlo Rovelli’s Relational Quantum Mechanics and David Albert’s How to Teach Quantum Mechanics. Both are quite explicit in drawing comparisons to the relativity approach; Einstein, in merging space and time, and in realizing inertial and gravitational frames of reference were indistinguishable, introduced an explanation that defied our expectations of ordinary, Newtonian physical interactions. Time was no longer a fixed universal but became locked to observers and their relative motion, and to space itself.

Yet the two quantum approaches are decidedly different, as well. For Rovelli, there is no observer-independent state to quantum affairs.… Read the rest

Causing Incoherence to Exist

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I was continuing discussion on Richard Carrier vs. the Apologists but the format of the blog posting system made a detailed conversation difficult, so I decided to continue here. My core argument is that the premises of Kalam are incoherent. I also think some of the responses are as well.

But what do we mean by incoherent?

Richard interpreted that to mean logically impossible, but my intent was that incoherence is a property of the semantics of the words. Statements are incoherent when they don’t make sense or only make sense with a very narrow and unwarranted reading of the statement. The following argument follows a fairly standard analytic tradition analysis of examining the meaning of statements. I am currently fond of David Lewis’s school of thought on semantics, where the meaning of words exist as a combination of mild referential attachment, coherence within a network of other words, and, importantly, some words within that network achieve what is called “reference magnetism” in that they are tied to reality in significant ways and pull at the meaning of other words.

For instance, consider Premise 1 of a modern take on Kalam:

All things that begin to exist have a cause.

OK, so what does begin to exist mean? And how about cause? Let’s unpack “begin to exist,” first. We might say in our everyday world of people that, say, cars begin to exist at some point. But when is that point? For instance, is it latent in the design for the car? Is it when the body panels are attached on the assembly line? Is it when the final system is capable of car behavior? That is, when all the parts that were in fact designed are fully operational?… Read the rest

Two Points on Penrose, and One On Motivated Reasoning

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Sir Roger Penrose is, without doubt, one of the most interesting polymaths of recent history. Even where I find his ideas fantastical, they are most definitely worth reading and understanding. Sean Carroll’s Mindscape podcast interview with Penrose from early January of this year is a treat.

I’ve previously discussed the Penrose-Hameroff conjectures concerning wave function collapse and their implication of quantum operations in the micro-tubule structure of the brain. I also used the conjecture in a short story. But the core driver for Penrose’s original conjecture, namely that algorithmic processes can’t explain human consciousness, has always been a claim in search of support. Equally difficult is pushing consciousness into the sphere of quantum phenomena that tend to show random, rather than directed, behavior. Randomness doesn’t clearly relate to the “hard problem” of consciousness that is about the experience of being conscious.

But take the idea that since mathematicians can prove things that are blocked by Gödel incompleteness, our brains must be different from Turing machines or collections of them. Our brains are likely messy and not theorem proving machines per se, despite operating according to logico-causal processes. Indeed, throw in an active analog to biological evolution based on variation-and-retention of ideas and insights that might actually have a bit of pseudo-randomness associated with it, and there is no reason to doubt that we are capable of the kind of system transcendence that Penrose is looking for.

Note that this doesn’t in any way impact the other horn of Penrose-Hameroff concerning the measurement problem in quantum theory, but there is no reason to suspect that quantum collapse is necessary for consciousness. It might flow the other way, though, and Penrose has created the Penrose Institute to look experimentally for evidence about these effects.… Read the rest

Theoretical Reorganization

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Sean Carroll of Caltech takes on the philosophy of science in his paper, Beyond Falsifiability: Normal Science in a Multiverse, as part of a larger conversation on modern theoretical physics and experimental methods. Carroll breaks down the problems of Popper’s falsification criterion and arrives at a more pedestrian Bayesian formulation for how to view science. Theories arise, theories get their priors amplified or deflated, that prior support changes due to—often for Carroll—coherence reasons with other theories and considerations and, in the best case, the posterior support improves with better experimental data.

Continuing with the previous posts’ work on expanding Bayes via AIT considerations, the non-continuous changes to a group of scientific theories that arrive with new theories or data require some better model than just adjusting priors. How exactly does coherence play a part in theory formation? If we treat each theory as a binary string that encodes a Turing machine, then the best theory, inductively, is the shortest machine that accepts the data. But we know that there is no machine that can compute that shortest machine, so there needs to be an algorithm that searches through the state space to try to locate the minimal machine. Meanwhile, the data may be varying and the machine may need to incorporate other machines that help improve the coverage of the original machine or are driven by other factors, as Carroll points out:

We use our taste, lessons from experience, and what we know about the rest of physics to help guide us in hopefully productive directions.

The search algorithm is clearly not just brute force in examining every micro variation in the consequences of changing bits in the machine. Instead, large reusable blocks of subroutines get reparameterized or reused with variation.… Read the rest

Indifference and the Cosmos

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I am a political independent, though that does not mean that I vote willy-nilly. I have, in fact, been reliably center left for most of my adult life, save one youthfully rebellious moment when I voted Libertarian, more as a statement than a commitment to the principles of libertarianism per se. I regret that vote now, given additional exposure to the party and the kinds of people it attracts. To me, the extremes of the American political system build around radical positions, and the increasingly noxious conspiracy theories and unhinged rhetoric is nothing like the cautious, problem-solving utopia that might make me politically happy, or at least wince less.

Some might claim I am indifferent. I would not argue with that. In the face of revolution, I would require a likely impossible proof of a better outcome before committing. How can we possibly see into such a permeable and contingent future, or weigh the goods and harms in the face of the unknown? This idea of indifference, as a tempering of our epistemic insights, serves as a basis for an essential idea in probabilistic reasoning where it even has the name, the principle of indifference, or, variously, and in contradistinction with Leibniz’s principle of sufficient reason, the principle of insufficient reason.

So how does indifference work in probabilistic reasoning? Consider a Bayesian formulation: we inductively guess based on a combination of a priori probabilities combined with a posteriori evidences. What is the likelihood of the next word in an English sentence being “is”? Indifference suggests that we treat each word as likely as any other, but we know straight away that “is” occurs much more often than “Manichaeistic” in English texts because we can count words.… Read the rest

Gravity and the Dark Star

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I began at 5 AM from the Broomfield Aloft hotel, strategically situated in a sterile “new urban” office park cum apartment complex along the connecting freeway between Denver and Boulder. The whole weekend was fucked in a way: colleges across Colorado were moving in for a Monday start, half of Texas was here already, and most of Colorado planned to head north to the zone of totality. I split off I-25 around Loveland and had success using US 85 northbound through Cheyenne. Continuing up 85 was the original plan, but that fell apart when 85 came to a crawl in the vast prairie lands of Wyoming. I dodged south and east, then, (dodging will be a continuing theme) and entered Nebraska’s panhandle with middling traffic.

I achieved totality on schedule north of Scottsbluff. And it was spectacular. A few fellow adventurers were hanging out along the outflow lane of an RV dump at a state recreation area. One guy flew his drone around a bit. Maybe he wanted B roll for other purposes. I got out fast, but not fast enough, and dodged my way through lane closures designed to provide access from feeder roads. The Nebraska troopers were great, I should add, always willing to wave to us science and spectacle immigrants. Meanwhile, SiriusXM spewed various Sibelius pieces that had “sun” in their name, while the Grateful Dead channel gave us a half dozen versions of Dark Star, the quintessential jam song for the band that dates to the early, psychedelic era of the band.

Was it worth it? I think so, though one failed dodge that left me in a ten mile bumper-to-bumper crawl in rural Nebraska with a full bladder tested my faith in the stellar predictability of gravity.… Read the rest