A Hypothesis on Interdisciplinary Perceptions

Postulate (Sturgeon’s Law): 90% of everything is crud.

Observation: Part of being educated in a field is learning how to filter out the crud produced in it—the work which is slapdash, too banal to spend brain-time on, fundamentally misguided, boring. This “learning how to filter” includes both recognizing bad work quickly when one sees it and taking advantage of existing social mechanisms for winnowing intellectual wheat from chaff.

Result: When Alice, trained in one field (say, physics) looks over into another (e.g., philosophy), she’s likely to hit crud. If this happens a few times over, Alice is apt to form a low opinion of the other field, a low opinion which is in a way justifiable but which in a deeper sense is misleading. This process repeats with Bob, Carol, etc.; by the time we get to Xenia, there is a notion afloat in one field that the other isn’t much good, leading to reciprocal enmity from the other.

Observation 2: If Amelie is formally trained in one field (say, pure mathematics) and accomplishes something legitimate in another (perhaps she pens an evocative new translation of the poems of Ryōkan), then the fact that she jumped discliplinary boundaries will be less remarked upon than if her effort failed. The departmental affiliation of a competent worker is easily forgotten, but that of a grandiose blowhard is easily remembered.

Overall result: In a subtle way, the world gets worse.

Epistricted Trits

In quantum mechanics, we are always calculating probabilities. We get results like, “There is a 50% chance this radioactive nucleus will decay in the next hour.” Or, “We can be 30% confident that the detector at position X will register a photon.” But the nature and origin of quantum probabilities remains obscure. Could it be that there are some kind of “gears in the nucleus,” and if we knew their alignment, we could predict what would happen with certainty? Fifty years of theorem-proving have made this a hard position to maintain: quantum probabilities are more exotic than that.

But what we can do is reconstruct a part of quantum theory in terms of “internal gears.” We start with a mundane theory of particles in motion or switches having different positions, and we impose a restriction on what we can know about the mundane goings-on. The theory which results, the theory of the knowledge we can have about the thing we’re studying, exhibits many of the same phenomena as quantum physics. It is clearly not the whole deal: For example, quantum physics offers the hope of making faster and more powerful computers, and the “toy theory” we’ve cooked up does not. But the “toy theory” can include many of the features of quantum mechanics deemed “mysterious.” In this way, we can draw a line between “surprising” and “truly enigmatic,” or to say it in a more dignified manner, between weakly nonclassical and strongly nonclassical.

The ancient Greek for “knowledge” is episteme (επιστημη) and so a restriction on our knowledge is an epistemic restriction, or epistriction for short.

A trit system is one where every degree of freedom has three possible values. Looking at Figure 4 of Spekkens’ “Quasi-quantization: classical statistical theories with an epistemic restriction,” we see that the valid states of an epistricted trit follow the same pattern as the SIC-allied Mutually Unbiased Bases of a quantum trit. But that is a story for another day.

Google Scholar Irregularities

Google Scholar is definitely missing citations to my papers.

The cited-by results for “Some Negative Remarks on Operational Approaches to Quantum Theory” [arXiv:1401.7254] on Google Scholar and on INSPIRE are completely nonoverlapping. Google Scholar can tell that “An Information-Theoretic Formalism for Multiscale Structure in Complex Systems” [arXiv:1409.4708] cites “Eco-Evolutionary Feedback in Host–Pathogen Spatial Dynamics” [arXiv:1110.3845] but not that it cites My Struggles with the Block Universe [arXiv:1405.2390]. Meanwhile, the SAO/NASA Astrophysics Data System catches both.

This would be a really petty thing to complain about, if people didn’t seemingly rely on such metrics.

EDIT TO ADD (17 November 2014): Google Scholar also misses that David Mermin cites MSwtBU in his “Why QBism is not the Copenhagen interpretation and what John Bell might have thought of it” [arXiv:1409.2454]. This maybe has something to do with being worse at detecting citations in footnotes than in endnotes.

Adventures in the Sophomoric

Yesternight, I went memory-road-tripping through my blog archives. One of the things I realized, apart from how amazingly enthusiastic I was for the blogging form back in 2007, was how much I reviled my sophomore-year university physics classes. At the time, they were unpleasant; in retrospect, they were deleterious.

The worst was the relativity class, which had most of the interesting stuff dug out, and hot air pumped in to fill it out to a semester. Also a waste of time was the first semester of quantum mechanics—we had three, and the latter two were great. That is actually a topic where a three-fold division could make sense. One could have, for example, a semester on the basic formalism, a semester on symmetries and exactly solvable systems and then a term covering approximation methods. But that’s not what we did. Instead, the first term was “intuition building,” which translates to “let’s plod through differential equations over and over and over again, because learning any oh-so-much-harder math would be too much for your young brains.” Mixed in with that was a rather bog-standard “physicist’s history of physics,” which was as usual too inevitably misleading to be worth bothering with. The time period in question is fascinating to me, as is our professional mythologizing about it. The textbook cardboard we got couldn’t do the subject justice.

And another thing: ditch the requirement of going to the Math Dept for a differential equations class. That class sucked. Again, pretty much inevitably. I’d say it was doomed from the get-go, i.e., failure was ensured by the choice of topics and level of coverage. (All I remember from that semester was the professor’s claim that the Laplace transform takes you into a world where everything is yellow. I still don’t know what that means. Everything I was supposed to learn in that class, I picked up elsewhere and elsewhen.) A much better alternative would be an in-house class on mathematical methods. It’d slot neatly into the same place in the curriculum, even. And there are good books to teach out of! Also, for the love of Gauss, don’t rely on Matlab. Real programming languages exist and are at least as easy to introduce. If you’re going to be gung-ho about Technologically Enhancing the Active Learning in your classrooms, you might as well teach some skills which physicists could actually use.

(Said in a tone of voice suggesting that one might eventually have dinosaurs on one’s dinosaur tour.)

Multiscale Structure via Information Theory

We have scienced:

B. Allen, B. C. Stacey and Y. Bar-Yam, “An Information-Theoretic Formalism for Multiscale Structure in Complex Systems” [arXiv:1409.4708].

We develop a general formalism for representing and understanding structure in complex systems. In our view, structure is the totality of relationships among a system’s components, and these relationships can be quantified using information theory. In the interest of flexibility we allow information to be quantified using any function, including Shannon entropy and Kolmogorov complexity, that satisfies certain fundamental axioms. Using these axioms, we formalize the notion of a dependency among components, and show how a system’s structure is revealed in the amount of information assigned to each dependency. We explore quantitative indices that summarize system structure, providing a new formal basis for the complexity profile and introducing a new index, the “marginal utility of information”. Using simple examples, we show how these indices capture intuitive ideas about structure in a quantitative way. Our formalism also sheds light on a longstanding mystery: that the mutual information of three or more variables can be negative. We discuss applications to complex networks, gene regulation, the kinetic theory of fluids and multiscale cybernetic thermodynamics.

There’s much more to do, but for the moment, let this indicate my mood:

Dirac, Pauli and You

Here is Paul Dirac in October 1927:

If we are honest — and scientists have to be — we must admit that religion is a jumble of false assertions, with no basis in reality. The very idea of God is a product of the human imagination. It is quite understandable why primitive people, who were so much more exposed to the overpowering forces of nature than we are today, should have personified these forces in fear and trembling. But nowadays, when we understand so many natural processes, we have no need for such solutions. I can’t for the life of me see how the postulate of an Almighty God helps us in any way. What I do see is that this assumption leads to such unproductive questions as why God allows so much misery and injustice, the exploitation of the poor by the rich and all the other horrors He might have prevented. If religion is still being taught, it is by no means because its ideas still convince us, but simply because some of us want to keep the lower classes quiet. Quiet people are much easier to govern than clamorous and dissatisfied ones. They are also much easier to exploit. Religion is a kind of opium that allows a nation to lull itself into wishful dreams and so forget the injustices that are being perpetrated against the people. Hence the close alliance between those two great political forces, the State and the Church. Both need the illusion that a kindly God rewards — in heaven if not on earth — all those who have not risen up against injustice, who have done their duty quietly and uncomplainingly. That is precisely why the honest assertion that God is a mere product of the human imagination is branded as the worst of all mortal sins.

To which Wolfgang Pauli is said to have replied,
Continue reading Dirac, Pauli and You