Drawing on a large academic literature in topics like sociology, behavioral economics, anthropology, and psychology, and especially the (generalized) theory of signalling, Robin Hanson has assembled a large toolbox for systemically understanding hypocrisy, i.e., the ways in which people’s actions systematically and selfishly deviate from their verbalized explanations. Although he would be the first to admit that many of these ideas have been discovered and rediscovered repeatedly over centuries (or millennia) with varying degrees of clarity, and although there is much I am not convinced by, I find the general framework deeply insightful, and his presentation to be more clear, analytical, and descriptive (rather than disruptively normative) than other accounts. Most of this I have gathered from his renowned blogging at Overcoming Bias, but I have always wished for a more concise (and high status!) form factor that I could point others to. At long last, Hanson and his co-author Kevin Simler have written a nice book that largely satisfies me: The Elephant in the Brain (Amazon). I highly recommend it.
The reason I title these sorts of blog posts “Comments on…” is so I can present some disorganized responses to a work without feeling like I need to build a coherent thesis or pass overall judgment. I do not summarize the book below, so this post will mostly be useful for people who have read it. (You might think of this as a one-sided book club discussion rather than a book review.) But since I will naturally tend to focus on the places where I disagree with the authors, let me emphasize: the basic ideas of this book strike me as profound and probably mostly true.… [continue reading]
The primary use for my iPad is reading and annotating papers. It’s new secondary use is as a whiteboard during Skype. WebWhiteboard and AWW App both facilitate public whiteboards without needing a login/signup, and work pretty well with your browser on iPad. WebWhiteboard has a limited and dated interface, but is fairly reliable. AWW App has a more modern interface, but seems to have slow/unreliable servers. Then there are a ton of options that require signup, but I don’t know whether any are worth using.
By way of Eric Rogstad and Tyler Cowen is this new-to-me idea: In the same way that, theoretically, the value of fiat currency is set by a given demand for a medium of exchange, the “fundamental” value of a bitcoin might be determined by a given demand for stores of value.
I’ve only used it for a week, but it’s the best PDF reader I’ve experienced for reading academic articles. It’s snappy and reminds me of Chrome when it first came out. Draggable tabs. Split view. Plays well with Zotero. Can easily add native PDF annotation and search through the existing ones. (And it saves annotations fast when you close the file.Competitors either do this slowly or, like Skim, use a non-native annotation format that can’t be read by other PDF readers.a ) The UI for “find” displays a lot of info intuitively.Edit 2018-1-12: And you can search for any unicode character! Really useful for searching a document for math.b Everything is just nicely designed. I haven’t yet run into a limitation on the free version, but it’s worth upgrading to Pro to support the developer (only $20).
Beware that this is the first version following a big re-write of PDF Reader X, and it’s not completely stable. I’ve gotten it to crash a few times, but the developer has been very responsive to feedback and I’d wager on the stability improving soon. (Edit 2018-1-7: After upgrading to the new version, 3.0.20A, a couple weeks ago, I haven’t experienced any crashes. Looks stable.)
I’m advertising Guru because I think the current selection of PDF readers for academic reading is pretty bad.I have no connection to the developer.c I strongly prefer Guru (instability and all) over these other PDF readers on maxOS that I have tried: FoxIt, Preview, Adobe Acrobat Reader, and Skim.… [continue reading]
For several months, Fermat’s Library has offered a Chrome extension called Librarian for browsing PDFs on the arXiv that automatically parses references to clickable journal links and bibtex entries. Very recently they added the ability to publicly comment, visible to anyone else running Librarian. Should be lower friction than commenting on (also excellent) SciRate.
Three weeks into his new job as Arizona’s governor, Doug Ducey made a move that won over Silicon Valley and paved the way for his state to become a driverless car utopia.
It was January 2015 and the Phoenix area was about to host the Super Bowl. Mr. Ducey learned that a local regulator was planning a sting on Lyft and Uber drivers to shut down the ride-hailing services for operating illegally. Mr. Ducey, a Republican who was the former chief executive of the ice cream chain Cold Stone Creamery, was furious.
“It was the exact opposite message we should have been sending,” Mr. Ducey said in an interview. “We needed our message to Uber, Lyft and other entrepreneurs in Silicon Valley to be that Arizona was open to new ideas.” If the state had a slogan, he added, it would include the words “open for business.”
Mr. Ducey fired the regulator who hatched the idea of going after ride-hailing drivers and shut down the entire agency, the Department of Weights and Measures. By April 2015, Arizona had legalized ride-sharing.
In particular, he sketched the essential equivalence between matrix product states (MPS) and restricted Boltzmann machinesThis is discussed in detail by Chen et al. See also good intuition and a helpful physicist-statistician dictionary from Lin and Tegmark.b (RBM) before showing how he and collaborators could train an efficient RBM representations of the states of the transverse-field Ising and XXZ models with a small number of local measurements from the true state.
“There are now five different lines of observational evidence pointing to the existence of Planet Nine,” Konstantin Batygin, a planetary astrophysicist at the California Institute of Technology (Caltech) in Pasadena, said….
…a study that examined the elliptical orbits of six known objects in the Kuiper Belt…all of those Kuiper Belt objects have elliptical orbits that point in the same direction and are tilted about 30 degrees “downward” compared to the plane in which the eight official planets circle the sun…
Using computer simulations of the solar system with a Planet Nine…there should be even more objects tilted a whopping 90 degrees with respect to the solar plane.
[This is akin to a living review, which will hopefully improve from time to time. Last edited 2020-4-8.]
This post will collect some models of decoherence and branching. We don’t have a rigorous definition of branches yet but I crudely define models of branching to be models of decoherenceI take decoherence to mean a model with dynamics taking the form for some tensor decomposition , where is an (approximately) stable orthonormal basis independent of initial state, and where for times and , where is the initial state of and is some characteristic time scale.a which additionally feature some combination of amplification, irreversibility, redundant records, and/or outcomes with an intuitive macroscopic interpretation.
(Note in particular that I am not just listing models for which you can mathematically take a classical limit ( or ) and recover the classical equations of motion; Yaffe has a pleasingly general approach to that task , but I’ve previously sketched why that’s an incomplete explanation for classicality.)
I have the following desiderata for models, which tend to be in tension with computational tractability:
A senior colleague asked me for thoughts on this paper describing a single-preferred-branch flavor of quantum mechanics, and I thought I’d copy them here. Tl;dr: I did not find an important new idea in it, but this paper nicely illustrates the appeal of Finkelstein’s partial-trace decoherence and the ambiguity inherent in connecting a many-worlds wavefunction to our direct observations.
We propose a method for finding an initial state vector which by ordinary Hamiltonian time evolution follows a single branch of many-worlds quantum mechanics. The resulting deterministic system appears to exhibit random behavior as a result of the successive emergence over time of information present in the initial state but not previously observed.
We start by assuming that a precise wavefunction branch structure has been specified. The idea, basically, is to randomly draw a branch at late times according to the Born probability, then to evolve it backwards in time to the beginning of the universe and take that as your initial condition. The main motivating observation is that, if we assume that all branch splittings are defined by a projective decomposition of some subsystem (‘the system’) which is recorded faithfully elsewhere (‘the environment’), then the lone preferred branch — time-evolving by itself — is an eigenstate of each of the projectors defining the splits. In a sense, Weingarten lays claim to ordered consistency [arxiv:gr-qc/9607073] by assuming partial-trace decoherenceNote on terminology: What Finkelstein called “partial-trace decoherence” is really a specialized form of consistency (i.e.,… [continue reading]
LaTeX in comments
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