[Fis] New Year Lecture wrap-up
Dear Hans, Thank you very much again for your lecture and your subsequent comments and replies. I dare posting a new comment as an aftermath to your wrap-up and to Pedro's official closure. But I am sure you agree with me, that the matter cannot be settled yet and that a continuation of the discussion is a sign of the fruitfulness of your lecture. As a matter of fact, when I received Pedro's official closure announcement I was a little disappointed because I had been gathering some evidence in support of a previous comment of mine, which probably was not clear enough. I would not like to bother you any more, but since you mention the usefulness of a philosophical outlook, here is a philosophical observation I was able to find. According to Jules Vuillemin (*Necessity or Contingency*, Stanford CA, CSLI Publications, 1996), “probability in the classical sense,” as is well known, is “relative to our ignorance only” (p. 261), but “probability amplitude is something altogether different” (264). For “when physicists today make reference to [...] probability amplitudes [...] they indeed allude to second order probabilities” (167). Therefore, the distinction “between a probability and a probability amplitude” entails a “new distinction in the history of modal notions,” a distinction that Vuillemin describes in the following way: “Classical physics was content with the opposition 'This particle passes through A' versus 'This particle has the probability π of passing through A'. This opposition has nothing to do with ontology: it incorporates what is due to our ignorance into the determination of natural phenomena. Instead of attributing a property or magnitude to a physical system, we attribute it a disposition or propensity to have that property or magnitude. Probability measures that disposition or propensity that belongs to the system in act. A probability amplitude is something altogether different. We can compare it to an embryonic probability as the inventors of the infinitesimal calculus compared the moment of motion to an embryonic motion that an integration would bring to a state of whole motion. But the comparison limps. For the probability amplitude, which is generally a complex quantity, does not figure among the elements of reality. To obtain a probability we must multiply two conjugated probability amplitudes. This means that, when we attribute that amplitude to a system, it is attributed neither as an actual property or magnitude nor as an actual disposition or propensity to having such property or magnitude, but as a purely virtual disposition or propensity to having it. The second- order potentiality, as it were, thus put into play is no longer the measure of an ignorance that might have some chance of being only provisional. It is physical. It describes nature.” (264-65) This is just the conclusion of a long-winded argument, but if Vuillemin is right, then, the interpretation of a superposition of probability amplitudes cannot be Bayesian, or “relative to our ignorance only.” (261) As S. Barry Cooper observes ( *Definability in the Real Universe*, http://arxiv.org/abs/1109.1416 ), “the Laplacian model has a deeply ingrained hold on the rational mind. For a bromeliad-like late flowering of the paradigm we tend to think of Hilbert and his assertion of very general expectations for axiomatic mathematics. Or of the state of physics before quantum mechanics.” From this point of view, QBism might be described, to use Barry Cooper's own words, as “a defensive response to an uncompleted paradigm change” (p. 4). Kind regards, -dino buzzetti On 18 January 2014 18:47, Hans von Baeyer henrikrit...@gmail.com wrote: Dear Friends: In keeping with the message of my lecture, that knowledge of the world is based on the ensemble of individual experiences, more than on assumed objective, actual properties of an external reality, I will tell you about my experiences of writing and discussing the New Year Lecture. I enjoyed the entire process enormously, and wish once more to applaud Pedro for inventing this new tradition! Even as I started this email I learned something that piqued my interest. Gregory Bateson was quoted: Kant argued long ago that this piece of chalk contains a million potential facts (Tatsachen) but that only a very few of these become truly facts by affecting the behavior of entities capable of responding to facts. Google.de informed me that Tatsache is probably an 18th century translation of the English matter of fact. Tat is a deed, a factum, something done or performed, while Sache means a thing or a matter. This tenuous etymology connects factuality with action rather than with some intrinsic essence. Kant's words affecting, behavior and responding are QBist to the core. More and more I realize that philosophy matters. Chris Fuchs, the chief spokesman for QBism, is among the rare physicists who give credit to philosophers for the contributions
Re: [Fis] New Year Lecture wrap-up
Caro Pedro e cari tutti, questa e-mail dell'egregio Hans von Baeyer mi ha stimolato a segnalare, ancora una volta, quanto sia stato anticipatore il mio pensiero scientifico-economico sull'importanza della legge dell'informazione a partire, ad es.,dagli inizi degli anni Ottanta. Sia chiaro, non rivendico nè presumo niente, bensì da poverino esponenziale come mi auto-definisco sento tutto il piacere bambino di portare alla Vostra conoscenza che sul processo di tras-in-form-azione ho scritto e pubblicato più di una dozzina di libri. Qualcuno di essi l'ho inviato al carissimo Pedro che mi auguro continui a tenermi non solo nella mente, ma anche nel cuore. Grazie e saluti augurali nel nome del Signore mio e di tutti, credenti e non credenti. Francesco Rizzo, già professore di Economia e organizzazione aziendale nella Facoltà di Ingegneria di Catania. 2014/1/18 Hans von Baeyer henrikrit...@gmail.com Dear Friends: In keeping with the message of my lecture, that knowledge of the world is based on the ensemble of individual experiences, more than on assumed objective, actual properties of an external reality, I will tell you about my experiences of writing and discussing the New Year Lecture. I enjoyed the entire process enormously, and wish once more to applaud Pedro for inventing this new tradition! Even as I started this email I learned something that piqued my interest. Gregory Bateson was quoted: Kant argued long ago that this piece of chalk contains a million potential facts (Tatsachen) but that only a very few of these become truly facts by affecting the behavior of entities capable of responding to facts. Google.de informed me that Tatsache is probably an 18th century translation of the English matter of fact. Tat is a deed, a factum, something done or performed, while Sache means a thing or a matter. This tenuous etymology connects factuality with action rather than with some intrinsic essence. Kant's words affecting, behavior and responding are QBist to the core. More and more I realize that philosophy matters. Chris Fuchs, the chief spokesman for QBism, is among the rare physicists who give credit to philosophers for the contributions they make to natural science. In return he hopes that they will listen to physicists who bring news from the furthest reaches of nature. My most intense experience in connection with the New Year Lecture was the writing of it. The first challenge was brevity: The letter I have written today is longer than usual because I lacked the time to make it shorter quipped Blaise Pascal. In order to introduce QBism to you, I had to explain the Q and the B. How to do that within the allotted length? The distinction between Bayesian and frequentist probability is an old subject among mathematicians, so I was able to steal from them. (Schreiben ist Borgen, writing is borrowing, according to the aphorist G.C. Lichtenberg.) But in order to talk about the Q, I had to show succinctly what's so special about quantum mechanics. At this point I was considerably aided by the GHZ prediction and its fairly recent corroboration, because, unlike all previous experiments, GHZ is a one-shot deal, rather than a subtle statistical effect. Like finding a single white raven to falsify the claim that all ravens are black. But even so, although I could easily demonstrate the WRONG classical prediction, I was not able to show those of you who are not trained in theoretical physics how the correct quantum mechanical prediction for GHZ comes about. Unfortunately I would need a semester for that! In any case, by keeping to the prescribed format of the lecture, I was able to clarify my own thinking and to streamline my presentation of the unfamiliar topic. My timing was very fortunate in that two unusually accessible articles about QBism appeared in November and December 2013 -- both available for free at arxiv.org. (ID numbers 1311.5253v1 and 1312.7825.) What a welcome coincidence! It reassured me that the topic I had chosen for my lecture is emerging from its niche in quantum foundations research and slowly seeping out into the broader community. From the subsequent discussion I discovered several important things that are new to me. I learned that there is the possibility, by means on non-Kolmogorovian probabilities, to avoid the troublesome certainty of probability 0 and 1 -- in particular via Logic in Reality. I learned about the interesting concept of feed-forward, in contrast to feedback, which corrects for disruptions of a system BEFORE the disrupting influence kicks in. (In order to do that, the mechanism has to make use of an accurate model of the system's performance, so that it can PREDICT how the system will react. I think it's an exaggeration to call this maneuver inverting the cause-and-effect sequence, but it comes close.) I learned about instrumentalism, and will try to understand how it relates to pragmatism.
[Fis] New Year Lecture wrap-up
Dear Friends: In keeping with the message of my lecture, that knowledge of the world is based on the ensemble of individual experiences, more than on assumed objective, actual properties of an external reality, I will tell you about my experiences of writing and discussing the New Year Lecture. I enjoyed the entire process enormously, and wish once more to applaud Pedro for inventing this new tradition! Even as I started this email I learned something that piqued my interest. Gregory Bateson was quoted: Kant argued long ago that this piece of chalk contains a million potential facts (Tatsachen) but that only a very few of these become truly facts by affecting the behavior of entities capable of responding to facts. Google.de informed me that Tatsache is probably an 18th century translation of the English matter of fact. Tat is a deed, a factum, something done or performed, while Sache means a thing or a matter. This tenuous etymology connects factuality with action rather than with some intrinsic essence. Kant's words affecting, behavior and responding are QBist to the core. More and more I realize that philosophy matters. Chris Fuchs, the chief spokesman for QBism, is among the rare physicists who give credit to philosophers for the contributions they make to natural science. In return he hopes that they will listen to physicists who bring news from the furthest reaches of nature. My most intense experience in connection with the New Year Lecture was the writing of it. The first challenge was brevity: The letter I have written today is longer than usual because I lacked the time to make it shorter quipped Blaise Pascal. In order to introduce QBism to you, I had to explain the Q and the B. How to do that within the allotted length? The distinction between Bayesian and frequentist probability is an old subject among mathematicians, so I was able to steal from them. (Schreiben ist Borgen, writing is borrowing, according to the aphorist G.C. Lichtenberg.) But in order to talk about the Q, I had to show succinctly what's so special about quantum mechanics. At this point I was considerably aided by the GHZ prediction and its fairly recent corroboration, because, unlike all previous experiments, GHZ is a one-shot deal, rather than a subtle statistical effect. Like finding a single white raven to falsify the claim that all ravens are black. But even so, although I could easily demonstrate the WRONG classical prediction, I was not able to show those of you who are not trained in theoretical physics how the correct quantum mechanical prediction for GHZ comes about. Unfortunately I would need a semester for that! In any case, by keeping to the prescribed format of the lecture, I was able to clarify my own thinking and to streamline my presentation of the unfamiliar topic. My timing was very fortunate in that two unusually accessible articles about QBism appeared in November and December 2013 -- both available for free at arxiv.org. (ID numbers 1311.5253v1 and 1312.7825.) What a welcome coincidence! It reassured me that the topic I had chosen for my lecture is emerging from its niche in quantum foundations research and slowly seeping out into the broader community. From the subsequent discussion I discovered several important things that are new to me. I learned that there is the possibility, by means on non-Kolmogorovian probabilities, to avoid the troublesome certainty of probability 0 and 1 -- in particular via Logic in Reality. I learned about the interesting concept of feed-forward, in contrast to feedback, which corrects for disruptions of a system BEFORE the disrupting influence kicks in. (In order to do that, the mechanism has to make use of an accurate model of the system's performance, so that it can PREDICT how the system will react. I think it's an exaggeration to call this maneuver inverting the cause-and-effect sequence, but it comes close.) I learned about instrumentalism, and will try to understand how it relates to pragmatism. I was surprised when the conversation on the list veered from probability and epistemology to communication and information. But I shouldn't have been. The QBist point of view divides science into two realms. On the one hand each individual agent assembles the totality of her experiences (experimenting, reading, talking, calculating...) into a web of probability assignments that is as coherent and comprehensive as possible. That's the easy part, and, as usual, physicists have picked it as their domain. But the hard part is the effort of agents to correlate their private experiences -- i.e. to communicate with each other in order to develop a common scientific worldview. Agent A's description of an experience serves as input for updating B's personal probability assignments via Bayes' law. And this is done through language as well as math. Niels Bohr more clearly than any of the other pioneers of quantum mechanics realized the importance of language
