venerdì 5 dicembre 2036

Piero and RQM

Just a couple of links:

1. Me. A post containing and about Nulla imago sine perspectiva (link) in RQM, translated as "No quale without a pointer basis", sci.physics.research, August 30, 2005. NB Qualia (sing. quale) are variously referred to as sensory occurrences, properties of experiences, recognizable qualitative characters of the given (see e.g. this entry in the SEP).
2. Carlo Rovelli, Matteo Smerlak. "On attribue au grand peintre italien Piero della Francesca, maître de la Renaissance et théoricien de la perspective picturale, la formule « Nulla imago sine perspectiva » : pas d'image sans perspective. Eh bien, selon l'interprétation relationnelle, la mécanique quantique montre que ce n'est pas seulement vrai des images, mais de tous les objets physiques." L'erreur d'Einstein, Le monde quantique, une question de perspective (link), La Recherche n°418, 01/04/2008.

domenica 28 luglio 2013

Visibly true

"Les lunes de Jupiter c'était son sujet préféré. Pinheiro dit que quand la nuit est noire et le ciel et dégagé, moins d'un homme sur mille peut les apercevoir à l'oeil nu. Autant dire personne. Avant l'invention de la lunette astronomique ceux qui y parvenaient n'osaient pas en parler." Hervé Le Tellier, Electrico W. , sixième jour - Manuela.

giovedì 16 maggio 2013


When the null-hypothesis is a meaningless SM without a Higgs boson, one may wonder how meaningful the results are. Ex falso quodlibet. Except good science, that is.

sabato 23 aprile 2011


Doesn't the persistent failure to detect cosmic gravitational waves in the LIGO experiment undermine the positivist prégnance->saillance reduction?

sabato 11 settembre 2010

Hawking's Nobel

Some people have argued that the inner radius of a black hole is not a physical, i.e. measurable, quantity. In fact I share that view, seeing no reason why the inner radius should coincide with the radius apparent to an observer on this side of the horizon. If those arguments are correct, they empty Hawking's theory of black hole radiation of any physical content, since its predictions would depend on a free parameter. On the other hand, should black hole radiation be detected, those arguments would be proven erroneous.

venerdì 23 luglio 2010

Fabulous accuracy

It is widely claimed that quantum field theory (as many-body perturbation theory is commonly referred to) provides, via renormalization, fantastically precise predictions of experimental results, both in phase transitions and in particle physics. However the relevant series are notoriously divergent, so that Borel transformations are used to extract satisfactory results.
For phase transitions the commonly cited works are those of Zinn-Justin and coworkers, which however rely on several additional adjustable parameters. In his survey [1] Zinn-Justin states with crystalline openness: "rho is a free parameter, adjusted empirically to improve the convergence of the transformed series ... Eventually the method has been refined, which involves also introducing two additional free parameters. ... It is clear from these remarks that the errors quoted in the final results are educated guesses based on large numbers of consistency checks.". While quotes out of context can be deceptive, personally I am left with some doubts about the predictive character of the theory.
[1] Jean Zinn-Justin, Phase Transitions and Renormalization Group from Theory to Numbers, Séminaire Poincaré 2, 2002, 55-74 (link).

giovedì 21 gennaio 2010

Ex nihilo

From Darwinist tautologies to decoherence theory's unphysical hidden assumptions, spontaneous morphogenesis appears as the founding myth of modern "scientific" ontology.

martedì 8 dicembre 2009


The possible inadequacy of temperature as commonly used in thermodynamics is suggested by Truesdell on the basis of theoretical considerations. The M'pemba effect provides stark experimental relevance to his remarks.

In one famously hacked email climate researcher Kevin Trenberth said "We're simply not tracking where the heat is going". The same could be said concerning the M'pemba effect. One may venture to guess that the two problems are not unrelated.

domenica 13 settembre 2009

Laws and models

Some readers may agree with the view that laws are man-made rules to regulate human behaviour ("Lex est quod populus iubet atque constituit" i.e. "the law is what the people order and establish" as Gaius put it). Others may regard laws as god-given. Actually the modern idea of physical law was introduced by a deeply religious thinker who regarded his work in theology as not less relevant as, and indeed intimately related to, his formidable contribution to natural philosophy. Nowadays laws are widely regarded as anthropic constructs. Yet there is a deep reluctance to view the physical laws of yore as anthropic rules that we use to build models that describe, organize, relate, extrapolate and, ideally, predict some of our perceptions. The religious background is still there, deeply embedded into the currently fashionable metaphysical objectivism, underlying the authority of the so-called scientific community (consider e.g. the respective impact of the statements: "the purported effect would violate the laws of physics" - "our customary models appear inadequate to describe the purported effect").

NB. The seed for the above "law vs. model" argument was provided by a remark that I heard a few years ago after a conference by Rovelli and others at the FestivalFilosofia in Modena. I remember that its author was an aeronautcal engineer and that at first I found his intervention deeply irritating. Yet it bore fruit.