Pentcho Valev wrote:const wrote:Положителното: Упражняваме си английския и френския. Merci, Mr. Valev!
Отрицателното: Г-н Вълев е като Бойко Борисов: накъдето и да се обърнеш, все той. Страх ме е, че ако някой реши да каже нещо друго, вече никой няма да го забележи.
Все пак само от няколко дни се въртите и аз се появявам от всички посоки. Но може би наистина прекалих - нека направим дълга почивка.
(Да си завърша все пак темата - после наистина можете да спрете да се въртите и да гледате само в една посока.)
Lakatos' PROTECTIVE BELT philosophy is a special case of the MAGICIAN'S HAT philosophy:
The MAGICIAN'S HAT philosophy: Science is taken to constitute the interior of a magician's hat where you put ties which are then turned to rabbits. The magician is free to secretly rearrange the interior of the hat so that always rabbits and never wolves jump out of it. The public declares itself ready to boycott the seances if wolves and not rabbits jump out of the hat but in fact loves the magician so much (there are hymns "Divine Magician" and "Yes we all believe in the hat, hat, hat") that seances would take place even if Tyrannosaurus rex jumped out of the hat.
Other contributions to the MAGICIAN'S HAT philosophy:
Karl Popper: "On the other hand, I also realized that we must not exclude immunizations, not even all which introduce ad hoc auxiliary hypothesis....All this shows not only that some degree of dogmatism is fruitful, even in science, but also that logically speaking falsifiability or testability cannot be regarded as a very sharp criterion."
Thomas Kuhn: "Something even more fundamental than standards and values is, however, also at stake. I have so far argued only that paradigms are constitutive of science. Now I wish to display a sense in which they are constitutive of nature as well."
Paul Feyerabend: "Today science prevails not because of its comparative merits but because the show has been rigged in its favour."
Pentcho Valev wrote:
http://bertie.ccsu.edu/~dsb/naturesci/P … katos.html
"Lakatos distinguished between two parts of a scientific theory: its "hard core" which contains its basic assumptions (or axioms, when set out formally and explicitly), and its "protective belt", a surrounding defensive set of "ad hoc" (produced for the occasion) hypotheses. (...) In Lakatos' model, we have to explicitly take into account the "ad hoc hypotheses" which serve as the protective belt. The protective belt serves to deflect "refuting" propositions from the core assumptions..."
http://www.physics.queensu.ca/~phys242/Section2_3.pdf
"Because the GTs [Galilean transformations] are clearly not consistent with Einstein's two postulates, we are going to have to develop a new set of transformations: the Lorentz transformations."
Historically the protective belt (Lorentz transformations) was created before the hard core (Divine Albert's 1905 postulates). Without the protective belt, Divine Albert's postulates (more precisely, his light postulate) would have been immediately refuted by the Michelson-Morley experiment:
http://philsci-archive.pitt.edu/archive … Norton.pdf
John Norton: "Einstein regarded the Michelson-Morley experiment as evidence for the principle of relativity, whereas later writers almost universally use it as support for the light postulate of special relativity......THE MICHELSON-MORLEY EXPERIMENT IS FULLY COMPATIBLE WITH AN EMISSION THEORY OF LIGHT THAT CONTRADICTS THE LIGHT POSTULATE."
http://books.google.com/books?id=JokgnS1JtmMC
"Relativity and Its Roots" By Banesh Hoffmann
p.92: "Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether."
James H. Smith "Introduction à la relativité" EDISCIENCE 1969 pp. 39-41: "Si la lumière était un flot de particules mécaniques obéissant aux lois de la mécanique, il n'y aurait aucune difficulté à comprendre les résultats de l'expérience de Michelson-Morley.... Supposons, par exemple, qu'une fusée se déplace avec une vitesse (1/2)c par rapport à un observateur et qu'un rayon de lumière parte de son nez. Si la vitesse de la lumière signifiait vitesse des "particules" de la lumière par rapport à leur source, alors ces "particules" de lumière se déplaceraient à la vitesse c/2+c=(3/2)c par rapport à l'observateur. Mais ce comportement ne ressemble pas du tout à celui d'une onde, car les ondes se propagent à une certaine vitesse par rapport au milieu dans lequel elles se développent et non pas à une certaine vitesse par rapport à leur source..... Il nous faut insister sur le fait suivant: QUAND EINSTEIN PROPOSA QUE LA VITESSE DE LA LUMIERE SOIT INDEPENDANTE DE CELLE DE LA SOURCE, IL N'EN EXISTAIT AUCUNE PREUVE EXPERIMENTALE. IL LE POSTULA PAR PURE NECESSITE LOGIQUE."
If the speed of the photon varies with the gravitational potential V in conformity with the equation c'=c(1+V/c^2), then, in a sense, the photon behaves like a cannonball and its speed will vary with the speed of the light source v in conformity with the equation c'=c+v.
In 1911 Divine Albert explicitly established the truth of the antecedent and he also knew that, by applying the equivalence principle, one would be able to easily prove the validity of the above conditional:
http://www.physlink.com/Education/AskExperts/ae13.cfm
"So, it is absolutely true that the speed of light is not constant in a gravitational field [which, by the equivalence principle, applies as well to accelerating (non-inertial) frames of reference]. If this were not so, there would be no bending of light by the gravitational field of stars....Indeed, this is exactly how Einstein did the calculation in: 'On the Influence of Gravitation on the Propagation of Light,' Annalen der Physik, 35, 1911. which predated the full formal development of general relativity by about four years. This paper is widely available in English. You can find a copy beginning on page 99 of the Dover book 'The Principle of Relativity.' You will find in section 3 of that paper, Einstein's derivation of the (variable) speed of light in a gravitational potential, eqn (3). The result is,
c' = c0 ( 1 + V / c^2 )
where V is the gravitational potential relative to the point where the speed of light c0 is measured."
So in 1911 Divine Albert badly needed a new protective belt that would deflect any attack against his 1905 false light postulate, an attack relying on the variability of the speed of light in a gravitational field. And he did build a new belt: GRAVITATIONAL TIME DILATION. This protective belt presupposes that rates of clocks vary with the gravitational potential while the speed of light remains constant.
Nowadays only silly Einsteinians insist that the speed of light is constant in a gravitational field. Einsteiniana's highest priests admit the variability but know that any hint at Einstein's 1911 protective belt makes this variability harmless:
http://math.ucr.edu/home/baez/physics/R … light.html
Steve Carlip: "Einstein went on to discover a more general theory of relativity which explained gravity in terms of curved spacetime, and he talked about the speed of light changing in this new theory. In the 1920 book "Relativity: the special and general theory" he wrote: ". . . according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity [. . .] cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity of propagation of light varies with position." Since Einstein talks of velocity (a vector quantity: speed with direction) rather than speed alone, it is not clear that he meant the speed will change, but the reference to special relativity suggests that he did mean so. (...) In general relativity, the appropriate generalisation is that the speed of light is constant in any freely falling reference frame (in a region small enough that tidal effects can be neglected). In this passage, Einstein is not talking about a freely falling frame, but rather about a frame at rest relative to a source of gravity. In such a frame, the speed of light can differ from c, basically because of THE EFFECT OF GRAVITY (spacetime curvature) ON CLOCKS and rulers."
Пенчо Вълев
pvalev@yahoo.com
