http://books.google.com/books?id=JokgnS1JtmMC
"Relativity and Its Roots" By Banesh Hoffmann
p.92: "There are various remarks to be made about this second principle. For instance, if it is so obvious, how could it turn out to be part of a revolution - especially when the first principle is also a natural one? 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. If it was so obvious, though, why did he need to state it as a principle? Because, having taken from the idea of light waves in the ether the one aspect that he needed, he declared early in his paper, to quote his own words, that "the introduction of a 'luminiferous ether' will prove to be superfluous."

In fact, the Michelson-Morley experiment confirmed the prediction of Newton's emission theory of light: the speed of light is variable and obeys the equation:

c' = c + v (1)

where c is the speed of light relative to the light source and v is the speed of the light source relative to the observer. The experiment refuted the prediction of Maxwell's electromagnetic theory according to which the speed of light is variable and obeys the equation:

c' = c + v (2)

where c is the speed of light relative to the aether and v is the speed of the observer relative to the aether.

The former prediction is correct, the latter is wrong, but both are PHYSICALLY reasonable. Einstein's 1905 principle of constancy of the speed is a truncated form of equations (1) and (2):

c' = c (3)

and is PHYSICALLY absurd.

Guilty conscience forced Einstein to think of Newton's emission theory of light all along:

http://www.astrofind.net/documents/the-composition-and-essence-of-radiation.php
The Development of Our Views on the Composition and Essence of Radiation by Albert Einstein
Albert Einstein 1909: "A large body of facts shows undeniably that light has certain fundamental properties that are better explained by Newton's emission theory of light than by the oscillation theory. For this reason, I believe that the next phase in the development of theoretical physics will bring us a theory of light that can be considered a fusion of the oscillation and emission theories. The purpose of the following remarks is to justify this belief and to show that a profound change in our views on the composition and essence of light is imperative.....Then the electromagnetic fields that make up light no longer appear as a state of a hypothetical medium, but rather as independent entities that the light source gives off, just as in Newton's emission theory of light......Relativity theory has changed our views on light. Light is conceived not as a manifestation of the state of some hypothetical medium, but rather as an independent entity like matter. Moreover, this theory shares with the corpuscular theory of light the unusual property that light carries inertial mass from the emitting to the absorbing object."

At the end of his life (people often become exceptionally honest at the end of their lives) Einstein even confessed what he had done:

http://www.perimeterinstitute.ca/pdf/files/975547d7-2d00-433a-b7e3-4a09145525ca.pdf
Albert Einstein 1954: "I consider it entirely possible that physics CANNOT BE BASED UPON THE FIELD CONCEPT, that is on continuous structures. Then nothing will remain of my whole castle in the air, including the theory of gravitation, but also nothing of the rest of contemporary physics."

Pentcho Valev
pvalev@yahoo.com

http://www.aip.org/history/einstein/essay-einstein-relativity.htm
This reprints an essay written ca. 1983, "'What Song the Syrens Sang': How Did Einstein Discover Special Relativity?" in John Stachel, Einstein from "B" to "Z".
"This was itself a daring step, since these methods had been developed to help understand the behavior of ordinary matter while Einstein was applying them to the apparently quite different field of electromagnetic radiation. The "revolutionary" conclusion to which he came was that, in certain respects, electromagnetic radiation behaved more like a collection of particles than like a wave. He announced this result in a paper published in 1905, three months before his SRT paper. The idea that a light beam consisted of a stream of particles had been espoused by Newton and maintained its popularity into the middle of the 19th century. It was called the "emission theory" of light, a phrase I shall use.....Giving up the ether concept allowed Einstein to envisage the possibility that a beam of light was "an independent structure," as he put it a few years later, "which is radiated by the light source, just as in Newton's emission theory of light.".....An emission theory is perfectly compatible with the relativity principle. Thus, the M-M experiment presented no problem; nor is stellar abberration difficult to explain on this basis......This does not imply that Lorentz's equations are adequate to explain all the features of light, of course. Einstein already knew they did not always correctly do so-in particular in the processes of its emission, absorption and its behavior in black body radiation. Indeed, his new velocity addition law is also compatible with an emission theory of light, just because the speed of light compounded with any lesser velocity still yields the same value. If we model a beam of light as a stream of particles, the two principles can still be obeyed. A few years later (1909), Einstein first publicly expressed the view that an adequate future theory of light would have to be some sort of fusion of the wave and emission theories......The resulting theory did not force him to choose between wave and emission theories of light, but rather led him to look forward to a synthesis of the two."

John Stachel is right. Einstein did not have to choose between wave and emission theories - he simply killed both of them and then theoretical physics died. John Stachel finds this very funny:

http://www.perimeterinstitute.ca/index.php?option=com_content&task=view&id=317&Itemid=81&lecture_id=3576
John Stachel: "Einstein discussed the other side of the particle-field dualism - get rid of fields and just have particles."
Albert Einstein: "I consider it entirely possible that physics cannot be based upon the field concept, that is on continuous structures. Then nothing will remain of my whole castle in the air, including the theory of gravitation, but also nothing of the rest of contemporary physics."
John Stachel's comment: "If I go down, everything goes down, ha ha, hm, ha ha ha."

Pentcho Valev
pvalev@yahoo.com