"The two first articles (January and March) establish clearly a discontinuous structure of matter and light. The standard look of Einstein's SR is, on the contrary, essentially based on the continuous conception of the field." http://arxiv.org/ftp/physics/papers/0101/0101109.pdf

"Einstein's March paper treated light as particles, but special relativity sees light as a continuous field of waves." http://www.pbs.org/wgbh/nova/einstein/genius/

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." John Stachel, Einstein from 'B' to 'Z', p. 151 https://www.amazon.com/Einstein-B-Z-John-Stachel/dp/0817641432

Feynman unwittingly confirms that "physics cannot be based upon the field concept, that is on continuous structures":

Richard Feynman: "I want to emphasize that light comes in this form - particles. It is very important to know that light behaves like particles, especially for those of you who have gone to school, where you probably learned something about light behaving like waves. I'm telling you the way it does behave - like particles. You might say that it's just the photomultiplier that detects light as particles, but no, every instrument that has been designed to be sensitive enough to detect weak light has always ended up discovering the same thing: light is made of particles." https://www.amazon.com/QED-Strange-Theory-Light-Matter/dp/0691024170

Banesh Hoffmann, Einstein's collaborator, admits that, originally ("without recourse to contracting lengths, local time, or Lorentz transformations"), the Michelson-Morley experiment was compatible with the variable speed of light posited by Newton's discontinuous model of light and incompatible with the constant speed of light posited by the continuous (waves-in-ether) model of light and "borrowed" by Einstein in 1905:

"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." Banesh Hoffmann, Relativity and Its Roots, p.92 https://www.amazon.com/Relativity-Its-Roots-Banesh-Hoffmann/dp/0486406768

Albert Einstein: "I introduced the principle of the constancy of the velocity of light, which I borrowed from H. A. Lorentz's theory of the stationary luminiferous ether..." https://en.wikipedia.org/wiki/Lorentz_ether_theory

See more here: https://twitter.com/pentcho_valev

Pentcho Valev

John Norton: "Einstein could not see how to formulate a fully relativistic electrodynamics merely using his new device of field transformations. So he considered the possibility of modifying Maxwell's electrodynamics in order to bring it into accord with an emission theory of light, such as Newton had originally conceived. There was some inevitability in these attempts, as long as he held to classical (Galilean) kinematics. Imagine that some emitter sends out a light beam at c. According to this kinematics, an observer who moves past at v in the opposite direction, will see the emitter moving at v and the light emitted at c+v. This last fact is the defining characteristic of an emission theory of light: the velocity of the emitter is added vectorially to the velocity of light emitted. [...] If an emission theory can be formulated as a field theory, it would seem to be unable to determine the future course of processes from their state in the present. As long as Einstein expected a viable theory of light, electricity and magnetism to be a field theory, these sorts of objections would render an emission theory of light inadmissible." http://www.pitt.edu/~jdnorton/papers/companion.pdf

Again: "Imagine that some emitter sends out a light beam at c. According to this kinematics, an observer who moves past at v in the opposite direction, will see the emitter moving at v and the light emitted at c+v."

This is OBVIOUSLY true. The alternative is just nonsense. Einstein wrestled with his conscience "over a lengthy period of time, to the point of despair" before introducing the nonsense:

John Stachel: "But this seems to be nonsense. How can it happen that the speed of light relative to an observer cannot be increased or decreased if that observer moves towards or away from a light beam? Einstein states that he wrestled with this problem over a lengthy period of time, to the point of despair." http://www.aip.org/history/exhibits/einstein/essay-einstein-relativity.htm

More here: https://twitter.com/pentcho_valev

Pentcho Valev