Criticizing Lorentz's 1904 theory, Abraham (1904) held that the Lorentz contraction of electrons requires a non-electromagnetic force to ensure the electron's stability. This was unacceptable to him as a proponent of the electromagnetic worldview. He continued that as long as a consistent explanation is missing as to how those forces and potentials act together on the electron, Lorentz's system of hypotheses is incomplete and doesn't satisfy the relativity principle. Poincaré (1905) removed this objection by showing that the non-electromagnetic potential (" Poincaré stress ") holding the electron together can be formulated in a Lorentz covariant way, and showed that in principle it is possible to create a Lorentz covariant model for gravitation which he considered non-electromagnetic in nature as well. Thus the consistency of Lorentz's theory was proven, but the electromagnetic worldview had to be given up. Eventually, Albert Einstein published in September 1905 what is now called special relativity, which was based on a radical new application of the relativity principle in connection with the constancy of the speed of light. In special relativity, the space and time coordinates depend on the inertial observer's frame of reference, and the luminiferous aether plays no role in the physics. Although this theory was founded on a very different kinematical model, it was experimentally indistinguishable from the aether theory of Lorentz and Poincaré, since both theories satisfy the relativity principle of Poincaré and Einstein, and both employ the Lorentz transformations. After Minkowski's introduction in 1908 of the geometric spacetime model for Einstein's version of relativity, most physicists eventually decided in favor of the Einstein-Minkowski version of relativity with its radical new views of space and time, in which there was no useful role for the aether.