"With very few exceptions, philosophers do not know much science and do not understand it, which is quite natural because science lies beyond the boundaries of typical philosophical subjects such as ethics, aestetics, and gnosiology. But while in the free countries philosophers are quite harmless, in the dictatorial countries they constitute a great danger for the development of science. In Russia, state philosophers are bred in the Communist Academy in Moscow and are placed in all the educational and research institutions to prevent the professors and researchers from falling into idealistic, capitalistic heresies. The state philosophers are usually familiar with the subject of the research institution they are going to supervise, being either former schoolteachers or having taken in the academy a one-semester course on the subject in question. But they rank in the their power above the scientific directors of the institution and can veto any research project on publication which deviates from the correct ideology. One notable example of philosophical dictatorship in Russian science was the prohibition of Einstein's theory of relativity on the ground that it denied world ether, "the existence of which follows directly from the philosophy of dialectical materialism". It is interesting to note that the existence of the "world ether" was doubted long before Einstein by Engels, who in one of his letter to friend wrote "...the world ether, if it exists"."