In addition, there were many critics (with or without physical training) whose ideas were far outside the scientific mainstream. These critics were mostly people who had developed their ideas long before the publication of Einstein's version of relativity, and they tried to resolve in a straightforward manner some or all of the enigmas of the world. Therefore, Wazeck (who studied some German examples) gave to these "free researchers" the name "world riddle solver" ("Welträtsellöser", such as Arvid Reuterdahl, Hermann Fricke or Johann Heinrich Ziegler). Their views had quite different roots in monism, Lebensreform, or occultism. Their views were typically characterized by the fact that they practically rejected the entire terminology and the (primarily mathematical) methods of modern science. Their works were published by private publishers, or in popular and non-specialist journals. It was significant for many "free researchers" (especially the monists) to explain all phenomena by intuitive and illustrative mechanical (or electrical) models, which also found its expression in their defense of the aether. For this reason they objected to the abstractness and inscrutability of the relativity theory, which was considered a pure calculation method that cannot reveal the true reasons underlying the phenomena. The "free researchers" often used Mechanical explanations of gravitation, in which gravity is caused by some sort of "aether pressure" or "mass pressure from a distance". Such models were regarded as an illustrative alternative to the abstract mathematical theories of gravitation of both Newton and Einstein. The enormous self-confidence of the "free researchers" is noteworthy, since they not only believed themselves to have solved the great riddles of the world, but many also seemed to expect that they would rapidly convince the scientific community.